Arduino Forum

Using Arduino => LEDs and Multiplexing => Topic started by: peterevans on Aug 20, 2018, 03:11 pm

Title: INA219 current sensor with PWM Ruideng 3W LED driver
Post by: peterevans on Aug 20, 2018, 03:11 pm

I have set up an INA219 to measure current draw and voltage on 3 X1W LEDs connected in parallel. I set up exactly as the INA219 instructions and it seems to be working fine. I also added a PWM dimmer to the power supply and using a pot I can alter the brightness from 0 to full brightness. Now the problems occur when I try to use the INA219 to measure the current between the LEDs and the PWM Ruideng dimmer. If I don't run a ground lead from the power supply back to my Arduino Nano, the LEDs dim like they should but the INA219 readings are erratic and only occasionally show readings that I believe are correct. So I run a ground lead from the negative of the power supply - as it leaves the PWM Ruideng module -back to my Arduino. That makes the readings from the INA219 look good and are very stable, however, I lose all the dimming of my PWM Ruideng module and the pot doesn't make any difference and power to the LEDs jumps to full.
Title: Re: INA219 current sensor with PWM Ruideng 3W LED driver
Post by: Wawa on Aug 21, 2018, 03:19 am
So how did you connect it all up.
You could post a diagram and/or picture.

Is the LED driver powered from a 12volt supply, with three LEDs in series (not parallel).

Did you connect the screw terminals of the INA219 in series with the + wire to the LED driver.

You might not be able to measure a PWM-ed load correctly.
The current sensor takes snapshots, and might take a sample when the LED is off or 100% on, resulting in random current values.

Not sure why you want to measure that LED current.
The PWM value sent to the LED driver is a (x/256) ratio of average LED current draw.
Leo..



Title: Re: INA219 current sensor with PWM Ruideng 3W LED driver
Post by: mfalkvidd on Aug 26, 2018, 10:18 pm
Same question posted (and answered) at https://forum.mysensors.org/topic/9635/ina219-current-sensor-with-pwm-ruideng-3w-led-driver (https://forum.mysensors.org/topic/9635/ina219-current-sensor-with-pwm-ruideng-3w-led-driver)