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Recorder module, 7 LEDs, and headphone jack Answered

I'm working on this project: https://www.instructables.com/id/Legend-of-Zelda-Treasure-chest-with-sound/

This is the stuff I'm using:

9V recorder module: http://www.radioshack.com/product/index.jsp?productId=2102855
SPDT switch: http://www.radioshack.com/product/index.jsp?productId=2049718
7-8 white LEDs: http://www.radioshack.com/product/index.jsp?productId=3060980

I'm adding onto this project a little. The goal is to have the LEDs turn on when the sound starts and turn off after 6-6.5 seconds (while the sound is still playing, just before the duh duh duh duh!).

I know the 9v battery isn't going to be enough. Somehow I need to introduce more power to light the LEDs to full capacity, but not overload the recorder module after the lights power off.

Does anyone know what part(s) I need to make the light off delay work? 

I also need to find a way to line up the LEDS evenly along an 8" (width) by 1-1/2" area. I was thinking soldering to two strips of metal for positive and negative (two pieces separated with silicone rubber).

Will my strategy for lining up the LED's along the back work? Any suggestions?

I would also like to replace the speaker with a female headphone jack so I can easily record the sound without background noise.

This article (http://kipkay.com/wp-content/plugins/download-monitor/download.php?id=10) also uses the same audio recorder and suggests it's as simple as wiring the jack to the positive/negative wires stating you can use a microphone or plug it into your computer.

Isn't a headphone jack on a computer powered, whereas headphones are not? I would think the recorder module is already supplying its own power for recording. Wouldn't the power from the headphone jack potentially overload the recorder circuit?

So is it OK to wire a female headphone jack to the positive/negative wires on the recorder module without a resistor?

Any insight you guys could provide would be appreciated! Thanks!



6 years ago

What you say makes a lot of sense. After thinking about it, it probably would make more sense to just keep the light on. A delay would just make things more complicated.

Thank you for your help!


6 years ago

Why a delay system. When the box is opened a switch is released turning on the sound. Why not wire the LEDs to the switch so they stay on for as long as the box is open?

The way you have it would require each LED to have a 330 Ohm resistor attached so the battery wouldn't blow them out. I think a better way of wiring it would be in a Series Parallel circuit. It will use less components. Connect 3 wires up in series. Then another 3 wires up in series. (i.e. positive to negative in a chain). Solder the last one to a 330 ohm resistor. A 300 Ohm resistor would be fine. Now take the positive end of each group and wire them together. Then take the negative end of each group and wire them together. You may want to give the LEDs there own 9V battery. For better overall battery life a 6 pack of AA batteries would be better.

Connecting the recorder to the PC's headphone jack isn't going to cause any problems. You can plug it into a CD player or any other item that has audio output without any problems. Just make sure the device outputting the audio doesn't have the sound turned up too high. Otherwise the recording will be so load the sound will be distorted. No need for any kind of resistor on the recorder's input jack. Just check the recording after you make it. If it's too load and disported then run it again with the PC volume lower.