Constructing a Jaycar MIDI: Tom's other adventure in electronicland

I began work on the Jaycar MIDI theremin kit last night.

All I can say is, this kit is definitely not for beginners. There are a zillion little tiny pins to solder in place very close to each other. I've gotten fairly adept at soldering, and I still had to de-solder some of them and redo the work. The construction is fairly difficult, and the instructions are particularly vague in some parts. (There's about a paragraph of text to describe how to assemble one entire circuit board, for example.) I'm managing okay because I know what I'm doing at this point and have professional advice on hand anyway, but I expect a beginner would be completely lost.

The kit has three circuit boards. One is pre-assembled, which is the LCD panel. I finished the easier of the other two last night, and made a small start on the third, which is the main board. The main board of the Jaycar MIDI theremin alone is significantly more complex than the entirety of the Jaycar Silicon Chip Theremin Mark 1.

Almost all of the connectors and controls are also soldered directly onto the boards. This makes things somewhat difficult if you want to replace the cheap plastic case with something significantly different. I haven't decided how to deal with that yet.

i'd have to agree with you there Tom the instructions are severly lacking in detail, its reasonably hard to solder too.
I'm giong to make new antennas for mine, do they have to be hollow pipe or can the be solid?

hi,

i built this kit last year, the instructions are best augmented by extensive reading of the forum here if you plan to make a custom case and antennae. i found this article by Abdulkn most useful:

http://www.thereminworld.com/article.asp?id=12

it deals with the standard jaycar kit, but the basic principles apply and the section on making antennae is ingenious.

i've posted it before but here's a photo of my MIDI theremin showing my DIY casing and antennae:

[img]http://wildchurch.com/miditheremin1.jpg[/img]

the antennae are fashioned from aluminium tubing.

regards

Thanks for the help. I had seen that article, but more pointers to it are a good thing.

Did you have to make a custom coil for the MIDI instrument to use custom antennas?

i experimented with some coils to linearize responses of the antennae. i didn't have the means to hand-wind my own effeectively so i tried various coils extracted from junk radios etc. finally i found having a telescopic antennae for the pitch control to be most convenient: it's constructed from 2 gauges of aluminium tubing. the volume control has a coil to widen the control range. overall i find this solution seems to work well enough. i have to say the MIDI theremin is a great deal of fun, but i don't really use it as anything other than a gestural controller for effects/synth parameters. my 'real' theremin puts it to shame in terms of musical playability, this is largely due to MIDI limitations of pitch bending superimposed over discreet notes.

regards

Unfortunately, I've never had a telescoping antenna that I didn't break, so I've come to hate the things over the years. I guess I'll have to deal with hand winding coils.

I have several goals for the thing. Partly, I'm just curious about it. Partly, I want to see how much I can improve the instrument through software which I will create. (I'll give it away when I'm done if it's any good.) And partly, I want to use it as a gestural controller to make un-theremin-like sounds.

I'm upset that Jaycar seems to have discontinued the model. I was really hoping my explorations could give it new reasons for popularity. And, now I can't buy another one in case the first one dies.