The following shopping list is for building everything exactly as I did. For simplicity, shipping and tax are excluded and cost of unused parts is included. Some parts may be sourced more cheaply from vendors on AliExpress and eBay to prioritize cost over shipment time. This also excludes tools that you may need such as screwdrivers and soldering irons. The prices are accurate as of June 1, 2019.
| Item Name | Unit Cost | Quantity | Total Cost |
|---|---|---|---|
| Cherry MX Clear Switches1 | $5.00 | 10 | $50.00 |
| ErgoDox Keycaps | $28.06 | 1 | $28.06 |
| Homing Keycaps | $6.00 | 1 | $6.00 |
| Stabilizer Inserts | $0.50 | 2 | $1.00 |
| Stabilizer Clips | $0.50 | 2 | $1.00 |
| Stabilizer Springs | $0.50 | 2 | $1.00 |
| 1N4148 Diodes | $4.99 | 1 | $4.99 |
| Rubber Feet | $5.99 | 1 | $5.99 |
| 2000mAh Battery | $12.50 | 2 | $25.00 |
| Adafruit nRF52832 Feather2 | $24.95 | 2 | $49.90 |
| Clear Acrylic Case3 | $102.24 | 1 | $102.24 |
| Raspberry Pi Zero W 1.1 | $5.00 | 1 | $5.00 |
| 16GB Micro SD | $2.99 | 1 | $2.99 |
| ErgoBlue PCB (no longer available) | $40.00 | 1 | $40.00 |
The total for the parts above is $323.17. This will be higher or lower depending on the parts and tools that you already have along with other costs such as tax and shipping.
You need to figure out the most appropriate length for the M3 screws based on the thickness of your case. For each hand, I used one 0.22" layer of acrylic for the plate and 6 additional layers of 0.08" for everything else. 20mm was a good length for the M3 screws. Be sure to include the height of the hex nut in calculating the necessary length.
The M2.5 screws and hex nuts are only necessary if you want something to strengthen the connection between the main PCB and the microprocessor board.
76 switches are needed in total. Switches are sold in packs of 10 and it is cheaper to buy 10 packs than 8 packs. ↩
The nRF52832 and nRF52840 boards from Adafruit are often mentioned together because they are very similar. The nRF52840 is newer but uses slightly more energy. For all practical purposes, purchasing either is fine. ↩
The cost for the acrylic case comes from Ponoko, using 0.22" for the plate and 0.08" for all the other layers. This assumes two layer 2 and two layer 4 for each hand. It is much cheaper if you have access to a laser cutter and purchase the acrylic yourself. ↩