Shared Projects

Breaks out the Raspberry Pi (A or B, Rev. 2) GPIO header to an ARM 20 JTAG header. It will also work with Raspberry Pi A+ and B+, so long as you take care of the 26 to 40 pin conversion. I imagine it will also work with the Raspberry Pi 2, but I’ve not tried it out.

This is for debug access to the ARM core of the Broadcom chip, not the Video IV core.

I use an Olimex ARM-USB-OCD-H JTAG but this should work well enough with any standard ARM 20 JTAG debugger. Note that the DBGRQ and DBGACK pins are unconnected.

There is no pin on the GPIO header to initiate a system reset. Raspberry Pi boards have an unpopulated header (called P6 on Rev. 2 A and B boards, called Run on later boards). Solder in a 2 pin length of breakaway, and connect to the reset header on the JTAG breakout. Connect pin 1 to pin1, pin 2 to pin2. Then the JTAG adapter will be able to initiate a system reset.

The pins are not configured for JTAG by default at system reset. The pins are GPIO pins that have to be configured to alternate functions by software at boot time. For an example,see the armjtag project by David Welch.

The layout of the UART serial port breakout is the same as the Beaglebone Black, This is convenient for connecting USB to TTL serial adapters, such as the FTDI Friend or the FTDI Basic. Like the Beaglebone Black, pins 2, 3 and 6 of the UART header are unconnected.

Apple II Joystick to USB Adapter. Details can be found at www.flitey.com

Soap Bubble Machine

Added PTHs for easy mounting on the bubble display frontpack.

5V 15-watt buck converter PCB

What to do when you have a partial reel of 74AHCT08 chips burning a hole in your pocket? Design a 20 Input AND gate of course.

Yes, this actually works. There are 10k pulldowns on all inputs so that they won’t pick up on noise. Apply logic high signals to all inputs to test it.

I made this board just for fun. Perhaps it would make for a good SMD soldering challenge… I gave one to a Digital Electronics professor who was retiring and he loved it.

BOM

• U1-U5: 74AHCT08 SOIC-14 (or similar logic family)
• U6: 74LVC2G17 SOT-23-6
• D1: B340A Schottky Diode SMA
• PWR LED: 0805 SMD (color of your choice)
• HIGH and LOW LEDs: 1206 SMD (colors of your choice)
• R1-R3: 330 ohm 0603
• Pulldown resistors (back side): 20x 10k ohm 0603
• C1-C6: 100 nF 0603
• C7: 10 uF 1206 SMD 10V (or substitute with ceramic cap)
• 2 Pin Headers: 1x2 0.1" standard header pins
• 40 pin Header: 2x20 0.1" standard header pins

Eagle Files

https://github.com/SyncChannel/20-Input-AND-Gate

devilCaster - Connector board for Telecaster Triple Deluxe. Factory HHH wiring with DP3T pickup switch. All the device connections are done on the board, and mounted inside the body cavity. Made this as a base for other circuit level modifications. More to come.

PLCC-44 breakout

PLCC-28 breakout

Second version of board to connect sensors to computers for programming and diagnosis

Particle Photon Board for Automated Watering

Particle Electron Carrier Board v2.2

LT3652 based MPPT solar charger for a single LiFePo4 cell

The LT3652 is a 2A multi chemistry MPPT charger controller from Linear Technology. You can charge other cells by simply changing the values for R1 - R4 (R1 and R2 actually are one resistor with 223k for LiFePo4) according to the datasheet.

github repository: https://github.com/dpaessler/LT3652-MPPT

usb power separator