serin labsCN105 Cable and ESP32 Parts List
The Pre-Assembled Option
The Serin Controller ships pre-assembled with the CN105 cable included, ready to flash the firmware of your choice: ESPHome, Apple Home, or Google Home & Alexa compatible. The rest of this page covers building your own.
1. CN105-to-Grove Cable (Required)
This cable connects the ESP32 board to your Mitsubishi unit's CN105 service port. It is a JST PAP-05V-S housing on the HVAC side and a Grove HY2.0-4P connector on the board side. Crimp your own from the parts below, or skip the crimping with a ready-made cable (from $8).
Build Your Own
You can assemble a cable from these parts. See the wiring reference for the pinout.
| Part | Description | Link |
|---|---|---|
| JST PAP-05V-S | 5-pin connector housing (CN105 / HVAC side) | DigiKey |
| Grove HY2.0-4P cable | 4-pin connector with wire (device side) | DigiKey |
You will also need crimp terminals (JST SPHD-002T-P0.5) and a crimping tool, or you can solder the wires directly.
Cable Length: Metal-Bodied Air Handlers
Multi-position ducted air handlers (SVZ, MVZ, PEAD, PVA) have a sheet-metal cabinet that can weaken WiFi. A longer cable (50 cm rather than the standard length) lets you route the connection out of the cabinet and mount the controller on the insulated plenum or ductwork outside it, where the signal is stronger. The pinout is identical; only the length changes. Pick the 50 cm option when buying the cable if this is your setup.
2. ESP32 Board (Required)
Choose one of the two supported boards. Both work with the ESPHome, Apple Home, and Google Home & Alexa compatible firmware.
Detailed spec comparison
| NanoC6 | Atom S3 Lite | |
|---|---|---|
| Chip | ESP32-C6 (RISC-V, 160 MHz) | ESP32-S3 (dual-core, 240 MHz) |
| WiFi | WiFi 6 (802.11ax, 2.4 GHz) | WiFi 4 (802.11n, 2.4 GHz) |
| Size | 23.5 × 12 × 12.5 mm | 24 × 24 × 13 mm |
| USB | USB-C | USB-C |
| Grove port | HY2.0-4P | HY2.0-4P |
| Button | Yes | Yes |
| ESPHome | Full support | Full support |
| HomeKit | Full support | Full support |
| Google Home & Alexa | Supported (beta) | Supported (beta) |
Both boards have more than enough processing power for this firmware. The NanoC6 is recommended for most setups due to its smaller size and Wi-Fi 6 radio, which provides a more stable connection when enclosed in the sheet metal of HVAC units.
3. USB-C Data Cable (For Flashing)
Needed once to flash the firmware. A cable used to sync a phone usually works.
- Must be a data cable, not a charge-only cable.
- Test it by connecting a phone; if your computer detects it, the cable works.
Shopping List
| Item | Where to Buy |
|---|---|
| CN105-to-Grove Cable | Buy ready-made or DigiKey (DIY parts) |
| ESP32 Board (NanoC6 or Atom S3 Lite) | M5Stack Store |
| USB-C Data Cable | Likely already on hand |
Multiple Indoor Units
You need one board and one cable per indoor head; each indoor unit has its own CN105 port. A 3-zone system needs three of everything above.
Optional accessories
- USB-C data cable: only needed for initial flashing; after that, updates are done over WiFi (OTA).
- Label maker or tape: helpful for labeling cables in multi-unit installations.
- USB-C power supply: for powering the board on a bench to test it before installation.
Next Steps
- Check your model: type your model number for an instant compatibility answer.
- Flash the firmware: install ESPHome, Apple Home, or Google Home & Alexa compatible firmware from your browser.
- Wire it up: connect the cable to your HVAC unit.
Links are provided for convenience and are not affiliate links.