Push button with LED - Page 1
Forum section: electronics / projects

author: thisisliam
author_rank: Contributor
timestamp: January 26, 2019, 02:52:58 am
content: Hi allI have a SPDT push button switch that has an LED installed. I'm attempting to get the LED to illuminate when pushed only AND have the switch complete the audio circuit at the same time. When the button is not actuated, no LED and no circuit. Please see the attached diagram for the lug configuration. The audio circuit successfully completes when the + wire is soldered to N.O. and the - wire is soldered to COMM. Attempting to add the LED into the mix is where I'm struggling.Currently I've tried a few combinations, but haven't been able to achieve what I need. The latest attempts:* N.O. > LED+, + wire to COMM, and - wire to LED- (LED illuminates when pushed, LED off when not pushed, no audio circuit made when pushed)* LED+ > N.O., LED- > COMM, + wire > N.O., - wire > COMM (LED illuminates when button is not pushed, goes off when pushed, audio circuit made when pushed).I'm starting to think the design of the switch won't allow for what I'm trying to do (maybe a DPDT switch is what I should've bought?)Input greatly appreciated!

author: ArthurDent
author_rank: Super Contributor
timestamp: January 26, 2019, 03:20:27 am
content: A DPDT switch is what you need.

author: thisisliam
author_rank: Contributor
timestamp: January 26, 2019, 03:25:08 am
content: *sigh* I figured as much. Thank you for verifying!

author: Zero999
author_rank: Super Contributor
timestamp: January 26, 2019, 01:13:58 pm
content: If you can't get a switch in the same format but DPDT, then you could use the switch to switch the LED and a relay, which is used to control the audio circuit.

author: thisisliam
author_rank: Contributor
timestamp: April 28, 2019, 05:51:58 pm
content: Quote from: ArthurDent on January 26, 2019, 03:20:27 amRevisiting this thread.I have tracked down and ordered the DPDT version of the push button w/ LED switch.@ArthurDent - curious... the diagram you posted shows a DPDT switch but you've labeled it as if I was wiring SPDT. Am I missing something here? I would've assumed that needing a DPDT would mean I would use one set of poles for creating the circuit for the LED to illuminate when pushed, and the other set of poles to create the circuit for the initial function of the switch...Thanks for the help!

author: OM222O
author_rank: Frequent Contributor
timestamp: April 28, 2019, 06:09:26 pm
content: I'm surprised nobody recommended this, it's actually extremely simple:Connect Led+ to NOconnect LED- to a current limiting resistor and then to the ground.Power for audio circuit (I'm assuming from a battery or power supply) goes to the common pin.And the NO gets connected to the audio circuit power as well.this way when you power up the audio circuit (assuming that's how you actually use the device, some schematic would be great) when the NO is connected to the power supply / battery, the LED is connected via the resistor, and the power is also connected to the audio circuit. Now if that's not your application and you're trying to power the LED from the audio signal itself, you will introduce tons on noise on your audio singal, not to mention variable brightness of the led, even *IF* the audio signal reaches something like 3v to begin with!