I got a talking (actually, singing) greeting card. The card is basically a double-layer of light cardboard with a circuitboard, batteries, and thin speaker sandwiched inside. Opening the card allows two electrical contacts to touch, setting off the song.
The card is basically just an advertisement which I tossed. But the playback mechanism, which I ripped from the card, intrigues me. Can I load my own recording on it?
Let me describe the thing. The board is green and would fit a footprint of about 2"x2". However, it is not strictly square or rectangular; it is sort of Z-shaped. There are 4 watch batteries stuck on it. All the other circuitboard components are tiny, and hardly noticeable. There is a 1.5" diameter, thin black speaker attached to the board by 2 white wires.
I’ve seen versions of these that play “Jingle Bells” and such. I suspect the song is burned into a ROM (read-only memory) chip and thus it would be quite challenging to supply your own.
It does sound like it could be tricky, however, I recently heard about a new magazine called Make which is devoted to hacking, enhancing, and modifying electronics and other commercial products. They have a message board and sounds like it is something people there would know.
Good point. But I should have mentioned that the pre-existing recording is pretty customized – about 10 or 15 secs of a song from some unknown guy’s fledging unknown musical. It’s not Jingle Bells or Happy Birthday, etc.
I can’t imagine that this guy bought more than a few hundred of these micro-players with his song on them. This leads me to suspect this is the type of player that is meant to be custom recorded (and maybe rerecorded) for small production-runs, and not the kind with a permanently burned-in ROM chip. But maybe I’m wrong.
Get out a magnifying glass and start identifying all of those little chips on the board. These things are usually built around a single integrated circuit which does most of the work. Once you identify the part number and manufacturer, you can download the data sheet and see if they are OTP (one time programmable) parts or if they can be erased and re-programmed. If they are programmable, they may require circuit components for programming which are not present on your existing board. You may have to do a bit of hardware hacking to reprogram the devices. It’s also possible that the only way to program the part is to de-solder it from the board, place it on a special board that goes into a prom burner, and solder it back on the board when you are done.
Note that it is also possible (though not likely) that the main IC is built into the speaker assembly.
ISD (http://www.isd.com/) is one of many manufacturers of this type of device. If you poke around on their web site you might get an idea of what you are looking for and how to identify the chips.
Before the spam above is deleted and the thread drops back into obscurity, an aside: as a child, I bought a musical greeting card for the 1984 Olympics (because they were still a high-tech novelty then.) That card is still around, and when I happen across it and open it up, it still plays off the now 33 year old battery. (Okay, that impresses me–even Jesus stopped working after 33 years!)
Off-topic, but I bought a scientific calculator in 1989 for about $8. I still have it, and it’s still on its original set of batteries, 28 years later.
Bit of trivia: the ISD devices that engineer_comp_geek mentions recorded in analog. They used programmable memory cells similar to modern flash memory, but stored an analog value in them. Modern flash makes use of this effect to store 2 or 3 bits reliably–they divide the range into 4 or 8 segments and assign a bit sequence to each one. The greeting card chip (like the ISD1000A) just put the raw value in the cell. It was noisy since the cells couldn’t reliably get within 1/256 of the original value (equivalent to 8-bit audio), let alone to 1/65536 (16-bit audio), but for a greeting card it was sufficient.
A modern card may be made with a massproduced circuit and chip, which may well be the same as those with end user recordable chips…
So you just attach a “record” button, so that it can be told to record from its speaker (speakers work as poor microphones), or a connection to USB or PC…
But anyway you identify the circuit or chip, and work out if its programmable or not.
record yourself circuits are like $5 ready to go . Just tape it to the back of your card and you are ready to record and give.
