After moving twice this summer, I finally got my workbench set up again (at least enough to start building stuff again). So I was able to build the latest version of the LCD ARM dev board (http://dorkbotpdx.org/blog/scott_d/arm_lcd_development_board). It works fine and I think all the errors from the previous version are fixed. So I've attached the Eagle files and the BOM. There is a spreadsheet version of the BOM which has pointers to purchase the various parts and a text BOM which has the part locators for the Eagle board layout as well as the values for the jellybean parts.
Recently I posted about the ARM based LCD development board I showed at a Monday DorkbotPDX meeting. At that time, I was waiting for another revision of the board before releasing the Eagle files. I got the next version back and it looks OK so I've attached the files.
The firmware source code is available on GitHub.
This is a ARM LPC1343 development board with a nice 132x162 16 bit color TFT LCD display, a microSD card, USB and LiPo recharging. I used it as a name badge at the San Mateo Maker Faire this year.
I've been getting interested in the Parallax Propeller chip lately and decided to dive in by designing a breakout board for the chip. I based my design on the reference designs given by Parallax so nothing really new there. I decided to include an EEPROM chip on the board so that programs could be stored between power cycles.
One of the main reasons I have been interested in gyroscopes and accelerometers is to measure tilt angle for things like balancing robots. So after building Paul's board with the three axis accelerometer and two axis gyro, I moved on to doing the software to use the board to measure tilt.
At the last Monday meeting I picked up a gyro/accelerometer kit from Paul. This is a successor to his accelerometer board which several of us have built successfully. This new board is a more complex build, both because it has two LGA packaged sensors and also because it is pretty tightly packed and almost all of the discrete components are
0603 0402 (I thought they looked small....) packages. I used a couple of single package solder paste stencils (LGA 12 and LGA 16) to put paste down for the two sensor chips and put paste on by hand for everything else.
While poking around Digikey for various sensor chips, I ran across the Freescale MMA7455. This seemed like a really nice 3 axis digital output accelerometer and it only costs $2.00 in single quantities. The specs seemed pretty nice for such an inexpensive chip: SPI or I2C output, 2g, 4g or 8g selectable range, tap, threshold and freefall detect with two interrupt outputs and/or continuous sample mode. So I ordered one and made a quick breakout board on one of the last group board orders. I didn't have a lot of time to get the design together so I made it pretty simple.
It was a good turnout for the open workshop at PNCA on Sunday. Don and Monty both got their hot plate systems up and running and soldered some boards. A couple of others started to put together their temperature controller boards and some questions came up about things I may not have made clear enough before:
The current versions of the Eagle files, .hex files and source code can be found at http://dorkbotpdx.org/blog/scott_d/temperature_controller_board_final_design
To install the temperature controller software on a new ATMega328 you can either load the .hex files or build from the Arduino source code. If you choose to load the .hex files, you should load both the temp_control.hex which is the program code which should be loaded into flash memory and also eeprom.hex, which contains some parameters for the controler which reside in eeprom memory.
I populated one of the temperature controller boards, did some testing and then loaded the PID software and tried out the IR sensor. So far, everything seems to be working. I don't have any of the thermocouple chips to try out so that will have to await the next parts order. But so far, so good. I'll be happy to help anyone get their board built out and running.