Hallmark Card Control Issue

Hey everyone. As many have already done, I’m trying to control a Hallmark Card that plays “Celebration” and has 3 button batteries which measure combined 4.5v.

I successfully disassembled the card and re-wired it so I can control from 4.5v with just two wires. Worth noting that the card also had 3 LED fiber optic lights, but I’m not using them and just cut those wires.

When I try to power from the Arduino (using a digital pin high), the speaker makes a constant skipping sound. It’s an older Arduino Yun, but I doubt that is relevant. My gut tells me it’s not getting enough current. Voltage out on Arduino measures the same as the 3 button cells.

Any thoughts?

Thanks,

John

Friend says to try putting a 100 uf electrolytic cap and also a .01 uf cap across the power in leads to the card. That may stabilize the voltage.

Going to try this next

SOLVED - Got it to work by putting a single 10 uf cap between + and GND. If I had a scope handy, it would have been clear that the DC voltage is very noisy.

siliconghost:
SOLVED - Got it to work by putting a single 10 uf cap between + and GND. If I had a scope handy, it would have been clear that the DC voltage is very noisy.

It's more likely the very limited current your output pin can deliver that is the real cause of the problem.