Power Monitoring Sensor

Updated: 6/28/2025 Words: 0 words Reading time: 0 minutes

An ammeter is an instrument used to measure the magnitude of current in a circuit. Measuring current is very important in electronic products, such as in battery management systems, where real-time monitoring of charge and discharge current prevents overcurrent/short circuit. Monitoring the current of electrical appliances can monitor energy consumption, achieve energy saving or fault early warning. Car light monitoring is achieved by detecting current: current is stable during normal operation, and zero when open-circuited, thereby judging the status of car lights.

Preparation

Hardware

Hardware	Description	Image
Creative Box Platform
ASC712	Taobao Purchase Link, Hall effect-based power monitoring sensor, select the required current measurement range.
480 Ohm Resistor	Taobao Purchase Link. Does not need to be exactly the same, values around 480 ohms are acceptable.
Dupont Wires	Taobao Purchase Link, please select male-to-female type

Appliance preparation:

Note

Besides using LED strips as appliances, you can also use other electrical devices, such as motors, etc.

Hardware	Description	Image
Power Signal Module	Included with Creative Box purchase
WS2812 LED Strip	Taobao Purchase Link, you can control the color of each LED on the strip

Software

Software	Link	Description
Current Monitoring App	Link	Official frontend application, can be loaded and used directly through the console.
LED Strip Control App	Link	Official frontend application, can be loaded and used directly through the console.

Connection

Connection
▀ Connect the ASC712 module signal output to any pin on the platform. The diagram shows platform pin 4 connected.
▀ Connect the ASC712 module ground signal to the platform ground.
▀ Connect the ASC712 module power signal to the platform's 5V power supply.
▀ Connect the ASC712's terminal to the measurement signal. Here, one end connects to the 5V power supply, and the other end connects to the LED strip's power input.

For LED strip connection methods, please refer to: LED Strip

Usage

Note

When clicking the start button, the application will calibrate the ASC712 module, ensuring that the appliance is turned off.

The following step screenshots are from the mobile web, please use a computer browser for better results.

Open the Creative Box console and load the Current Monitoring application from the sensor applications. Enter the application, select the measurement module ASC712, the pin number connected to the Creative Box for signal output, and the range of the ASC721 module used. Clicking the start button will...

Creative Box Console	Load Application	Select Measurement Module, Pin Number, and Range	Start Current Monitoring	Light up 100 LEDs in the LED Strip App, select blue.

Light up 100 LEDs in the LED Strip App, select blue.

Principles

ACS712 Power Monitoring Module

Measuring DC current is straightforward; AC current measurement is more complex because the current direction and voltage are constantly changing.

ASC712 is a current monitoring module based on a Hall sensor. When current passes through a conductor, a magnetic field is applied perpendicular to the current direction, creating a potential difference across the sides of the conductor. This voltage is called Hall voltage. ASC712 can apply a magnetic field and monitor the Hall voltage. As current intensity increases, the corresponding Hall voltage also increases; conversely, as current intensity decreases, the corresponding Hall voltage also decreases. ASC712 outputs a 0-5V voltage at the output pin to represent the current magnitude. When the current is 0, ASC712 will output a zero-point voltage of 5V/2, which is 2.5V.

The platform's ADC range is 0-3.1V, while ASC712's zero-point voltage is 2.5V, and different range ASC712s have different sensitivities. Referring to the datasheet screenshot below, for a 5A range ASC712, its sensitivity is 185mV/A, meaning a change of 185mV in output voltage corresponds to 1A of current.

Range	Sensitivity
5A	185mV/A
20A	100mV/A
30A	66mV/A

Taking the 5A range ASC712 as an example, through calculation, its voltage output range is between 1.575V and 3.425V. Due to the platform ADC range limit (0-3.1V), the ADC can measure up to 3.1V. Therefore, without external voltage divider resistors, the platform can monitor a maximum of 3.25A of forward current. Of course, for reverse current, the platform can monitor its full range, which is -5A.

For a 20A range ASC712, the platform can monitor a maximum of 6A of forward current; for a 30A range ASC712, the platform can monitor a maximum of 9A of forward current.

Reference Datasheet Download

Datasheet Download	Link
ACS712	Link

• There are three different models, corresponding to 5A, 20A, and 30A ranges respectively.