multi direction sequencer with lm3914

zipzap

Hi everyone
I just came across this link http://www.geocities.com/SiliconValley/Lakes/7156/articl3.htm
now i´m thinking: would it work to build a sequencer from this lm3914 ledmeter driver? It has a single dot mode - only one out beeing active at a time. Which step that is is determined by the voltage at the input of the ic. Normal aplication of this would be a vu-meter for example.
but what if i build a sequencer around it instead? any voltage could than be used to select the step. A triangle lfo would produce a pingpong sequence, rising ramp the normal forward mode, falling ramp a reversemode. random signal would result in random sequence.
the amplitude of the waveform determines how many steps are beeing played. With an offset it could be achiefed that 0v is the center or lowest step.
A sample and hold at the input could possibly be used to sync this to any clock signal.
Sounds possible? If it is i´m sure someone already done it, because it sounds fun to me.

mosc · Posted: Fri Mar 24, 2006 8:44 am Post subject:

This is a great idea. Give it a go. This analog control is the best way to go for a step sequencer, IMHO. I did this with my sequencer, see: http://electro-music.com/forum/topic-9425.html

This little circuit you found should make this quite easy to build. If you want the conventional single-direction type sequence, just feed it a sawtooth waveform. Very Happy

ian-s · Posted: Fri Mar 24, 2006 3:33 pm Post subject:

Great idea. These type of sequencers are very flexible (they have one on the G2). If you want it to also behave more conventionally (with clock inputs) then you could have a binary divider with R2R DAC as an optional CV.
Having 10 steps is also cool, stick it to the 4/4 guys Very Happy

I guess in it's most basic form it could be considered a CV quantizer.

zipzap · Posted: Sat Mar 25, 2006 9:28 am Post subject:

blue hell · Posted: Sat Mar 25, 2006 9:40 am Post subject:

ian-s · Posted: Sat Mar 25, 2006 11:29 am Post subject:

zipzap · Posted: Sun Mar 26, 2006 10:18 am Post subject:

sorry, i still don´t get it. what does it do? For clocking i thought of an sample and hold, but i guess this is different.

mosc · Posted: Sun Mar 26, 2006 10:42 am Post subject:

This is just a cheap DIY type digital to analog converter circuit.

zipzap · Posted: Sun Mar 26, 2006 11:39 pm Post subject:

converting what from where to whom? (sorry)

ian-s · Posted: Mon Mar 27, 2006 1:13 am Post subject:

Sorry for being so obscure.
If you take an inexpensive 4 bit binary counter chip, stick these resistors on the outputs and you get a clocked staircase voltage generator. Feed this into your voltage in (via a trim pot) and you get a conventional clocked sequencer at very little cost (60cents?). Maybe have a multi input mixer so you can combine various degrees of clocked and random CV's

zipzap · Posted: Mon Mar 27, 2006 1:52 pm Post subject:

now that sounds cool! Mixing those cvs is gona be fun. Just as much fun as using a sample and hold, lfo while modulating lfo speed and shape....
If i get your point all i need is something like a 4017 or 4514 conter ic.
Insted of the r2d2 circuit i could use voltage deviders - an independant sequencer to program (and modulate...) the sequence order.
many possibilities.