This is a boost converter powered LED board. It’s intended to be populated with 21 SM0603UV-405 UV LEDs, but really any 0603 LED would work just fine. The boost converter is the AP3015. The two 1210 caps are 10 µF, the inductor is 10 µH and the diode is an MBRA340 Schottky diode. The resistor divider values of 51.1kΩ and 3kΩ yield an output voltage of 22.14 volts, or 3.16 volts across each LED (there are 3 parallel strings of 7 LEDs in series). It’s recommended that the input power be 9 VDC.

Plugs into one of the headers on an Arduino Uno or other board to provide 4Mbytes of non-volatile storage.

For more information see: http://www.technoblogy.com/show?2JMU.

Cable for Tandy Portable Disk Drive similar to Rick Shears', with the electronics in the db25 shell.

BOM: https://www.digikey.com/short/pmb339

Assembly note: The cable clamp in this backshell does not effectively immobilize this cable, no matter how tight you clamp it. It’s just not designed for such a small diameter cable, and even adding a lot of heat shrink doesn’t work, because the result is still too round, while the cable clamp appears to be designed to work on an even fatter cable that has a bundle of all 25 wires, which will deform to an oval and fill the clamp properly. This thin cable with a lot of heat shrink still will not fill the clamp’s oval shape. Yet, we need THIS particular backshell and not most others, because most others will not fit into the opening on the back of a TRS-80 Model 100. So, you need to add some hot-glue inside the cable clamp during assembly to hold the cable from wiggling it’s way loose. The idea is for the hot glue to fill the gaps to either side of the cable, to act more like a grommet than a glue, holding the cable in place more by the fact of filling up the space in the clamp so the cable can’t wiggle side to side. It’s ok that hot glue isn’t reliable as a glue, in terms of sticking to the surface of the cable sheath long term. You don’t need to use a more serious glue if you were aware of how crappy hot glue is.

The differences between this and Rick’s original version are that it’s physically smaller, which allows more room for cable strain relief inside the backshell, and the solder pads for the db25 connector are longer and thinner, to allow for the use of a connector with through-hole pins instead of solder cups, because the pcb is too thick to fit between the solder cups.

There are still a few disadvantages to this arrangement. It’s more work than necessary to build.

The BKW4 version removes some steps and is a bit simpler to build. (No dupont pins, no dupont pin crimper, no backshell, factory molded db25 plug & cable)

Tandy Portable Disk Drive cable vBKW4

BOM: https://www.digikey.com/short/pbc3pp
http://tandy.wiki/TPDD

ARINC 429 transmitter using Digilent PMOD pin out. Designed for easy interfacing to many FPGA development systems. Uses Holt HI-8596PCI and OSTVN screw terminals.

This is a copy of the original by Alienwhoop https://oshpark.com/profiles/AlienWhoop

vertical board

horizontal board

MMA Array Adapter

MBC3 Flashcart based on retroreboot’s cartridge that uses 0603 components and has added support for 4MB roms

Order at 0.8mm not 1.6!!!

BOM

Changelog:

1.2: - Fixed missing traces

1.3: - Fixed some issues with the traces around Y1 - Rerouted the PCB

Breakout board for STP16CPC26 LED driver. Daisy-chainable, each board drives 16 independent strings of LEDs. Separate positive power line for LED strings allows up to 10 red or 5 green/blue/white LEDs per string. 4 wire interface ((Clock/Data/Latch/Brightness) from 3.3 or 5V Arduino & ilk. Global brightness adjustment via PWM, plus independent adjustment of each string with interrupt-driven driver.

An adapter board to attach a CP2104 board to ESP8266 and provide auto programming mode.

The “S” in SAO now stands for Serial.

This SAO will connect two badges together in a null modem arrangement, wiring one badge’s TX to the other’s RX and vice versa.

Put two shrouded 2x3 connectors on the bottom of the board. Put a 1x2 connector on the top and short it (or not) with a shorting jumper depending on whether you want to share power between the two badges or not.