Relay's low voltage side not working properly

Hi all,

I wonder if someone can help on this matter, as I can't find a clear answer.
Summing up: I am using a Teensy LC connected with 4x capacity sensors and 1x Neopixel LED ring (12 pixels). By touching each sensor, the LED ring should change its color and one switch on a 8-Relay-Module should be triggered. On the high voltage side are 4x micro pumps (each needs 12V) located.

My wiring is as follows:

  • 5V USB transfer going to Teensy LC
  • 12V power supply to power the pumps on the high voltage side
  • LED-Ring and VCC low voltage side of the relay are connected to 5V Output Teensy

Each component independently (LED-Ring, Relay, Pumps) works perfectly. When the high voltage side of the relay is not connected to a power supply, then the LED-Ring works as it's supposed to. As soon as the 12V is powering the pumps, the LED-Ring doesn't work (it emits light, but it doesn't change anymore) while the pumps are running. In my initial wiring, I had two different power supplies for each (1) Relay (high voltage side) and (2) Teensy LC (LED-Ring and Relay low voltage side is connected to it)

What I have already tried:

  • Having a common ground by connecting the Teensy LC to the ground of the 12V power supply / also tried it with connecting the Ground of the relays low voltage side to the same ground as the high voltage side
  • Isolating the Board from the relay by connecting the jumper of the relay to an external power source
  • Connecting the Teensy LC (5V), the LED-Ring (5V) and the low voltage side of the relay (5V) to the same power supply as the relays high voltage side (12V) by putting a step down converter (12V to 5V) inbetween

Any ideas?

Thanks a lot!
Nasumi

what are the capacitive sensors?

did you try with a 5V 1A at least wall adapter going to

  • the teensy LC
  • the relays
  • the Led Ring
    (all sharing the same GND)

and a 12V / with suitable Amps for the 4 pumps connected to the High side of the relay

And Don't push high currents through your breadboard

Neopixels pull a lot of current. So do relay coils. It looks as though you will need separate power for at least one of them.

The capacitive sensors are iron wires wrapped around wool.

I tried a wall adapter with 5V 1A for teensyLC/relay/LED Ring but nothing changed, unfortunately.

powering them separately in parallel, not through the teensy?

Get a blank sheet of printer paper and a black ball point pen and draw a schematic of the circuit.
Nobody wants to try to trace lines in a Fritzing. It is counter productive.
List all you loads numerically with there voltage and current. (I don't see any pump current or Neopixel current info) . If you don't know post links for everything except the Teensy.

Yes, I powered them in parallel

I also tried it already - connected the relay to the 12V using a step down converter / 5V only for the LED ring and teensy LC

Hi,
Can you please post an image(s) of your project, so we can see your component layout?

Can you please post a circuit diagram, including power supplies, component names and pin labels?

A hand drawn diagram would be fine.

Thanks.. Tom... :grinning: :+1: :coffee: :australia:

Hi all,

sorry for the late reply and missing schematics!
Here is my wiring:

It finally works! Powering the 5V parts in parallel (Teensy LC + LED-Ring + Relay) didn't work well -> the LED-Ring didn't interact as supposed to. It seemed more stable when the Teensy receives power (in my case by a 5V powerbank) and then the LED-Ring and Relay are both powered in parallel by the board.
But the biggest mistake was running 12V through a breadboard :sweat_smile: thanks @J-M-L !

Good

More than the 12V, that’s probably the high current that was flowing through

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