The ACDU is a unit that contains one power output for a DC motor or other DC load, two digital 12V inputs, one analog input, and a connector for an OLED display. Additionally, it can connect to DS18B20 temperature sensors (up to five in total).
This configuration makes it suitable for automation tasks such as:
- DC drive (DC motor with limit switches)
- Thermostat (relay connected to the output)
- Automatic water refill (solenoid valve with float switches)
- Smart timers
- Power supply: 9–15 V DC with reverse voltage protection and battery undervoltage protection
- SoC ESP32-WROVER-IE (supports BT and WiFi communication)
- Driver DRV8220 for DC load control, max. load current 1,6 A
- Two 12V inputs with short-circuit protection
- One analog input, intended for 2-wire sensors, e.g., NTC 100k temperature sensors, photoresistors
- One-wire interface for up to 5 DS18B20 temperature sensors
- Three push buttons, connector for external 3-button keyboard (shared signals)
- One connector for an I2C OLED display
- Connect ESP-PROG programmer to the 6pin connector (blue).
- Connect peripherals.
- Power source (9–15 V DC) to – and + terminals.
- Motor (or other DC load) to "M" terminals (the polarity does not matter).
- (optional) SW1 (standard limit switch), polarity does not matter.
- (optional) SW2 (standard limit switch), polarity does not matter.
- (optional) PR – photoresistor. The PR value should be between 30 and 90 kΩ.
- Attach jumper JP1 (connect pins). With jumper ON, the flashing/downloading of the SW is possible.
- Set up the development environment (Arduino IDE, Platformio, etc.)
In the Arduino IDE, select the board and COM port as shown in the image below.
Also, install the ACDU library via the library manager, as shown in the image below.
When using the ESP-PROG programmer, there are typically two available COM ports. Therefore, always select the one with the higher number.
In the Platformio IDE, set up board and COM port in platformio.ini file:
[env:acdu]
platform = espressif32
framework = arduino
board = esp32dev
upload_port = COM4Please note that the COM port number may vary. When using the ESP-PROG programmer, there are typically two available COM ports. Therefore, always select the one with the higher number.
We have prepared a PlatformIO project template which you can modify for your needs.
A DC load (such as motors, relays, solenoid valves, heating elements etc.) with a current of max. 1.6 A can be connected to the power output (M).
The DRV8220 driver uses PWM mode and allows changing the direction of rotation of the DC motor, braking, and coasting. Three signals are used for control - nSleep, IN1, and IN2. The motor is connected to OUT1 and OUT2.
| nSLEEP | IN1 | IN2 | OUT1 | OUT2 | DESCRIPTION |
|---|---|---|---|---|---|
| 0 | X | X | Hi-Z | Hi-Z | Low-power sleep mode |
| 1 | 0 | 0 | Hi-Z | Hi-Z | Coast (H-bridge Hi-Z)/low-power automatic sleep mode |
| 1 | 0 | 1 | L | H | Reverse (OUT2 → OUT1) |
| 1 | 1 | 0 | H | L | Forward (OUT1 → OUT2) |
| 1 | 1 | 1 | L | L | Brake (low-side slow decay) |
The ACDU also allows to measure the load current. The lowest measurable current is ~150 mA. The current is measured using the voltage at the analog input A0 (SENSOR_VP). The voltage to current conversion is
These inputs are inteded for pushbuttons, limit switches, float switches etc. Do not connect external signals/voltage to these inputs.
Input PR is intended for variable-resistance 2-wire sensors, e.g., NTC 100k temperature sensors and photoresistors. One screw terminal is connected to 12 V via a 60 kΩ pull-up resistor and to GND (ground) via a 750 kΩ resistor. The second screw terminal is connected to the ground. With nothing connected, expect a non-zero value on the ADC.
ACDU supports micro SD cards; the slot is on the bottom side of the board. Please note that some versions of the ACDU do not have a microSD card slot fitted. The communication is done via the SPI serial interface.
Important: For the communication to work properly, it is necessary to remove the JP1 jumper.
| Signal | ESP GPIO |
|---|---|
| 1-Wire (for DS18B20 temperature sensors) | 18 |
| I2C SDA (for SSD1306 OLED display) | 25 |
| I2C SCL | 26 |
| SPI MISO (for SD card) | 2 |
| SPI MOSI | 15 |
| SPI SCK | 14 |
| SPI CS | 13 |
| PUSHBUTTON LEFT | 23 |
| PUSHBUTTON MIDDLE | 22 |
| PUSHBUTTON RIGHT | 21 |
| LIMIT SWITCH #1 | 34 |
| LIMIT SWITCH #2 | 35 |
| ANALOG IN #1 (CURRENT MEASUREMENT) | A0 (36) |
| ANALOG IN #2 (LIGHT MEASUREMENT) | A3 (39) |
| MOTOR DRIVER NSLEEP | 0 |
| MOTOR DRIVER IN1 | 27 |
| MOTOR DRIVER IN2 | 19 |
We have advanced custom firmware which is really flexible and supports the following features out-of-the-box:
✅ User interface built using TcMenu
✅ Motor support
✅ Temperature support
✅ Logging to SD card
✅ Network support (DHCP, static assignment)
✅ Date and time support (NTP, timezones, RTC time...)
✅ Automation (various usecases; we add more when needed)
✅ Internationalization (i18n; currently we support English, Czech, Slovak)
✅ Custom Android and iOS app for remote control
✅ ...and more
❌ Home Assistant support is a work-in-progress
It is likely we can save you significant development time. Feel free to reach out.
If you think there is a missing feature in our ACDU unit, or you encounter an issue while using it, feel free to report the issue in this repository. We also offer commercial support. Perhaps if you work on something, we can help you with that.
Copyright (c) 2023-2024 JSC TechMinds. All rights reserved.
Licensed under the Apache-2.0 license.
We hope our ACDU unit has helped you in your project development. You can support our effort to convert coffee and pizza into code with a small donation. Any support is much appreciated.
