Circuit that will play audio when a desk lamp is turned on

Thread Starter

Wombat

Joined Jul 5, 2007
9
My girlfriend is a big hunger games fan, and has a lamp that uses the 3 books as the base. I would like to build something that will play the hunger games 'whistle' when the lamp is turned on. I could uses something like this AdaFruit sound board as the base of the project, but how could I implement the trigger? I'm thinking I could use a usb transformer to power the project.

Has anyone tried something like this? Can you point me in the right direction?

Thanks!
 

#12

Joined Nov 30, 2010
18,210
Get a 6 outlet power strip and plug the lamp and the sound device into it. Turn on one switch and both will start at the same time.
 

Thread Starter

Wombat

Joined Jul 5, 2007
9
Well now you're just making me feel silly.

What about triggering the playback on powerup? The Adafruit board I referenced uses a ground trigger. I've seen projects that uses a 555 to trigger on powerup, but it triggers high, not ground.
 

crutschow

Joined Mar 14, 2008
25,634
What about triggering the playback on powerup? The Adafruit board I referenced uses a ground trigger.
Here's a simple circuit that holds the input low for about a half second upon the application of power.
It says a normal trigger is 125ms low, but It may take longer than that on bootup.
If so, just increase the value of C1.

upload_2017-2-23_9-42-15.png
 

MisterBill2

Joined Jan 23, 2018
7,257
My girlfriend is a big hunger games fan, and has a lamp that uses the 3 books as the base. I would like to build something that will play the hunger games 'whistle' when the lamp is turned on. I could uses something like this AdaFruit sound board as the base of the project, but how could I implement the trigger? I'm thinking I could use a usb transformer to power the project.

Has anyone tried something like this? Can you point me in the right direction?

Thanks!
A quite simple method of providing a constant "ON" signal when the light is on, and provides good isolation from the lamp power, is to use a phototransistor that looks at the lamp fairly close. With the lamp illuminated it will be saturated and it can pull down fairly close to ground, with the light off it will have several K-ohms resistance.Just use instant epoxy to mount it behind the lamp so that it gets light but does not make a shadow. Cheap, easy, effective, and removable when she gets bored with it.
 
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