Hey everyone,

I am attempting to create a circuit where, when a button is pressed, an LED lights up and a tone sounds from a tone generator board that I have. The board takes a negative input. I have it about 95% correct....the problem is, when power is applied, the LED lights at about 50% brightness without the button being pressed. When the button is pressed, the LED illuminates to full brightness.

Here's a schematic of the circuit working as described above:

Here's the tone generator I am using:

Here's a snippet of the button specs I am using:

Can someone help point me in the right direction so the LED is completely off until the button is pressed?

Thanks!
Joe

 

Your schematic is somewhat hard to read. I assume that the red +12V wire does not connect to the other red wire (no dot) - otherwise, the switch is shorting the power supply. The 'T' wires should have dots at the junction to advise the reader of the connection.

What is the part number of the tone generator? It looks like a 5089? If so, which pin are you driving with the switch? The various tone disable inputs turn the tone off when pulled to ground like your schematic shows - Are you switching one of the keyboard matrix pins? What you show is not how I'd expect a 5089 to work.

Assuming a 5089:
It looks like the inputs have internal pullup resistors so that would explain why the LED is dimly on when the switch is open, the pullup resistor feeds some current to the LED.

Controlling it using TONE DISABLE/ :
You might be able to use the alternate contact of the switch to light the LED as the sketch shows but its hard to tell without more info about the pin numbers connections.

If that sounds OK, try it. If not, add some more info to the schematic (Include ALL of the pins in the dwg. )and we'll take it from there.

And if its not a 5089.. most of this doesn't apply probably.
Good luck.

 

Connect the 1k resistor to switch pin 3 instead of pin 1. Connect the LED anode to the IC Vdd supply (+5V?) instead of pin 3.