Making our own stylophone

After I saw a design for a DIY stylophone in an electronics magazine, a friend and I made our own. As I recall the original design called for a unijunction transistor for the relaxation oscillator. The UJT oscillator was to get a very short discharge time so that the period would be proportional to the charge time, and therefore controlled by a resistor in an RC circuit. The contact pads which were the "keys" were taps into a resistor chain.

UJTs were expensive so I devised a replacement using a pair of BJTs (conventional transistors). The oscillator was followed by a binary divider to square up the waveform. We made several of these instruments and sold some to friends.

The kid in the first photo is probably my niece. My brother-in-law is at the edge of the picture. In the second photo you see a bit more of the top of the stylophone. The person was a schoolmate whose name is lost to me now.

I remember using my knowledge of the equal tempered scale with its twelfth root of 2 ratio between adjacent semitones to work out the resistor values needed in the chain.

This was probably the first model with a wooden box (cigar or chocolate box). Later versions used a long cigarette pack gift box. Getting hold of suitably sized boxes limited our production capacity.

Introduction to music and scanning 126 negatives

Musician at wedding dinner
The restaurant is Mak Yee
the site of which has
been sold off decades ago

I owned an Instamatic camera, probably my second camera, between my first 120 roll film camera and using a 35mm camera. I seem to remember that my father bought it for me after some pestering from a store in Singapore called CCC Junk Store, which sold goods disposed of by returning expatriates. My father would religiously visit this shop for bargains whenever we visited Singapore. The biggest haul was several crates of 78 rpm records. Most records were classical music. As you can imagine, a long work would be split across many records and this is where the autochanger came in. Of course there were series with missing records and duplicates. All the more fun. The family listened to them for years. It was the basis of my musical education. I remember reading a label and asking my brother What's a Beet-ho-ven? Then: What's a composer? It was only when I was older that I understood that music had composers.

A baptism ceremony
Colours were terribly faded,
it's been 50 years, after all

Anyway I was not looking forward to scanning these negatives as my flatbed scanner software has no setting for 126 film. Also unlike 35 mm strips, which has unexposed film between frames, 126 strips had not just pre-exposed numbers (normal for other formats) and but also pre-exposed frame lines, probably to assist the printing process. The camera could advance accurately between frames because there was only one registration hole per frame for the sensing pin to fall into. Which meant that the frame detection feature of the software wouldn't work. But it turned out to be easy. Following a tip on a forum, I scanned in the whole strip in one go, resulting in 200MB image files, then cut out the various frames with GIMP.