retrointerfacing

Using a telephone retro-interface and Arduino wav-shield-derivative a box has been build which allows you to use an old rotary phone as standalone dial-a-song system. This makes an excellent CD-pre-listening device for our CD-sales stand at concerts.

The system is fully documented (including schematics, software, PCB layout) on the wiki. Although numerous designs have been made where the innards of rotary telephones have been replaced by other electronics (birthday card sound chip, GSM telephone), this project has a completely different approach. No changes to the telephone have been made. The phonebox generates line-voltage, even the 90V 20Hz ringer voltage. A sound input/output is added for line level signals. The box is powered using 12V dc, so mobile operation is possible.

The idea (accidentally re-invented) is not new - so it is in two respects a retro-interface From wikipedia: Established by rock band They Might Be Giants (TMBG), Dial-A-Song consisted of an answering machine with a tape of the band playing various songs. The machine played one track at a time, ranging from demos and uncompleted work to fake advertisements the band had created.

So basically this design is your dial-a-song-in-a-box….

This is probably a very very rare issue that needed a special solution. Anyway. If somebody out there find him or herself in the same situation, read on, remember, and know what to do.

If you’re out on a stage, with a folk-band, you have your basic tools, the harp is seriously in need of tuning, but, alas, no tuning key can be found, do this:

Listening to electromagnetic fields is easy and fun (you can actually listen if a wire is ‘live’ or not, provided AC current is running through). Especially laptop computers emit a lot of EM noise in audible range.

Use the electronics of an old walkman. Perhaps you have the guts of a walkman lying around, perhaps the motor and wheels have already been used to make a solar roller or whatever. Anyway, if the electronics are still in one piece, you can simply hook them up to a pair of headphones or connect them to the audio input of a computer (recording using Audacity). Anyway.. go ahead and discover the enormous amount of fluctuating fields around you … EM field sounds from laptop or see the recording in progress on youtube…

I remembered reading once that manufacturers of electric candles had been using melody-card chips as LED drivers, causing these candles unseeingly to emit music. In order to ‘audify’ this optical sounds, I connected a BPW34 diode (with large Silicon cell, so it actually generates a voltage) to a jack chassis and hooked it up to an amplifier. The following youtube clip shows the results. Strange enough in this candle no beautiful (Christmas) melodies, but a strange repetitive crazy synth….

I’m currently living in an apartment without the possibilities of building a permanent recording studio. (In one of the previous houses I lived in I had a room specially modified for recording and practicing) I still want to be able now and then to record instruments without the sound of my concrete square room, without the high ‘ringing’ noise you get when clapping your hands together.

From the acoustic insulation of this previous room I had some very thick foam mats for soundproofing left, as well as a couple of sheets of acoustic dampening foam, each 50 x 100 cm wide. I mounted them into wooden boxes with hinges in between, so I have as sort of portable sound-deadening room divider. Here are some pictures as well as the ‘before - after’ recordings of a cajon. On a normal set of speakers the effect is not so clear, but try it with headphones Without or With screen