Comment by cgrin
1 day ago
The Nano is fine to connect directly because it has diodes on the data pins but the S3 Lite needs a level shifter or it'll eventually stop communicating with the air handler.
1 day ago
The Nano is fine to connect directly because it has diodes on the data pins but the S3 Lite needs a level shifter or it'll eventually stop communicating with the air handler.
yeah came here to say this, I have my mini splits set up on the S3 light with level shifters, not worth skipping because they'll end up failing on you - requires a little soldering but nothing complicated
wiring:
1. Mini split black (GND) → ATOM G
2. ATOM spare G → shifter GND (either row)
3. Mini split red (5V) → ATOM 5V
4. ATOM spare 5V → shifter HV ref
5. ATOM 3V3 → shifter LV ref
6. Mini split yellow → shifter HV1
7. Shifter LV1 → ATOM (G2 / GPIO2)
8. Mini split white → shifter HV2
9. Shifter LV2 → ATOM (G1 / GPIO1)
if the gpio ends up being reversed you can handle it in software