Having added a few LEDs to the Jack in the Box I decided to see about providing some festive sound track. As I indicated in the first Blog I did find a recordable birthday tag which I hoped to use, so I located this and removed it from the cardboard cover. After a close inspection it appears that the buttons used to record and playback audio are simple mechanical push-to-make contacts. The open circuit value is 2.4V and the closed value is 0V or ground. The sound controller itself seems quite sensitive and will start the record playback on almost any voltage change. I did have a similar tag some time ago that I was using for something else which had some long wires soldered to the switches and these would sometimes be activated by central heating boiler powering up. It was quite scary/weird being in my office and occasionally for no apparent reason it would start to play back, especially as I had recorded 'Hello, is anybody there' in a creepy voice.
The Arduino I am using is a 5V Nano. I tried connecting a digital output from the Nano directly to the switch input using a resistor to drop the voltage, having also connected the two ground voltages and this seemed to work well. So I wired everything together and instantly realised that I had performed the tests with the power to the Arduino turned off as it ran at double speed. So much for trying to be careful. It did make for some interesting voice affects but I thought it might stress the tag and as I only have one this didn't seem like a good idea. So I replaced the resistor with a small potentiometer set half way, to drop the 5V output voltage of the Nano to about 2.5V and this worked satisfactorily. The results can be seen and heard in the video below.
You might also be interested to know that I used some more of the LEDs salvaged from the bathroom vanity mirror to provide background lighting during video. I think it works OK and much better than the table lamp I have previously used.