The electrical current shunt board combined with an ESP8266 D1-mini microcontroller and the Arduino library SensorWLED make it easy to measure up to 10 Ampere with reasonable accuracy.
Tracking fast-changing Neopixel pixel currents with the WLED DC sensor is a perfect application example. That was the specific design objective. Unfortunately, the varying current level is often only roughly estimated in WLED projects.
The female header breaks out I2C-signals, VCC (3.3V), and GND for a small OLED display. Alternatively, use a larger SPI-based display or send data with WiFi for remote monitoring.
The Texas Instrument INAx180 low- and high-side voltage output current-sense amplifier has the following main characteristics.
- Common-mode range (V CM ): –0.2 V to +26 V
- Output slew rate: 2 V/μs
- Offset voltage: ±150 μV (maximum) at V CM = 0 V ±500 μV (maximum) at V CM = 12 V
- Accuracy: ±1% gain error (maximum) 1-μV/°C offset drift (maximum)
- Gain: 200V/V
- Quiescent current: 260 μA maximum
The current sense resistor (1.5 mOhm, 1%, 50ppm/C) handles currents up to 10A.
- Wemos/Lolin D1-mini ESP8266 microcontroller. The WLED sensor becomes a shield on top of the controller.
- Female header pins for the microcontroller.
- Display (I2C interface) for current readings.
Measured values are not strictly required to display on an OLED since they are accessible through a web browser. Neither is the usage of an ESP8266. Instead, use the sensor with, for example, ESP32 and wire the I2C signals from the sensor to the microcontroller. Pull-up resistors, e.g., <=3.3 kOhm to VCC on the I2C signals, are recommended.
Please, see the documentation for the Arduino library SensorWLED.
The fabricated two-layer board has the dimensions of 26.0 x 34.2 mm (1.02"x1.35").
| parameter | imperial | metric |
|---|---|---|
| board material | FR4 | FR4 |
| board thickness | 39 mil | 1.0 mm |
| copper layer thickness | 1.4 mil | 35 um |
| board color | purple | purple |
| board text | white | white |
| board weight | 2.82 oz | 80 gram |
The WLED current sensor board will be available fully assembled when released.
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