Tag Archives: PIC32

Parts received some not…

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As mentioned some of the items had later ship dates than others. As of June 16th I have received the IO board, the prototype boards, the LCD graphics w/LCD kit, and a power supply.

In addition to the development kit I have on order a few engineering samples for a few parts to test out before I pick vendors to program things based on and start purchasing real parts. These engineering samples will be mounted on “prototyping” boards that will either be custom built or ordered off the internet pre-made. Occasionally chips are used in a variety of ways so I will simply build a board to solder them down to and install pin headers to attach to on the board. These will also serve as “test” printed circuit boards as I learn to make boards on my own.

The ones I have received so far are a chip that has a real time clock/calendar in it and a chip that reads temperatures from a thermocouple probe. I still have requests out for a few ambient air temperature sensors and a few other things that will be used in additional projects that will eventually connect to/from the roaster computer.

The surprising part is that the clock chip is more or less around the size I expected (about guy little/pinky finger nail sized) BUT that the temperature chip is significantly smaller than I expected. It’s REALLY small. It’s so small that you could literally put at LEAST 16 of them on top of a single computer laptop keyboard key.

I am still waiting for the “brain” starter kit to arrive. This is where things get funky. When I ordered it the availability date for it and the ethernet card were listed as June 28th with an estimated delivery date of June 30th. This is good because I’ve got some free time from then until the middle of July so that arrival date was going to be good to let me work on things some. Today, though, I get this email. It now says that the ship date is changed to July 30th. My online invoice still shows the ship date as June 28th. The microchipdirect.com website says the availability date is July 2nd. So I’m thinking my chances of seeing this anytime soon are completely random and probably not likely.

Ordered parts this weekend for roaster controller.

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I’ve ordered some parts from Maxim/Dallas as well as from Microchip this past weekend. The stuff from Maxim is supposed to be coming US Postal Service so I don’t really know when they will arrive. I forgot to add a temperature sensor (ambient) to the order though so I will need to come back to that later. I need to compare it with a similar chip offered by Microchip to see which one I want to use. I believe the chips by Microchip are actually smaller and more accurate but I will need to confirm later.

According to Microchip’s website / my invoice the IO board, graphics board and LCD touch screen, Prototype cards, and a 9V Power Supply will ship sometime in the next couple days. They are scheduled for arrival on the 17th. The Network Card and PIC32 Starter Kit is not due to be available for 2 weeks and is supposed to arrive on the 30th.

Building a roast controller system.

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As alluded to earlier in the blog I am intending on building a roaster controller system.  I’m probably a bit of an over-achiever in terms of my projects because every time I create something on the internet for one of my websites, as part of a building project in the yard, or whatever else I’m creating I always over-analyze it.  In my career one of the areas I’ve been responsible for was “Disaster Recovery” planning for computer systems.  In other words my job was to over-analyze all the things that could go wrong and figure out a plan to deal with them.  At the same time I also have to plan all the ways for it to go right and have a plan so anyone can do it even without strong computer skills.

Focusing on a roast controller as mentioned I’ve already purchased some testing equipment for measuring temperature using a K type thermocouple. I am now finalizing the equipment that I’m going to use to build this and test it.  I’ve focused on using the PIC32 microprocessor due to its abilities to work easily with Ethernet, LCDs, and having many input/output circuits.  In addition it seems to be a robust platform for RTOS systems allowing a lot to be going on all at the same time.

To ease development I am choosing to embrace the development tools provided by the manufacturer.  This of course adds to the startup cost of the system but allows me to “try new things” in the future too using the development platform.  Once I finalize the project I would then order the individual components and manufacture my own circuit boards.  To start off I expect to need the following.

The Starting Parts

  1. DM320003-2 – PIC32 USB Starter Kit II – $55.00

    • Main processor (MCU) test board.
    • Contains PIC32MX795F512L processor.
    • 80 MHz with 512K Flash, 128K RAM. (this is actually a lot for a simple coffee roaster but is necessary for drawing graphical LCD, developing complex roasting profiles, and loading Ethernet overhead.)
    • Allows USB, Ethernet, LCD, I2C and SPI communications. 
  2. DM320002 – PIC32 I/O Expansion Board – $72.00

    • Connector to access pins and interface auxiliary boards.
  3. AC164132 – Fast 100Mbps Ethernet PICtail Plus Daughter Board –$49.99

    • Physical wired ethernet board for interface to DM320002.
  4. AC164126 – Prototype PICtail Plus Daughter Board – $20.00
    • Prototype boards to solder additional parts and extensions such as temperature probe chips, time devices, relays, etc.
  5. AC164127-3 – Graphics PICtail Plus Daughter Board with 3.2 Display Kit – $154.99

    • SSD1926 Graphics chip (kind of like a video card)
    • 3.2 QVGA (240X320) TFT LCD with 18-bit parallel RGB interface
    • Touch Screen

The Later Parts

The above parts allow me to start testing User Interface functionality without worrying too much about the circuit boards except for the occasional prototype board communicating with a sensor or two.  I’m doing that to determine the final touch screen configuration and “what is possible” on the screen real estate to determine if I want to pursue additional sensors and features.  It will also allow me to begin testing response time of various sensors on the prototype boards.  Some parts I expect to need:

  1. MAX6676 Thermocouple Amplifier
  2. DS3232 Real Time Clock
  3. Lots of resistors
  4. Lots of capcitors
  5. Various Transistors
  6. Lots of diodes
  7. Photosensitive PCBs
  8. PCB etch Chemicals and developer
  9. SMD soldering and hot air rework station
  10. Infrared circuit board pre-heater station
  11. Small Drill Press w/ bits for drilling PCBs
  12. Oscilloscope for dimmer testing
  13. Several relays and/or some dimmer circuits that need to be designed still.
  14. Probably a video camera at some point to demonstrate progress/results.