IoT-AIO is a wireless adapter for developing IoT applications for Industrial and Building Automation Systems based on the Espressif chipset ESP32. The adapter is compatible with:
- current loop signals (0/4-20 mA)
- voltage signals (0/2-10 V)
- passive sensors (RTD, Strain Gauge,..)
The library allows the implemention of IoT applications that rely on MQTT protocol via WiFi/NB-IoT/LTE Cat-M1 interfaces.
The Iot-AIO wireless adapter is available in two versions developed using KiCAD 5.1 and compatible with:
- ESP32-PICO-KIT v4 - is an ESP32-based mini development board produced by Espressif. The board features integrated Wifi and BLE capabilites.
- FiPy - is an ESP32-based mini development board produced by Pycom. The board features integrated Wifi, BLE, LoRa, Sigfox, NB-IoT and LTE Cat-M1
IoT-AIO relies on the Espressif IoT Development Framework ESP-IDF, the official development framework for the ESP32 chip.
The adapter can be easily configured at run-time via a web interface based on HTML forms. The software configurator can be accessed by connecting to the adapter while in AP mode and typing in the browser the IP address 192.168.1.4. After a succesful change in configuration the wireless adapter will reset. Source code and additional documentation can be found here:
IO pinout (top-down):
- 0: GND
- 1: I- amperometric negative pin
- 2: I+ amperometric positive pin
- 3: AO/V- analog output/voltmetric negative pin
- 4: AI/V+ analog output/voltmetric positive pin
- 5: 12 V power supply (use input resistor 120 Ω / 1.5 W for 24 V input)
The working mode of the adapter is selected using SW1
- UP: passive mode
- pin 3 -> V-
- pin 4 -> V+
- DOWN: analog IO mode
- pin 3 -> AO
- pin 4 -> AI
When SW1(DOWN) the input mode of the adapter is selected using SW2
- UP: voltage input mode allows for signals in the range 0 to 10 V
- DOWN: current input mode allows for signals in the range 0 to 20 mA
When SW1(DOWN) the output mode of the adapter is selected using SW3(1):
- UP: voltage output mode allows for signals in the range 0 to 10 V
- DOWN: current output mode allows for signals in the range 0 to 20 mA
When SW1(UP) the output mode of the adapter is selected using SW3(2,3)
| Mode | SW3(2) | SW3(3) |
|---|---|---|
| 2-wires | UP | UP |
| 3-wires | UP | DOWN |
| 4-wires | DOWN | DOWN |
The push button BT performs multiple operations depending on the pressure time Tp.
| Pressure Time | Action |
|---|---|
| Tp < 1s | Performs a soft-reset of the adapter |
| 1s < Tp < 5s | Enables the AP mode. If not previously changed, the device will be visible by default with the SSID ESP_<MAC>, where is the MAC address of the adapter network interface in hex format |
| 5s < Tp | Performs a hard-reset of the adapter deleting the previously stored configuration |
We kindly ask academic publications employing based or inspired to IoT-AIO to cite at least one of the following papers:
- M.H. Schraven, C. Guarnieri Calò Carducci, M.A. Baranski, D. Mueller, A. Monti, “Designing a Development Board for Research on IoT Appli-cations in Building Automation Systems,” 36th International Symposiumon Automation and Robotics in Construction (ISARC 2019), Banff,Canada, 2019, pp. 82-90, DOI: 10.22260/ISARC2019/0012
- C. Guarnieri Calò Carducci, A. Monti, M. H. Schraven, M. Schumacher and D. Mueller, “Enabling ESP32-based IoT Applications in Building Automation Systems,” 2019 II Workshop on Metrology for Industry 4.0 and IoT (MetroInd4.0&IoT), Naples, Italy, 2019, pp. 306-311, DOI: 10.1109/METROI4.2019.8792852
2019-2020, Institute for Automation of Complex Power Systems, EONERC
This work is licensed under a Creative Commons Attribution 4.0 International License.
Institute for Automation of Complex Power Systems (ACS)
EON Energy Research Center (EONERC)
RWTH University Aachen, Germany