2 layers112 × 38 mm
4 layers65 × 56.5 mm
Stathat
skot/stathatRPi HAT for thermostat 24VAC dry contacts
- Size
- 65 × 56.5 mm
- Copper layers
- 4
- Thickness
- 1.6 mm
- Parts
- 45
- Nets
- 54
- Pads
- 145
- Tracks, vias
- 229, 34
- Pours
- 3
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 24 Apr 2026
- Updated
- 8 May 2026
Overview
Stathat is an open-source printed circuit board by skot, from the skot/stathat repository on GitHub, published under the CERN-OHL-S-2.0 licence. It is a 4-layer board of 65 × 56.5 mm with 45 parts on 54 nets, routed with 229 tracks and 34 vias.
It is built around the 74HC14 and LTV-844S. Its parts include 16 resistors, 9 connectors, 5 capacitors, 4 diodes and 2 ICs. It belongs with the home automation and IoT boards of this library.
Main components
2README
readme.mdStatHat
A RPi Hat interface to a 24VAC thermostat.
Thermostat Pins
| Thermostat pin name | Pin symbol | RPi GPIO |
|---|---|---|
| COOL | Y | GPIO17 (physical pin 11) |
| HEAT | W | GPIO16 (physical pin 36) |
| FAN | G | GPIO18 (physical pin 12) |
| HEAT2 | W2 | GPIO19 (physical pin 35) |
| COMMON | C | N/A |
Parts
45| Qty | Value | Footprint | References |
|---|---|---|---|
| 8 | 5k | Resistor_SMD:R_1210_3225Metric | R1, R3, R5, R7, R9, R11, R13, R15 |
| 8 | Conn_01x01 | stathat:63862-1 | J1, J2, J3, J5, J6, J7, J8, J9 |
| 4 | 10k | Resistor_SMD:R_0402_1005Metric | R2, R6, R10, R14 |
| 4 | 2.2k | Resistor_SMD:R_0402_1005Metric | R4, R8, R12, R16 |
| 4 | 2.2uF | Capacitor_SMD:C_0402_1005Metric | C1, C2, C3, C4 |
| 4 | GREEN_LED | LED_SMD:LED_0402_1005Metric | D1, D2, D3, D4 |
| 4 | MountingHole | MountingHole:MountingHole_2.7mm_M2.5 | H1, H2, H3, H4 |
| 1 | 0.1uF | Capacitor_SMD:C_0402_1005Metric | C5 |
| 1 | 74HC14 | Package_SO:SOIC-14_3.9x8.7mm_P1.27mm | U2 |
| 1 | COOL | stathat:TestPoint_Pad_D1.0mm | TP10 |
| 1 | FAN | stathat:TestPoint_Pad_D1.0mm | TP9 |
| 1 | GND | stathat:TestPoint_Pad_D1.0mm | TP13 |
| 1 | HEAT | stathat:TestPoint_Pad_D1.0mm | TP11 |
| 1 | HEAT2 | stathat:TestPoint_Pad_D1.0mm | TP12 |
| 1 | LTV-844S | stathat:OPTO-SMD-16_L19.8-W6.5-P2.54-LS10.2-BL | U4 |
| 1 | Raspberry_Pi_2_3 | stathat:ESQ-120-14-T-D | J4 |
Questions
How big is the Stathat PCB?
It measures 65 × 56.5 mm and has 4 copper layers, 1.6 mm thick.
What parts does the Stathat use?
45 parts, built around the 74HC14 and LTV-844S. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.
Where can I download the Stathat KiCad files?
From the skot/stathat repository on GitHub, at the commit this page was made from: the board is stathat.kicad_pcb and its schematic stathat.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Stathat design in my own project?
Its repository publishes it under the CERN-OHL-S-2.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
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