Introduction: Add an Audio Jack to a Toy
When I was much younger, my brothers and I used to own a Toymax Arcadia "Electronic Skeet Shoot" game system. For reasons now unknown, I decided back in the day that the toy gun would be more fun to play with if I cut its power cord, detaching it from the rest of the system. The newly liberated gun WAS fun to run around with, until my older brother realized I had ruined our new toy. Over time, the game was lost to the ages, either in the dark recesses of our basement, or more likely, a dumpster somewhere.
So, as a Christmas gift this year, I thought it'd be fun to somehow repay the debt of the cut power cord while giving myself a little project to work on. I ordered an old Arcadia system off eBay that was advertised as "Does not turn on. For repair and/or parts."
As it turns out, the system actually worked just fine when it arrived. The first step in this Instructable describes the initial process I went through to check out the power supply.
Step 1: Open It Up and Check the Power!
The game was sold "for repair and/or parts" because it supposedly did not turn on. So the first step was to open the system up and trace the power supply line, hopefully finding an obvious issue along the way. Well, as the pictures above show, it sure looked like power was reaching everywhere it needed to. As it turned out, the system was functioning just fine. The system only powers on when a cartridge is plugged in.
Once I realized the game wasn't in need of repair, I tried to salvage the project by coming up with a simple modification. I decided adding an audio jack to the system would be simple enough to try out.
Step 2: Wire Up the Audio Jack
Because we're not trying to do anything too fancy, it's actually quite simple to add an audio jack to a system like this. Before doing any soldering, I suggest looking over this brief description of switched audio jacks. I had to check the contacts on my jack with a multimeter a few times until I was confident I knew how it worked. Typically, the tip ring sleeve (TRS) of a stereo jack corresponds to left, right, and ground respectively.
*Note: if you're planning to mount the audio jack in a case like I've done here, it may be easier to drill a hole in the case and mount the jack first before doing any soldering.
- As shown in the schematic above, solder a wire between the tip (left channel) and ring (right channel) contacts. The source is mono but the output is stereo so we need to tie the two channels together.
- Solder a wire from the signal (+) pin on the circuit board to one of the pins you tied together in step 1
- Solder a wire from the ground on the circuit board to the ring (ground) contact on the audio jack
- Solder a wire from the speaker's positive (+) pin to one of the normally-closed contacts on the jack
- Solder a wire from the speaker's ground (-) pin to the same ground pin on the jack in step 3.
Okay, you're all done! If you didn't already mount the jack in the casing, drill a hole in the casing and use the jack's nut to secure it in place.
Step 3: Enjoy!
Assuming you've wired the audio jack up correctly, you should be good to go!
- This simple modification is intended to be used with speakers with their own amplifier. If you'd like to drive headphones through this jack, you may have to add an audio amplifier into the circuit. Older headphones are typically higher impedance and the original circuit's audio output may not be able to drive them.
- If the device you're modifying receives its power from the wall, you will likely notice a mains hum when plugging into louder speakers. I didn't try this myself, but it may work to put a simple passive high-pass filter in front of the audio jack. Try out a 1 kΩ resistor with a 10 μF capacitor for a cutoff frequency of 100 Hz.
- This specific Arcadia game system was actually recalled for occasionally bursting into flames... So uh, be careful with that.
Okay, let me know how it goes!
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