Getting to the bottom of things or clean until there is nothing left to clean

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So with a new (old) espresso machine comes a lot of responsibility cleaning.  Unfortunately one finds that just because someone says they cleaned a machine or that they say it has a problem with a pump does NOT mean that is true.  I’ve found that just because I take everything apart and soak it in cleaners and sanitizers and sometimes even hit it with a steam cleaner or some other method does not mean that someone else did.

After finding that something was shorting out I googled for things that cause this and the most likely scenario was that the heater was shorting out.  If you google “repair espresso heater element” or something similar you are likely to find one of two articles posted at Orphan Espresso about how to repair a heater element that has been damaged by water leaks.  In those articles they tell you to disconnect the power leads and get in between the metal of the boiler and the various parts of the heater element.  You will find a center metal element wrapped in various materials such as ceramic, other metal bits, and some sorts of resin/epoxy like material or other insulating things.  What happens is over the years the material cracks and breaks down and absorbs water like a sponge into all the nooks and other broken bits.

To repair this you have to test the metal boiler to element to prove there is a short with a resistance check using a multi-meter.  If a reading between the metal body and the heater element connection shows continuity then you have a short.  If you look around the wire and probe it with a fine metal pick you will probably see the material start to crumble and flake out.  You will need to dig out all of the material that will come free scraping and digging until it seems solid.  You will STILL have a short after this.  Depending on how adventurous you want to be you have two possible options.  If you have a heat gun you can start off there and possibly get lucky.

Previously I had been remodeling a house and used a heat gun to help speed up drying certain paint touch ups and for removing paint from woodwork.  I had picked up a heat gun from Home Depot to do this and had used this one linked from Amazon below:


Wagner Digital Heat Gun HT3500

You don’t really want to set it more than about 500 degrees and only want to hold it a few inches away waving it around somewhat quickly not lingering directly on it for more than a couple seconds. After a few minutes check it again with the meter. After about 10 minutes of warming it up repeatedly it should dry out and show no connectivity.  If it continues to show connectivity keep heating it up some more but if it never gets any better you might need to replace the heater.  The article on Orphan suggests removing the heater from the boiler and baking it,.  Depending on the age and “standardness” of your boiler you might not want to take it apart due to possibly having problems finding new gaskets.

In my case this is a non-standard machine.  If the gasket was damaged when taking it apart I’d have more difficulty finding a replacement.  I may still need to do this but for now the boiler wasn’t leaking around that area so I didn’t want to risk it.  Obviously you will need to try to drain the boiler and any water tanks before tipping your machine over to get to the heater parts if they are not available on the top or sides.

When I flipped the machine over I had a plate.

IMG_20160306_172742

After removing the bolts and taking off the plate I saw evidence of rust on the contacts.  Obviously water had come from somewhere at some point and got into the heater parts and clearly rusted the connectors.

IMG_20160306_172952

I went to an automotive parts store and purchased a clear liquid that removes rust.  You want something that eats the rust off and converts it.  Not something that converts the rust where it is and builds new layers.  Usually the kind that removes it and converts is somewhat clear or yellowish.  The one I used was “pH neutral” and thus not an acid.  You should probably try to find something like that.  The ones that are milky white or bluish are binders that convert the rust into a crusty black later bonded to the surface should not be used because it might cause issues with the electricity and the connector.

To rebuild the insulator around the heater I had to use a non-conductive high temperature epoxy.  I also used an insulator paint to cover the replaced epoxy.  When it was done it looked like this (I just painted over the end  more than was probably necessary but it’s not exactly easy to paint the insulator in sometimes).

IMG_20160309_224825

To seal it I used a tube of epoxy putty from Amazon:

Rectorseal EP-200

They have a larger tube that is the same material in case you use epoxy more regularly than I do. The 200 number on the end has to do with the size. an EP-400 is the bigger version of the EP-200 (2 ounce vs 4 ounce). This epoxy is NSF certified for food/drinking water contact and is safe for 500 degree Fahrenheit contact. You have to let the epoxy cure for at least an hour before painting it. I tested the multimeter readings after installing the epoxy. It shows a short until the epoxy is cured. The epoxy hardens in just under 15 minutes. I used some tools for working with moulding clay for making decorative beads and figures to push the epoxy down into the gap and smooth it off.

I picked up the tools from Michael’s (a craft supply chain) and paid way more (4-6 times) for it than the Amazon price:

11 piece Clay Tool Set

After it curing for an hour I then used an insulator varnish that I also picked up from Amazon:

MG Chemicals 4228 Red GLPT Insulating Varnish, 55 ml Bottle

The more commonly recommended insulator paint is something called Glyptal. Finding that might be possibly for you but I was not able to find it or anything like it nearby. I’m pretty sure the GLPT in the description is in reference to Glpytal. It is a strong insulator once dried and seals out moisture and is able to withstand a bit over 300 degrees Fahrenheit worth of heat. Glyptal has the same basic properties.

After letting it dry I found the same test results with the multimeter showing the short repaired. I used the heat gun to hurry up the drying so I could test the multimeter reading. I let the entire thing sit 24 hours before turning the heater on for testing.

Prior to working on the heater I tried cleaning the machine.  I had to remove the dispersion screen/bolt but the first screw driver I used was too small.  I found that the only screwdriver that worked well was a HUGE 5/8 inch wide flat screw driver.

IMG_20160306_154007

 

Once I did that with the correct screwdriver I found that the item did not seem like it had ever been cleaned because it never looked like it had been removed before my attempt.  It looked like this inside where the water comes in against the back side of the screen.

IMG_20160306_154229

 

Looking at the underside I saw evidence that the 8 outlets for the dispersion bolt were blocked.  Only 3 clearly had a strong water path etched in the gunk left in the machine due to it not being cleaned.

 

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After a good cleaning the dispersion screen/bolt looked like this:

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The area behind the dispersion screen looked like this:

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The following day I started up the machine and the heater did stay on and the whole system cycled through heating, steaming, and dispensing.  Pressure looked a little low until I ran some TSP through the system diluted in water.  After a few minutes of flushing the cleaner into the tank suddenly huge blobs of espresso grinds started squirting out of the machine and all of the water was dark dark brown.  Several gallons of water through the system later it came out clear-ish and I moved on to other cleaning solutions.  Following the brown water and espresso grind mixtures I found the pressure in the machine drastically improved.  I would say it was the difference of a trickle vs it gushing out once the brown had gone away.

As a result of the above I spent $362 for the machine on eBay.  I bought a $3.81 tube of epoxy putty and $10.33 for the insulator paint.  The rest of the items were pretty much optional and technically I only used about $0.10 worth of any of them.  So skipping the tools since I will likely still use them for other things or already had them – I spent $376.14 for this espresso machine.  Add to that about $15 worth of gas to drive to and from where I picked up the machine.

You bought what on eBay?

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So I’ve been searching eBay daily looking for an espresso machine worthy of bringing home.  After several years of searching I found a Salvatore Famosa.

SalvatoreFront

It had a E61 group, automatic controls, and you could supposedly steam and brew at the same time.  It was only about 90 minutes away and had to be local pickup.  It was reported to not get good pressure anymore and the owner thought it might be the pump.  The machine was a Salvatore Espresso Famosa.  With a few quick Google’s and checking out eBay’s prior sale history for machines with this name I found that they have recently sold for about $700 for the manual version and $1000+ for the automatic when they worked.

I decided to mark the machine as watched and waited for the bidding to end.  It was finishing on a Monday at 5:30pm local time.  I watched the bidding start at $99 and work its way up to the 200s.  On the last day I checked it a few times on my phone and it was getting up to $300.  It was above where I had hoped it would be but below what I was feeling was a fair price considering it was not completely working.  At 5:30 I sent in my max bid and watched it go up a couple times as final bidders tried to win it back and it ended at $362.

I quickly sent the owner a PayPal payment and asked in the note if I could pick it up on Saturday.  I soon got a response saying that was good and we agreed to meet at a Starbucks.  Prior to this I looked up most of the parts that were in the machine.  Most of the parts range from $8-16 for gaskets and and up to around $30 for some of the screens and water distributing parts.  The pumps were around $50.  Worst case the brain for it is around $200.  The heater was also around that much.  I was hoping I didn’t need most of those parts but I’d have to see how it went.

Saturday came and I drove down to pick it up.  After getting it hope I plugged it in.  The pump kicked on and it drew water into the boiler.  I pressed one of the buttons and water came out.  I waited a minute and……click followed by silence.  One of my GFCI sockets popped.  I reset and tried it again.  It immediately popped.  I thought to myself perhaps I had a bad GFCI socket?  Maybe something else was broken on it.  It had been raining pretty hard that night and the other socket that I knew wasn’t connected to stuff in the house was on my porch.  I knew it wasn’t attached to stuff I didn’t want to lose power to in case it shut down and I knew it had a good GFCI socket.  When we moved to the new house many of the GFCI sockets were defective and blew any time you so much as plugged a light bulb into it.   I knew that socket was great because I have a large 20 amp compressor that works on that socket when I’m working on things outside.  I wasn’t able to test it anywhere else that evening so I started taking the machine apart to try to see if I could perhaps disconnect some pieces to get it going further.

Since it was raining I wanted to wait until the rain stopped to plug it in elsewhere.  Shortly before leaving for work the next morning the rain stopped so I took it outside and….pop.  Clearly I had a short but I had no idea where.  I thought maybe it could be the pump or the brain or something else. During my break I came across Orphan Espresso’s tech article discussing how to bake a bad heating element and dig out the degraded insulators and pack it with epoxy putty, paint it with insulator paint, and return it to functioning.  I thought this probably was it.  When I got home I dug further into the machine.

 

IMG_20160306_153121

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Next up the bottom and the heater….

And the Espresso machine…

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So it has been quite a while since I wrote here last.  I have not given up on this project but I’ve been up to other things since then.  Around the time of my last post I moved to another city nearby and thus another house.  In my free time I remodeled a bunch of things in the previous house installing new wood laminate floors through most of the house, replaced the ugly stick on tile flooring in the bathrooms with sheet vinyl, sprayed the bedrooms with new paint, redid the landscaping, installed new fencing, replaced a bunch of plumbing for the kitchen sink, installed a new dishwasher, new moulding, replaced a skylight, new lighting, and put in a new hood over the stove.

It’s coming up on a year and a half now since that interruption and I think I’ve caught up on a lot of television and other things so I started getting back to coffee projects.

The first think I’ve been playing around with is a control knob that I intend to eventually use to control an espresso machine with.  I’ve got a basic prototype that lets me adjust a number for temperature with some buttons and lets me turn a knob to change a pressure.  It displays the information about it on an OLED display and then sends it over Bluetooth to my smartphone for the moment.  I’ll be coming up with a variation of this for the coffee roaster controller as well.

The other thing I’ve been doing is looking for an espresso machine.  Back a couple weeks ago I won an auction on eBay for a Salvatore Famosa espresso machine.  I’m not sure how old it is but the previous owner thinks it’s about 10 years old.

This machine has an E61 group head in it and is the automatic model where you power it on and it has buttons to start a single shot or a double shot vs the non-automatic where you flip a switch to run the pump to pull your shot and then you turn it off.  It has a connector for direct plumbing as well as an internal tank.  The boiler in it is a heat exchange boiler.  It has a hot water and a steam wand on opposite sides of the machine.

When I bought it the previous owner had said it was an As Is sale and the machine needed repairs or was sold as parts.  Since I’m not intimidated by a lot of electronics and mechanical stuff it sounded like it wasn’t too bad.  I picked it up over the weekend and have been working around inside it ever since.

In my next post I’m going to discuss what I actually found inside the espresso machine and update on status of finishing working on it.

 

VGDD SSD1963 EVK R3B w/ PIC32 I/O Expansion w/ USB II and TY700TFT800480

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As mentioned in my last post VGDD now supports a SSD1963 board.  Unfortunately I have the SSD1963 EVK R3B while VGDD was configured for using the Ultima R4.1 board both made by TechToys in Hong Kong.  I figured with enough time to work on it I’d figure it out.

Over the weekend I wired up the EVK board the same way that the Ultima is wired to the FX10A Hirose connector and use that to find the pins on the PIC32 I/O Expansion board.  The EVK board does not include any eeprom or flash chips on them to store touch screen calibrations so you need to supply your own.  As a result of not having that part programmed in yet I disabled the touch calibration until I can work out the correct adjustments to get it working with some form of memory.  My goal at this time was just to get the display working.

After a minor issue where the screen came up blue-tinted but otherwise generally working I kept playing around with the code in VGDD’s XML files and the resulting output trying to figure out what was going on.  A few times it got worse but for the most part it kept working with some type of issue.

Today after getting a few responses from VirtualFab on their brand new forum I started reading through the SSD1963 file to see what was different.  The owner of TechToys has also registered on the forum and he made a few comments about it as well. Armed with a little bit more information it turns out there is a different initialization command format when the Rev 02 TY700TFT800480 board is initialized vs the Rev 03 board that VirtualFab tested with the Ultima and built the XML files for.  After a minute or two I modified the USE_TY700TFT800480_R3 to not include the _R3 and confirmed that it still had the R2 (non _R3) code.  I then enabled an R2 XML file I created with the slightly different Horizontal and Vertical configurations and linked them to the graphics board, disabled the TouchInitialization, compiled, and my familiar roaster splash screen popped back up just fine.

The main difference between the R2 vs R3 LCD panel is that the R3 uses RGB signals while the R2 uses TTL and they are communicating at slightly different bit rates (at least that’s what I think is going on.)  So with that level of progress I decided it would be easier to order some SST25VF016 memory and wire it in to the project rather than to make it work with other memory since everyone seems to be using that same specific chip in their display boards.  It is possible to modify the files to support a Microchip 25LC256 (since I’ve done it in the past) but I figure it’s easier to just FLASH instead.

I’ve had a few conversations with John @ TechToys and he seemed receptive to some of my suggestions about adding some mounting holes to the EVK board so that it can be anchored more easily in a case if you wish to embed it rather than build your own. He also seemed to be considering at least providing a footprint to solder the flash memory to the board if you have it / need it. Since the board needs flash memory to store the touch screen calibration and it’s generally something you do once this will be helpful if it happens. No guarantees but at least it’ll probably be something he’ll think about with any future new board designs.

To wire up a SSD1963 EVK Rev3B to my PicTail Daughterboard I used the following configuration that mimics the Ultima wiring.

SSD PIC32 JP2 PIC32 SSD
TP_XR RB10 1 2 — —
TP_YU RB13 3 4 GND VSS
TP_XL RB12 5 6 VDD VDD
TP_YD RB11 7 8 — OE#
D17 9 10 RD4 WR#
D16 11 12 RD5 RD#
LE 13 14 RB15 CS#
D15 RD7 15 16 RD3 DC
D14 RD6 17 18 RD1 RESET#
 D13 RD13 19 20 RE0 D0
D12 RD12 21 22 RE1 D1
D11 RF0 23 24 RE2 D2
D10 RF1 25 26 RE3 D3
D9 RG1 27 28 RE4 D4
D8 RG0 29 30 RE5 D5
D20 31 32 RE6 D6
D21 33 34 RE7 D7
D22 35 36 RE9 TE
D23 37 38 5V 5V_EXT
D18 39 40 D19

The flash chips and a breakout should be arriving sometime in the next couple days.  The last tracking showed them being in San Francisco and should probably arrive tomorrow.

UPDATE – Flash arrived and I wired it to a generic eeprom/flash board I had made previously using a Radio Shack 276-159B and a SOIC-8 Breakout… wire as follows:

*Note* you may need to wire a 10k resistor to SST25VF016 pin 1/CE#.  Then wire 3.3v to the other side of it.  Mine worked without this done but it should probably be there.  Your mileage may vary.

SST PIC32 SST25VF016 PIC32 SST — —
CE# RD9 1 8 3.3V VDD .1uF Cap GND
SO RC4 2 7 3.3V HOLD#
WP# 3.3V 3 6 RD10 SCK
VSS GND 4 5 RD0 SI

 

SSD1963 now available in VGDD 5.1

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I’ve had a few conversations by email with the author of VGDD. He has quite good English knowledge and we’ve come up with a few background similarities that has made it pretty interesting to discuss the product here and there. A few times I’ve mentioned something I’ve done by modifying some of the files that came with the program or discussed something I’d like to see and it turns out he just did it in the next version he’s releasing in a day or two or intended people to be able to do what I had done in a future version that could fully support it easily.

Most of the time we’ve talked it’s been because I’ve looked at the PIC32 sitting on the table and I keep thinking of how I really need to get that touch screen going. I then sit down and update the program and end up building a bunch of screens and compiling things and discover a bunch of weird little bugs and he quickly fixes them and releases a new version.

A couple nights ago I roasted 4 batches of an Ethiopian coffee and found a couple more glitches in my Arduino roast profile and the cooling cycle but it’s getting better. It got me thinking about VGDD again, which I had upgraded to 5.0 a few weeks back, and it turns out there was a 5.1 version now. This time he’s now included TechToys Ultima R4.1 board that includes an SSD1963 controller on it. If you haven’t looked at it before this board accepts a Microchip PIC32 Starter Kit board and has a variety of other things built on such as the SSD1963, an MP3 Decoder, a footprint for a wireless network card and a few other connections. Combined with a 7 inch touch panel it’s about $139 + tax right now.  It seems to be an excellent product but I just think that it was a move in the wrong direction to squish so much into one board. Instead I would have rather it been made to be modular to let you enable/disable sections of it to use those pins in your own ways. I’ve been using the SSD1963 EVK 3B board hooked to my PIC32 expansion IO board for the initial testing I’ve done.  It ends up around $99 w/ a 7 inch touch screen.

My early little touch screen using Microchip brand boards was a lot more money and to get a 7 inch screen today with the new Epson controller would be about twice what I spent for the SSD1963.  The original little screen was pretty good to see what the roast was doing when I first started trying to build a coffee roaster but it was just too small.  This is why I started trying to build a 7 inch touch version of my roast controller which allowed a whole lot more to be done on the screen.

While I had gotten the SSD1963 working in some of the older VGDD versions by hacking the XML files I was not having the same luck with 5.0.  With version 5.0 of VGDD I kept getting errors when I compiled and had issues with the screen not working as I expected when I finally got it to compile and I didn’t have a lot of time to work on it.  Seeing SSD1963 in the Ultima board being supported in 5.1 I figure I just need to ensure I configure the wiring from the EVK board I have to mimic that of the Ultima board I should be able to get it to compile.

Lately (on the Arduino side) due to some changes with the serial output of the project and my attempts at adding more functions to the processing GUI I’ve found that I’ve managed to break the PID/LOG communication to the processing GUI and forgot to commit a copy to my home code repository server and there’s too many changes to really figure out which area got messed up without a lot of work. As a result that lack of visualization is really starting to become an issue so I’m really going to start trying to develop the PIC32 side more to at least process the output of the Arduino and run the touch screen to display it all.

I’m oncall for work this weekend but I hope to be able to verify the wiring with the Ultima schematic and make sure I cable up the EVK board properly and get a screen or two going again using VGDD. I’ll post the wiring info once I get it going.

Video of Test Run of RoastGeek Roaster Controller

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After some work mounting circuit boards and creating wiring harnesses to connect everything together I wired up a 5 volt power supply to run a case exhaust fan and fired up the coffee roaster controller for a quick test. The program was not optimized for a new bag of beans I was roasting so it didn’t hit good temperatures at the right times in my opinion but it worked.

At this time I have disconnected all of the FreshRoast SR500 control electronics and replaced everything from the wall to the heater and fan connections with my own boards. I’m using an Arduino Mega 2560 with an Ethernet Board (it gets NTP time to set time and date on the logs by itself and I hope to add some ethernet based communication to collect the log data without popping the microSD memory out). The Arduino is mounted in a Crib for Arduino and connected via wiring harness to a DB25 cable that connects to the back of a Ponoko laser cut case prototype.

I screwed up a few calculations on the Ponoko case but the idea will work and the glues I need to use will allow me to connect all the sides together and mount everything securely when I send it in for “round 2”. Inside the case I’ve got several Sparkfun boards as well as some other manufacturer breakout boards mounted to a “connector board” that links them all together and to the DB25. There is also a 25VAC transformer and my original RadioShack parts power control board. I need to figure out what I need to do to have a suitable AC handling PCB though since most of the easily produced boards would not have thick enough copper to handle the 1500 Watts of AC power to my understanding.

I still need to do a bit more work to get anywhere I’m comfortable with it. I’m intending to get most of the following done before I consider it “more than a rough prototype”:

  • Enable toggle for manual vs automatic controls
  • Replace PID code with a better system that I think I understand better to tune it properly
  • Create menu to setup automatic profiles
  • Allow ability to convert a previous manual run to an automatic profile
  • Fix wiring on a few sensors that didn’t register properly
  • Create a second board to replace the current board that includes many of the sensors directly on board
  • Move the 7 volt to 5 volt power supply inside the case to run the fan and start powering other sensors
  • Update the button matrix and change the way I drive the LEDs on it to minimize pin use.

Ultimately, however, it worked well enough. Once I get it through these items and kick out a new case I’ll start trying to find ways to document more of how this went together to help others figure out how to come up with something similar. After that I’ll begin working more on the PIC32 side trying to convert from Arduino to PIC32 and get my 7 inch touch screen mounted to a front panel and add more functions.

Pretty on the outside and ugly on the inside prototype

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So I’ve been busy doing a bunch of computer maintenance and looking into other things I’ve neglected while building the roaster so it’s been a bit slow.  I decided I wanted to start gluing corners together and drilling some holes to see how the case goes together so I can eventually get back to fixing the issues with the roast controller case.  Over the past several weeks I soldered together all of the boards, made wiring harnesses and figured out a bunch of “oops” moves I had made designing things when I got rushed for time.

Turns out I was not able to get stand offs locally in the sizes I had wanted so the heights are all screwed up where I placed holes on the outside surfaces.  I also forgot to specifically allocate power for the exhaust fan in the original design BUT I did have “Spare” pins allocated. The fan I ordered also was not the right size for the hole template I had used (Inside fan dimension vs outside screw / case dimension)… neither of them were actually labeled right the way every other fan I have is sized.

So with everything screwed or harnessed in place this is what I have for the Arduino…

The Arduino wired for Coffee Roaster control

It is a MEGA2560 mounted on a Crib for Arduino.  On top is an Ethernet Shield w/ microSD slot.  Then I used a variety of crimped headers to connect to some of the pins on the MEGA and on the ethernet shield.  I have twenty five lines in the bundle going to the Arduino.  I had some spare 10 strand cables from a project at Halloween and no 25 strand cables to use so I used one of those cable wraps to keep the all together after connecting DB25 to one end and header pins to the other.  Once the lid for the crib for Arduino is in place it then connects to the back of the enclosure.

Wiring Harness connecting to the back of the controller enclosure

As you may notice the sockets I was using for connecting the power out are the type that snap in.  The majority of these will not snap into most laser cut plastic sheets and instead are designed for aluminum cases.  The plug to the right on the other hand screws in.  These work great with a variety of thicker locations.  The fan was originally going to be on the inside with a wire cover on the outside but with the wrong size fan hole in use I had the wrong cover to fit the fans that I had that would fit the hole.

For the DB25 connectors it turned out good that I had decided to use a cut out pattern  that had the holes on the side for the anchoring hex nuts rather than just having them cut out so that I could mount them to the socket and anchor the connector.  Since the stand offs were too short they don’t allow me to anchor the PCBs to the bottom plate.  Instead I had to screw them to the back plate using normal screws and with the burnt circles on the laser cut work I had to use some washers too to keep it sturdy.  This is what the back plate looks like.

Rear Panel of controller

This panel includes – One non-filtered switched 15Amp Power Entry module, 2 snap in 15 amp convenience plugs, 1 5VDC fan, 2 DB-25.  The left one is the main guts for the LCD, TRIAC control, potentiometers, thermocouple, and a variety of other sensors.  The right includes all the non-essential stuff for backlighting all the buttons on the button pad and a few other things including spare wiring.  You cna see just a screw on the right since it was relatively intact and so it won’t block the DB25 plug being used.  The right DB25 has washers and screws in place.  These are primarily used to attached the PCB in place attached to the back side.

Next up is the inside view of the electronics area:

Rear View of the Back Panel

Rear view of the back panel.  I need to shrink up the crimp connectors around the wire  (they shrink like heat shrink tubing but is actually much firmer).  Also the connector on the right side (the switched power entry module) should have the screws more securely fastened with nuts and washers but this is mainly just a test to ensure it all fits together and then allow me to focus on some programming for a while to see if I can get more working and develop menus etc.  The clear acrylic bar is used to anchor the corners better.  I need to change the locations of the screws since I could not find screws the size I wanted without spending way too much for large quantities of them on the internet and having them shipped to me etc.  The thermocouple board on the right had the same issue with the stand offs so it is just floating loose in there right now.  I need to find somewhere to get the Omron thermocouple sockets where I dont need to order them by the 1000s since it looks like Ryan McLaughlin has stopped selling things on his site when they (used to) have problems getting the newer MAXIM thermocouple chip.  They’re all over the place now but he hasn’t restarted his store up so I don’t know the deal there.

Here is the view down into the enclosure from above:

Top view into enclosure

With the cover on:

Front panel installed on enclosure

Front panel running

Front Panel Running

When I send it back out again for a new case I hope to have a different board to install that will be switching the smaller breakout boards being designed onto the circuit board as well as add a power supply and possibly having an arduino board mated on top of the circuit board perhaps to bring more of the electronics inside.  I might want to try to get a Digilent board perhaps to try converting to it as a transition between Arduino and PIC32 before I completely switch to a dedicated PIC32.

I’ve also been looking at possibly creating a dedicated PC application to communicate with it directly via USB and over ethernet.  I am toying around with the “QT/QML” language but havent gotten too far with it.  I may just go back to Processing though.

RoastGeek Button Pad v 1.0

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This weekend the final resistor I was waiting for arrived.  As a result I was able to solder the button pad board together and mount all the buttons.  I placed the board on my infrared preheater, applied some solder paste using the syringe dispenser on each of the pads, and then using a pair of Weitus tweezers started placing 0603 resistors from the piece cut from a reel.  I then turned the heater on and let it sit for a bit before turning it up a few more times until I got close to the temperatures I needed.

RoastGeek Button Pad v1.0 on Infrared Pre-Heater with SMD resistors placed.

Without a stencil it’s pretty hard not to goop too much solder paste onto the pads.  In most cases I had a suitable amount but a few it got a bit too much.  For most of the cases I had too much I removed some while it was still liquid-like from the preheater softening the paste.  I used the tweezers with a tiny bit of paper towel to wipe some away on the worst spots.  Solder paste is essentially  a mixture of a type of flux with a fine dust of the solder.  When the temperature gets high enough the flux material starts to liquify and the solder particles flow with the wet flux-like material towards the meeting point of the pads and the item being soldered.  As you apply a final amount of heat the solder particles melt and the flux-like material starts to evaporate/burn up.  To do this I used a hot air rework station to heat up the area near the resistors.  It has a pretty gentle flow that I can adjust with a knob so I didn’t have any issue of the resistors blowing away.  This tends to be a common problem using a hot air rework tool to solder SMD parts.  Once they were all in place I turned down and then a bit later fully off the heaters and allowed it too cool down.

0603 Surface Mount Resistor soldered to the board with an infrared preheater and a hot air rework tool.

Once the surface mount resistors were in place I tested each pad on each side of every resistor and confirmed that the correct resistance was measured.  This was to confirm that I didn’t have any “over gooping” resulting in the resistor being jumped by solder underneath of it.  Everything checked out ok so I continued on to mounting the buttons and header pin connections by hand with a standard iron.

RoastGeek Button Pad v1.0 with buttons, caps, and headers mounted

At this stage I tested the board with an Arduino sketch and was able to measure each button as expected.  This board has a much more accurate number compared to the last board.  Each button previously would measure a number that ranged 3-4 from the highest to lowest reading.  This one is dead on for almost every single button except for 2 of them that vary by 1.

I then mounted the board to the back side of the control panel.  I discovered that the standoffs I am using are about 1-1.5mm too tall so I will need to either grind them down or find a different set of stand offs.  I’m thinking of getting some Nylon or ABS ones that have a self-retaining clip for the circuit board side and a threaded end for accepting a screw from the front panel.  I also need to begin wiring up some wiring harnesses to go between the LEDs and potentiometer over to the new board.

I’ll add a picture of the mounted board  here once that takes place.

PIC32 w/ TechToys SSD1963 EVK R3B + 7 inch display and VirtualFab VGDD

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First let me start off by saying…AAAAAIIIIGGGGGGHHHH!  Ok.  I never claimed to be an expert at what I was doing and I’ll have to say this one really made me fight for it.  I have been attempting to get my PIC32MX795F512L USB Starter Kit II attached to a IO Expansion board and then connect that to the TechToys SSD1963 EVK Rev3B board which then connects to the TY700TFT800480 7 inch touch screen.  Then to create my GUI I was using the VGDD software by VirtualFab.it.

I’ve had almost a week now of evenings and several days where I was uninterrupted and able to work on it.  It took a couple of evenings to make sure all the wiring was correct and get all the various parts assembled together for an EEprom to store calibration data to work.  Turns out I needed a bypass capacitor AND NOT to have a pull up resistor on the chip select pin even though it seemed to be used in most examples I found the opposite way.  Once I got past that issue I worked on getting the demo to work which required some tweaking since I was running the demo on a custom configuration that wasn’t a TechToys multimedia board with everything on it.

After finally getting the basic demo working ok I began trying to figure out VGDD’s XML files to add extra Display and Graphics Cards to the software.  I added an entry for each device and then started to customize the individual XML for each part.  After exporting the project and trying to compile it there was of course a LOT of errors.  In a few cases some of the lines got duplicated and in other cases I had to add additional lines or modify the driver slightly to work cleanly in VGDD’s wizard.

I still need to work on a problem where the exported VGDD project has something incorrectly set with the EEprom where the SPI isnt writing so it only shows a single screen and can’t navigate until the touch is calibrated.  Additionally since the SSD1963 is not part of the original MAL (Microchip Application Library) then I likely need to find an alternate place to put some of the files and explicitly map it that way in the VGDD templates.

Due to some previous problems with VGDD (I started using it very close to the beginning of its existence and it has had dozens of releases over several years now) where it seems my files got “scrambled” here and there I would get all sorts of weird issues while trying to compile them.  As a result I’ve started the screens over from printouts and need to figure out how to adjust a few buttons and text as well as add a whole lot more items to many of the menus.

Here’s the awful camera phone photos in a dimly lit room.  Once I get it working better and update the screens more I’ll dig out the better camera. I’m just happy that things are working right now.

PIC32 and SSD1963 board driving a 7 inch touch screen as programmed by VGDD

Test VGDD screen hacked to work on a SSD1963 board with minimal changes.

I’m pretty close to getting the XML worked out so that I don’t need to modify the VGDD code that gets generated but I suspect I’ll need to work on it for a few more evenings before I get it right.

Update 7/24/12 Afternoon – I’ve managed to get the EEprom code to read/write the calibration properly now from the beginning.  I’m seeing an off effect where the OutTextXY functions are not working while all of the static text displays fine and the functions that make it switch screens do not appear to function.  I have one section that defines the touch screen X/Y ADC pins that appears to be a duplicate with something in another section of code that I have to comment out and I have to force it to display a screen since it doesnt seem to happen automatically (may be part of the switching screen problem though).  I’m going to switch to a regular SSD1926 screen and generate code and start comparing because I must have disabled something making the screen objects invalid.  Outside of adding the display a screen command, and commenting out the other code section it does export without a bunch of errors so I am getting further along now.

Update 7/24/12 Evening- I’ve now managed to get straight through compiles to work without having to modify anything.  I had found an issue with the order of the screens where it tried to put one of the “master screens” as the first screen it loads.  For whatever reason this causes it to black out the screen and not show anything.  After switching it to a more appropriate screen it comes up ok.  It also now transitions from one screen to another when I press the buttons as well.  The only issue I’m having is when there is around 30 buttons on the screen it freaks out and stops displaying them.  I’ve been unable to find a notice about there being a 30 button limit but so far I’ve not found a way around it.  The code is all there for all of the buttons but they don’t show up.

PIC32MX795 on a IO Expansion Board connected to a SSD1963 EVK R3B and TY700TFT800480 7 inch touch screen from Tech Toys with GUI created by VirtualFab.it VGDD.

Preliminary PIC32 roaster GUI created in VGDD on a 7 inch touch screen using a SSD1963 controller.

First order of circuit boards from OSHPark.com

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If you were following comments in one of the previous blog posts I just received my first order of circuit boards from OSHPark.com. This order included version 1 of my button board and a preliminary interface board to connect a variety of sensors and some of my other boards to an Arduino Mega 2560.

I got to experience the “joy” of being one of the initial test subjects for the brand spanking new OSHPark.com site. It actually worked pretty well and was rather impressive in terms of the graphical response you got from it. It would evaluate the files you uploaded and convert them into a graphical rendering of the finished product. When I ran my boards through the system I did notice that the silkscreen appeared to be NOT the rear/bottom view as the site described but instead it was the “Superman X Ray Vision” view. If you’ve used Eagle and a few other competing PCB CAD programs this is what you normally see when working on your board. Your test will be “reversed” or “mirrored” and the holes will be in the positions they would be in from above. It is thus like you are looking through the layers from above. I mentioned this oddity in my comments on the job but don’t know if they’ve resolved it yet by changing the code or changing the description.

The timeline for my order is as follows:

  • May 21st – Placed Order (T=0)
  • May 25th – Tweet @laen replied by @OSHPark reported that the system is not sending notices yet. Indicates board have been reviewed and panelized. (T+4)
  • May 29th – Received official email that said boards on panel for May 31st.  Notice website reports May 30th as panel date. (T+8)
  • June 7th – Received notice saying boards sent to the fabricator. Probably just an update to the software of the site and the boards were sent prior to this point. (T+17)
  • June 8th – Received notice saying boards received from the fabricator awaiting de-panelization. (T+18)
  • June 15th – Boards apparently processed for postage based on postmark. (T+25)
  • June 18th – Received boards. (T+28)

As mentioned I expect most of the dates to be unreliable other than the fact that it took 28 days start to finish.  The site still has not changed from a status saying my boards are waiting to be de-panelized and nothing about being shipped.  Obviously it is a work in progress.

Here is the collection of boards received

First order from OSHPark.com. My Button Pad board and the preliminary interface board to connect a variety of sensors to the external Arduino mega.

The spacing seems to be exactly what the CAD said it would be and the holes drilled seem to be very accurate and centered like they should be including some of the very small vias.  I will need to crack off and dremel/sand off the rough spots from the edges where the boards were connected together.

More pics:

Interface board

Button Pad 1.0 with several buttons placed

Button Pad v1.0

Button Pad 1.0 Top

Button Pad 1.0 Rear

At this time I am waiting for 330 ohm 0603 resistors to arrive.  They were on back order and should arrive in a few more weeks.  Once they arrive I need to use my infrared preheater to heat up the boards and then do a quick solder on each of the resistors before connecting all the various through hole parts.  Once that happens I’ll update with a new photo showing the finished boards.