I can’t really finish my drum machine right now because I am waiting for some 3-way switches to arrive from ebay. I need to learn to stock up. I am way to impatient for this whole “12-21 days shipping from Thailand” thing.
What to do instead?
I picked up this second hand synth the other day. It’s called the Little Composer by Leap Frog.
It’s really more of a musical learning toy for children. It has an 8 note measure that you can adjust each not from low to high C (only in the key of C, of course). The Little Composer has 7 voices. There are three instruments; piano, guitar and violin. There is also a woman voice that tells you what the note is. A, B, C, D, E, F, G… That is really annoying. And finally there is a dog, a cat, and a frog. These only sound good when they are clocked really high or really low.
There are also a bunch of songs too but they are all lame. I suppose that they could be kind of cool clocked real low because the would go for a really long time but I don’t think I will include them in the final build.
The ocatave has no sharps or flats. which is unfortunate. It would be awesome to have a full octave. Of course, if one were to add a pitch bend, one could hit any western key that they wanted.
Naturally, that’s just what I did. I removed the timing resistor and added a pitch bend in series with about 5k ohms (i think),
Here comes the cool part. When you press the play button, this melody-maker only goes through the measure once. This is a real bummer. How is a child suppose to learn music if they can only play one measure at a time. So, I added an LFO from a 555 timer.
It took me a little while to figure out how to make it work. I ended up just running a 10k out of the output from the 555 timer and going strait to the pin on the control circuit that handled the play button. That worked great. I thought I was going to have to do some weird thing with a transistor that I wouldn’t fully understand for the next couple of years. Luckily, that wasn’t the case.
So, if you tune the LFO frequency, as I am doing in the video below, you can get the melody maker to act as a sort of 8 note sequencer. SWEET RIGHT?!
Next, I think I am going to have to add the usual LFO to modulate the pitch and maybe even a tremolo. I’m also waiting on some frequency divider chips from ebay. Maybe one of those will make it in too.