Expert Topic for experienced builders.
Wired vs Wireless
A relay network uses one communication transport between its bridge and peers. Choose the transport before building and configuring the devices.
| Wireless ESP-NOW | Wired RS485 | |
|---|---|---|
| Hardware | ESP32-based microcontroller on every device | RS485 transceiver and bus connection on every device |
| Physical connection | No cable between bridge and peers | Shared, daisy-chainable wired bus |
| Main advantage | Flexible placement and minimal wiring | More predictable communication in noisy environments |
| Main constraint | Performance varies with distance and local wireless conditions | Requires cabling, electrical design, and termination |
| Security | No encryption or authentication; use in a trusted environment | Physical access to the wired bus is required |
Wireless ESP-NOW
Section titled “Wireless ESP-NOW”ESP-NOW provides a direct, low-latency wireless connection between ESP32-based devices without using a normal Wi-Fi network.
Wireless performance depends on the installation environment. Distance, obstructions, antenna placement, spectrum congestion, and peer count can all affect latency and reliability. Around 10-12 peers is a best-case practical ceiling, not a guaranteed capacity. Test the complete network in the environment where it will operate, including realistic audience or equipment conditions.
ESP-NOW is usually the simpler option for custom relay hardware when every device is ESP32-based and running wires between devices is undesirable.
Relay communication over ESP-NOW does not include encryption or authentication. Use wireless relay communication only in a trusted environment where nearby devices attempting to observe or interfere with communication are not a concern. If that is a concern for your project, use a physically secured wired RS485 network instead.
Wired RS485
Section titled “Wired RS485”RS485 removes dependence on the local wireless environment and allows devices to share a wired bus. It is often the stronger choice for permanent installations and standalone shows where communication predictability matters more than eliminating cables.
A custom RS485 implementation needs:
- A compatible transceiver connected to each microcontroller.
- A common bus wired with the correct polarity and grounding strategy.
- A terminating resistor, typically 120 ohms, connected across the differential A and B signal lines at each of the two devices on the physical ends of the bus. Devices in the middle of the bus should not have termination enabled.
- Firmware pin and transceiver-control configuration matching the custom circuit.
- Appropriate electrical protection and cabling for the installation.
The arrangement of bridge and peers in the physical bus does not determine their software roles. The bridge does not need to be at an end of the chain.
The Using RS485 guide for Bottango control boards gives an example of the connectors, switches, and resistor termination used by Bottango control boards. You can use it as an example to make decisions for your own custom hardware if you want to implement RS485 relay communication hardware yourself, but your custom solution probably will be different enough that you cannot copy it exactly.
After choosing a transport, continue with Enabling Relay Communication in Firmware.