PIN out to replicate push button function?

Other Hardware General Electronics
1

Hi all,

I have a general hardware/electronics question which I'm hoping someone can help with please.

As part of a project I've built I have a set of USB powered RGB fading lights (three LEDs in a cluster) which also have a small push button incorporated into the tiny PCB that they sit on, which cycles through the various mode functions (all lights on, all lights flash, all lights fade, one LED on etc etc).

This push button is a momentary push to make switch with both traces going to a non descript black blob on the PCB. One side of the switch shows at +5v, the other shows at +2.5v.

Both the lights and the Arduino run on a common DC circuit with common ground.

Am I right in thinking that I can have the Arduino act as the switch by having a digital PIN written high momentarily as long as that connects to the +2.5v side of the existing switch, or is it all a bit more complicated than that and a different solution is required?

Am aware I could probably achieve a similar solution with a simple single RGB led using code, but my project has a few other functions in it and I have no PWM pins left!

Would prefer a bit of insight before I charge on in and test it for fear of ruining the (admittedly quite cheap) RGB circuit :smiley:

Thank you :slight_smile:

2

BTW

Always show us a good schematic of your circuit.
Posting images:
https://forum.arduino.cc/index.php?topic=519037.0

3

dynofiend:
Am I right in thinking that I can have the Arduino act as the switch by having a digital PIN written high momentarily as long as that connects to the +2.5v side of the existing switch, or is it all a bit more complicated than that and a different solution is required?

The arduino could be to control the state of a switch (open or closed). And --- what kind of arduino are you using?

4

One side of the switch shows at +5v, the other shows at +2.5v.

Where is your black meter probe connected? Are those readings with the button pressed or not? What do you read with the black probe on one button lead and the red probe on the other button lead with button pressed? Released?

5

Those readings are with red probe to the pins on the switch and black to ground. There is no continuity through the switch when it's not pressed. Admittedly I've not measured the voltage on those wires with the switch pressed though I assumed it would be 5v? I'll do that shortly.

I am using an Arduino Mega.