Another new module in the works. I had a few 74HC595 shift registers in my toolbox and watched some video’s on YT to see what you can do with it. To my surprise i see a lot of LED chasers build with these IC’s but i thought how can i use these IC’s musically and preferably useable in my modular system. So i chained two of them together to test with a few led’s laying around and some buttons for data, clock and latch. I also build a pulse generator using NE555 chip and the clock out to the clock input, leaving the button switch out and guess what, it works. External clock input from my clock generator also works. Great!! Next i tried an output of the shift register, see if i can trigger one of my drum modules and again guess what? It works. So now i basically have an 16 chn gate sequencer with a button to switch bits on high state, and a reset button to clear the shift registers. Everything runs on +5volts. Not sure if i need to use opamps to buffer the outputs of the shift registers and clamping diodes to the clock input for some protection against higher input voltages. Comments on how to improve this idea are very welcome.
I used 4 leds per shift register. Didnt had more in stock
Protection is warranted if it’s working and you don’t want to risk what works.
If you can I’d discover the properties of your edge triggering and as you say you’re outputting a gate why not add a few more identical ic in a gate array, (a gate sequencer driving another and another) then with a bais on the clock signal in each subsequent iteration to drag out the sequences later like a digital effect or an inverse of the initial sequencer state.
I’d also think about performance features like pause/hold or a stutter switch (only name I know for it) a three way ON/OFF/ON switch forcing the sequencer to rush forward or backwards through the sequencer. It’s a very useful engine with so many possibilities.
Yeah great ideas but I need to lookup some schematics to implement. I want to keep it simple. Unlike the CD4017 which is often used to make sequencers, the 74HC595 accepts user button pressed bits to add, like a tap-tempo. the more you tap the button the more bits will be added to the pattern. Thats what’s so nifty about it. the CD4017 just counts up and that’s pretty much it.
I have used the same 74..595s in BEAM robotics for walking insects (a moving sequencer) and that ability to ‘tap in’ bits into a register can be used to generate a nervous net where sensors or switches can allow the robot to navigate, or at least appear to, without any coding.
I recommend taking a look at the whole 74 CMOS range, used in Lunetta modular synthesizers. A DIY rabbit hole if ever there was one. Just be aware that many of these chips have limited protection against over voltage and excessive current (despite the HC in the name) and many projects may require DC coupling or the use of op-amps if you want to merge CMOS modules with eurorack equipment.
Definitely getting close to Turing Machine territory with this idea!
The original Turing machine uses 4000 series logic chips which have the advantage that you can run them at the more usual synthesizer voltages - which is not helpful if you’ve got the 595s to hand of course! I’ve used both in various projects - my ‘ondes Framboise’ digital ondes Martenot emulator uses 74HCT595s (which have the advantage that you can power them from 5V but they will interface to the 3V3 outputs of a Raspberry Pi). I’ll probably stick to CD4015s when I need a shift register for use with the synth though.
I got a few extra of these myself and, apart from driving 7 segment LED displays, I figured out that a typical use in synthesizers is to tap a few of the outputs and feed them back into the input through a couple of XOR gates, in order to get an LFSR, which generates a pseudorandom sequence (essentially a very very long sequence which is perceived as random).
