Dead-simple arduino library for "active-low" switches.
Infrared sensor is configured as input and attached as interrupt (when rising). It control another output pin with AC mechanical relay that is "active-low", meaning that relay switch light ON when input is LOW. I wrote it for esp-01, in that case relay go on GPIO_0 with 10K pull-up resistor.
Relay goes OFF with another interrupt, or after defined time if no signal received by IR sensor.
To write a sketch on ESP-01 from ESP32 over USB cable, you need to take care about a few things:
- GPIO_0 on ESP-01 must be LOW before powering to enter boot mode
- RST and CH on ESP-01 must be HIGH for chip to work
- EN pin of ESP32 must be grounded to let us flash ESP-01
- Use different power supply for ESP-01 (+3.3V)
- Connect ESP32 to PC over USB
- Open ArduinoIDE and select generic ESP8826 board
- Compile and upload[*]
[*] if you are having troubles, reset ESP-01 when upload start by pulling RST to the ground
Wiring diagram table to flash ESP-01 from ESP32:
| POWER | ESP-01 | ESP32 | NOTE |
|---|---|---|---|
| x | TX | TX | |
| x | RX | RX | |
| GND | x | EN | disable ESP32 so we can work |
| GND | GPIO_0 | x | ground gpio_0 to enter boot mode |
| +3.3V | Vin | x | |
| +3.3V | CH | x | add pull-up or connect to 3.3V |
| +3.3V | RST | x | add pull-up or connect to 3.3V -> ground it to reset ESP-01 |