4017 basic 8 sequencer with CV in  - Page 1
Forum section: electronics / beginners

author: omatsynapsys
author_rank: Newbie
timestamp: January 07, 2019, 08:58:33 pm
content: hi there everyone im new to this site ..and quite also on music electronicsi recently builded some 555 oscilators and long ago some attari punks ...i ve been wanting to complete at least a 8 step sequencer using 2 555 and 1 4017 chips .1 555 as a clock wich seems to not have so much range in terms of speed,,and another as a oscilator sourceive managed to make the steps run , 1 - 8 and reset ... but i just dont know how to addeach step a potenciometer and make it sound ... dunno where the sound most come from and where to goive done many tests of course coming from pin 3/1/7 out of the 555 oscilator into each of the outputs of the 4017and many other ways but nothing seem to work or make sound jall i get is the normal sound coming from the 555 oscilator with a slight velocity on the back coming from the 4017:S2.0= question where would the CV in go ... ?thanks a lot if someone answers would beeee such a help

author: Buriedcode
author_rank: Super Contributor
timestamp: January 07, 2019, 09:29:48 pm
content: It is somewhat difficult to understand what you want to do, and what difficulties you're having. SO I don't know how to start to helpBUT... you can use google translate or try and thing of a very simple way of explaining what you want to achieve. A 555 timer is a common device that most here will be familiar with, same with the 4017 (making light chasers etc..). The 555 can make "sound" but only a simple square-wave, and for driving running lights (the 4017) it is often run at a very low frequency, < 10Hz, where-as for sounds obviousl 100 - 3kHz is the usual range.If I understand you correctly you wish to make a music sequencer - with 8 steps - where each step makes a sound, like a drum sound or changes the pitch/frequency of an oscillator. For this you would need a circuit to actually make the sound when triggered by an input. You can use 8 of these, for triggering different sounds, or one, combined with potentiometers and diodes to change the pitch of an oscillator."CV" I assume is the control voltage, used to determine the frequency of an oscillator? or something else? It is also a pin on the 555 used to pull the frequency of the 555 of its centre frequency - usually increasing it.If I am correct here, I would start with making a single "module" that makes a sound when its input is made high. Often these can be as simple as two 555's (or an NE556).I think this is what you're talking about:https://hackaday.com/2016/01/14/oh-baby-baby10-build-a-classic-analog-music-sequencer/

author: L_Euler
author_rank: Regular Contributor
timestamp: January 09, 2019, 12:42:45 am
content: You will need to feed each 4017 output to a potentiometer and then selectively apply the potentiometer outputs to the CV out port by either a multiplexer or steering diodes. Note that you will drop about .7V across the steering diodes. The CV can be tuned with each Potentiometer and used as the control voltage to your Voltage controlled oscillator (VCO). Based on what I am able to understand from your post, you will need a VCO to generate a tone from your sequencer CV out. A sequencer on its own does not generate a sound. Attached is a 16 channel sequencer I am in the process of building using a couple 16 channel multiplexers and a Teensy micro controller.