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Parts
The parts to create the keyboard are described below. A few extra of the smaller parts is a good idea as sometimes things go wrong or get lost, especially diodes and LEDs.
In many cases just the footprint and specification matters, e.g. SOT-23 and BAV70, not the exact part or source. I've listed the specification and footprint but also specific parts and sources that I used or that seem like good choices. The sources are mostly focused on the USA, where I am.
On the Hillside 52 or 46, having the factory do PCBA saves sourcing many of these parts. This includes the SMT diodes, resistors, capacitors and ESD chip. Also optionally the reset on both and the battery power switches on the 52.
At their core, the boards need MCUs, diodes, TRRS jacks and optionally reset switches.
The 'By Hand' and 'PCBA' columns list how many of each part you need to source and solder yourself. For PCBA, the remaining parts will be sourced and soldered by the factory.
| Part | Type | By Hand | PCBA | Cost | Shops |
|---|---|---|---|---|---|
| MCU | ProMicro, Elite-C, Nice!nano | 2 | 2 | $36 | Keebio, LittleKeyboards |
| Diodes | BAV70 SOT-23 | 24, 28 or 30 | 0 | $5 | Digi-Key, Mouser, LCSC |
| TRRS Jack | MJ-4PP-9 or PJ-320A | 2 | 2 | $1 | Keebio, Amazon, LCSC |
| Reset Switch | 5.2 x 5.2 mm | 2 | 2 or 0 | $1 | Alps SKQG at Mouser, COMAX at Digi-Key, SparkFun, LCSC |
Either the Alps SKQG or a COMAX work as the reset switch.
The Hillside 46 ESD protection uses these additional parts:
| Part | Type | By Hand | PCBA | Cost | Shops |
|---|---|---|---|---|---|
| ESD chip | SRV05-4 | 2 | 0 | $2 | Digi-Key, Mouser, LCSC |
| Decoupling capacitor | SMT 0805 4.7uF 6.3v | 4 | 0 | $1 | Mouser, Digi-Key, LCSC |
With parts availability currently uncertain, here are DigiKey and Mouser searches for the diodes. Each diode is: BAV70, packaged as SOT-23-3, supplied as cut tape.
The switch details are:
- Alps SKQG SKQGAFE010 available from Mouser with 100 grams force.
- COMAX RS-187R05A2-DS MT RT available from Digi-Key
JLCPCB's available basic tactile switch, TS-1187A-B-A-B #C318884, has a leg profile that extends just 0.1mm (+- 0.25mm) further than the Alps and COMAX ones, though the pads of their suggested footprint are much larger and the body is 0.1mm smaller.
SparkFun also carries this switch, though I'm not sure whose version they have.
You can also go without the reset switch as you can set a key on a layer to do that. Or with tweezers you can briefly connect the two vias on the reset footprint, or their connected pads.
It is highly recommended that you socket the MCU as insurance against a damaged MCU bricking half of the keyboard. Or of a year from now wanting the latest cool MCU instead of the one soldered to your keyboard with the 24 closely spaced pins it came with. So I'm only going to go over the socketed approach. (The non-socketed approach does not need any extra parts anyway beyond the square pins that came with your MCU, pin that don't work with either of the below options.)
If you go with the ultra low profile headers, you need an MCU with a mid-mount USB socket. Otherwise the sockets will not close completely. And you should also leave the decoupling capacitor nestled under the MCU out of the PCBA order, or desolder it. That capacitor is a bit of over-kill and certainly unneeded if you don't use a battery.
- If you ever think you might want to use a wireless nice!nano, you want to use higher profile sockets to provide battery space under the facedown MCU. Of the higher profile sockets, Mil-Max has a higher profile socket that has just enough clearance for the MCU and battery. You can get similar machine pin sockets from several sources.
| Part | Type | Count | Cost | US Shops |
|---|---|---|---|---|
| Machine pin female sockets | 0.1" pitch, single row of 12: 315-43-112-41-001000 | 4 | $10 | DigiKey |
| MCU pins | Mil-Max pin: 3320-0-00-15-00-00-03-0 | 48 | $5 | DigiKey, LittleKeyboards |
There are also longer .5" pins P/N 3320-1-00-15-00-00-03-0. The nRFMicro wiki has more information on machine pin sockets.
- If you will never use a nice!nano wireless MCU, the common choice is ultra low Mil-Max headers and brass pins. The 48 pins come loose and you need to push them into the sockets to align them in a row before soldering the pins to the MCU, but the MCU sits a few millimeters lower as a result.
| Part | Type | Count | Cost | US Shops |
|---|---|---|---|---|
| Machine pin female sockets | Mil-Max Ultra Low header: 315-43-112-41-003000 | 4 | $10 | SplitKB $2.50 ea, Digi-Key $3.20 ea., Mouser $2.60 ea., LittleKeyboards $2.25 ea. |
| MCU pins | Mil-Max pin: 3320-0-00-15-00-00-03-0 | 48 | $5 | SplitKB, DigiKey, LittleKeyboards |
You'll need switches, keycaps, a USB cable to your computer, and a common TRS cable or a less common TRRS cable to connect the keyboard halves.
| Part | Type | Count | Cost | US Shops |
|---|---|---|---|---|
| Switches | Choc v1 | 48, 52 or 56 | $33 | LittleKeyBoards, MechanicalKeyboards, SplitKB |
| Keycaps | Choc v1 | 48, 52 or 56 | $19 | MBK: -LittleKeyboards(black/white big kit, Legend, Glow) -SplitKB (colors) MoErgo POM: SplitKB Artisan: Asymplex |
| TRS or TRRS cable | 3.5mm | 1 | $7 |
TripLite 1' angled or straight plastic Keebio 1' and 3', angled or straight Mouser SparkFun 1' angled Hosa CMM-100.8RR 8" angled Teenage Engineering 6" straight Cable Mart 6" angled Search: short 3.5mm TRS cable |
| USB-C cable | 1 | $12 |
Boardsource 3' USB-A to C, very flexible silicon Keebio 3' and 1' USB-C to C Tripp Lite U420-001-RA 1' angle to straight USB-C to C Adafruit 90 degree angle adaptor USB-C to C |
- You do not need a super high speed USB-C cable, the keyboard to computer traffic is small.
It's good to prevent the board from sliding and to separate all the bottom pads and pins from anything conductive or scratchable you put it on. Most just add plastic bump-ons or something like a cut-to-fit mouse pad or kitchen drawer lining. The high tech option is adding a conformal coating or, more low tech, some Plasti-Dip.
| Part | Type | Count | Cost | US Shops |
|---|---|---|---|---|
| Silicon Feet | 2mm such as 3M SJ5302 | about 16 to 30 | $8 | Amazon |
More bump-on options: Hexagons 3.2 or 1.6mm, Dragon Grips .5mm
LEDs add some visual feedback of any modes the keyboard is in.
| Part | Type | Count | Cost | Shops |
|---|---|---|---|---|
| LEDs | SK6812-MINI-E | 10 | $3 | Digi-Key, Keebio, CustomKBD, Adafruit, KeyHive |