Rack pushbutton panel

A 1U rack panel for a 19 inch rack. Has mounting holes for 8 square pushbuttons, two LED-s and 2 toggle switches.

I made this to have some programmable buttons available in front of the rack, to trigger binary sensors in HomeAssistant. We run some of our theater systems over HomeAssistant, and the panel provides the technician a physical interface to trigger automation from.

Design

The main body of the panel is two identical panel segments attached together, with one rotated 180 degrees. The two pieces connect with internal dowels (included part) and a "clamp" part for more structural integrity. Use plastic glue to fix these parts with the panel body.

The "ears" of the panel are meant to be metal, and you will need to source these separately.

The electronics go directly behind the panel, and are protected by a deep plastic "cover" (also in two parts). The design can't be printed on very small printers (minimum print width needed is 210mm). It fits perfectly on the Prusa MK4S.

Additional parts needed

Pieces that can't be 3d printed - source separately.

Hardware

• square nut, M4 - 8pcs - metal rack ear attachment

• bolt, countersunk, M4 8mm - 8pcs - rack ear attachment

• threaded insert, M2 OD 3mm depth 3MM - 8pcs - hull (back enclosure) attachment

• bolt, countersunk, M2 4mm - 8pcs - hull (back enclosure) attachment

• rack mount ears, Ubiquity Unifi - 2pcs. should have M4 hole spacing of 25mm

• threaded insert, M3 - 4pcs - electronics PCB attachment

• bolt, m3 6mm - 4pcs  - PCB attachment

Electrical

• electronics / PCB + components + connector wires - use provided sample PCB or create your own

• switches - 8pcs - square tactile pushbuttons with LED, 18mm x 18mm

• toggle switch - 2pcs - OD 6mm

• LED in a clip - 2pcs - OD 6mm

• USB C power port female - 1pcs - 14mm x 5mm

• USB C power supply (at least 0.5A)

Printing notes

For the panel, use 3...4 perimeters and 20% infill. The panel should come out not flexible, you want it to bear the pressure of a switch press without flexing.

Electronics

The piece is designed to fit one 170mm x 38mm PCB internally, behind the panel, on standoffs, and inside the enclosure. All of the switch connections and other electronics go inside, and hook up to the PCB for control. I've used an ESP D1 mini for control, with ESPHome as the software.

Included with this design is my PCB design. Use this as an example. It has connectors to accept all connections from switches, LEDs and power, and route those to the ESP for control from ESPHome and Home Assistant. You are welcome to use this PCB as a starting point to design your own version. Keep in mind that I am not a professional electronics engineer or PCB designer, and the PCB will probably contain design mistakes. Use at your own risk and cost.

The example design is intentionally through-hole, using only a few SMD components, so it's entirely possible to hand solder.

The schematics:  https://oshwlab.com/anroots/ruutu10-hass-pdu

You can use JLCPCB (not sponsored) to directly send the design for manufacturing. 

Firmware

Included with the files is example ESPHome firmware. It takes care of initializing all 8 pushbuttons, and triggering automations based on HomeAssistant entity states. Adjust as needed, or use a custom firmware to read simple input sensors.