MK107 sequencer

How to turn a cheap Velleman LED kit into a simple eight-note analogue voltage sequencer for a synthesizer, WSG etc. The whole thing could be built for under £10 and has a novel function for playing subsets of the selected notes for 'related' arpeggios. This electronic music project comes to you from the bench of Mirlitronics, Inc., suppliers of low-tech gadgetry to "The Mirlitrons" - check us out on iTunes.

Category:

Science & Technology

Tags:

• sequencer
• synthesizer
• voltage control
• VCO

[MirlitronOne]

Why not? For portability. Convenience. And to avoid encouraging some of the visitors here to blow it up or to electrocute themselves.

[MirlitronOne]

You wouldn't want the rate to go down to 0 bpm though, or all the action will be in the last few degrees of the pot. 60 - 280 is more reasonable.

Sorry, I don't have a reference for the Bongotnik circuit. All I can tell you is that it was based on "The Audio Artist Sound Effects Machine" by James Barbarello, published in Popular Electronics in the mid 1970s - early 1980s. Maybe there are indexes online where you can track it down.

[MirlitronOne]

Granoj1's comment was copied to me and didn't seem like spam, so here goes: the components that determine the clock rate are C3 (the 1 uF capacitor) and the variable resistor. You can limit the lowest and highest rates with resistors either side of it. R10 already limits the highest rate in the original circuit. The clock is a 555 timer, so the 555 data sheet or any good electronics primer will tell you how the frequency depends on the resistor and capacitor values.

[MirlitronOne]

No - the 4015 chip has no reset line.

[MirlitronOne]

No, I'm secretly MirlitronOne. Ooops.



[MirlitronOne]

Yep, that's all you need. The only addition to mine was a switch and limiting resistors to ensure that the output does not exceed any input limits on the circuitry to which it is attached. Normally, this won't be a problem, especially if you are careful not to turn the output (range) pot higher than is needed to give you the pitch range required.

[ohnoitshoward]

thank you for the wonderful clear instructions. many thanks!

[KorgAddict1]

Really cool! I'm curious as to why you decided to keep the circuit running on a 9v battery instead of replacing it with a 9v universal power supply?

[robman80808]

Thanks for posting this. Going to give it a go (newbie). Could you please answer a couple of questions for me to avoid toasting my Monotron? 1. Is the gate out wired without a ground? It looks like there is only one wire in the video. 2. What resistors did you use to ensure only a 5v max output? 3. I'm new to diodes - Maplin has a Schottky Rectifier Diode. Is that the one I need? If not, is there another product at Maplin I could use (no AO91 on there).

Many many thanks!

Rob

[granoj1]

Clever thinking! Is there any way of limiting the rate of the sequencer? What I`m after is getting the sequencer to a more musical range something like 0-280 bpm. I dont`t really care about noise as plain noise but when it`s rhythmic things get interesting. By limiting the range you would also get more precise control over the sequencer I think. Also, I love your Bongotnik but the link to Synthdiy article is dead. Could you advice me where to find the schematic? Thanks!

[scttcmpbll]

can this be set up to be less than 8 steps like a 4017?