Monday, February 19, 2018

Lobot A-Star Micro

Lobot on the A-Star Micro and Arduino Micro

The Lobot can also be used as an ISP programmer for the A-Star Micro from Pololu and the Arduino Micro clone.

The A-Star Micro is used in the Atreus. I replaced the bootloader on the Atreus I built with the LUFA Mass Storage bootloader. It would have been a lot easier to flash the bootloader with the Lobot.

The A-Star Micro is similar to the Pro Micro, but much smaller. It comes with the same Caterina type bootloader.

The only change is that the pogo pins are installed in the 6 pin ISP header location. I took apart a pin header and built a support. I doubled up the plastic shrouds to make it taller and soldered the pins on the ends to hold it in place.

 The Arduino Micro clone has the same ISP header.

Side view of the double stacked headers used as a support for the A-Star Micro when being programmed.

The ISP header pinout is fairly standard. It can probably be used to program other small AVR boards as well.

More info on the Lobot here.

Tuesday, February 13, 2018


Red and White Gherkin

Red PCB top and bottom plates. White PCB and white nylon standoffs and screws.

Monday, February 12, 2018


32 Key Macropad

Two 4x4x4x4x4 PCBs assembled into a 4x8 macropad.

This is running the same firmware as the 4x4x4x4x4, using only the left 8 columns. I also have a JSON file for use with

A single board 16 key version is here.

 Gateron clear PCB mount switches. Grab bag SA profile keycaps

 Arduino Micro clone attached to the bottom of the PCB.

 M2 spacers and screws hold the PCBs to the aluminum plate.

Sanded down the aluminum plate with 220 grit sandpaper to smooth the sharp edges and the burs on the drilled holes.

The solder bridges creating the electrical connections between the two boards. More info on how the boards are connected here.

Thursday, February 8, 2018

End Game

Nyquist Game Pad

This is one half of a Nyquist split keyboard made as a game pad. Keebio sold off some sets of incorrect PCBs at a discount. There is a problem with the circuit to connect the two halves. It can be fixed with some rewiring, but I left it alone and just made a big macropad.

There is white soldermask on only one side of the plate/bottom PCBs. This often happens if there is no copper on one side of the board. The PCB fabricator will omit the solder mask, since there is nothing to be soldered on that side. Since this is a split design that can be flipped over it would look odd to have one side with soldermask and the other would be bare fiberglass.

Monday, February 5, 2018

PCB plate

PCB plate on a formed metal bottom

This is a Planck built from a OLKB Rev 2 PCB and a custom 1.6mm thick PCB plate on a formed metal tub style bottom. SA keycaps from a PMK grab bag. The bottom was from a group buy on /r/mechmarket.

The plate has 19mm spacing to be compatible with the Planck PCB. Most other keyboards use 19.05mm spacing (0.75inch). The switch cutouts have notches for switch top removal with compatible Cherry and Gateron switches.

The PCB is connected to a micro USB breakout board with 30 AWG wire. It is possible to place the keyboard rotated 180 degrees to have the LEDs on the top of the switches instead of the bottom. You would just reverse the order of the row and column pins in the firmware.

The spacers are 9mm M2. They fit perfectly. You can see the measurements I used to create the PCB plate.

Closeup of the connection to the USB header pins on the PCB. The Planck PCB is very easy to connect a different USB connector to.

The USB breakout board. There are many different styles. I got this one from eBay. It is held in place with 3M VHB heavy duty double sided tape.

View of the USB connector cutout.

Bottom of the tub style chassis. I wish OLKB still made their formed metal chassis. It was much sturdier (thicker sheet metal) than this and was compatible with the OLKB plates. It was also 10mm deep instead of 9mm. There was space to install some modifications under the PCB.

I used an OLKB formed metal bottom on the 40% Edward.

SA keycaps.