Thursday, May 30, 2013

Rick Moranis 10 Step Baby Gate Sequencer module based on the CD4017

I Just finished my newest version of the "baby 10 sequencer".  It has control voltage and gate switches.  I found some problems with it, and subsequently this module.  I will be posting some modifications in the next few days. 

In preparation of improving my baby 10 sequencer, I've been coming up with things to do with the CD4017.  A couple weeks ago I built the sub-oscillator out of the CD4017.  That introduced me to the 2 transistor Schmitt Tigger which I borrowed from the Yusynth clock divider.  I also borrowed from that same clock divider, a diode "and" gate which I modified for this project.  I also chose to incorporate a "gate to trigger" circuit similar to Ken Stones Gate to tigger circuit for my reset sync input.  I'm not sure how much of this module you could actually call mine, but I guess this is how you learn at first.  Working out this circuit will be a big help when I move onto my all encompassing 10 step baby sequencer.  possibly my next project.

I did a mock up on a breadboard of my idea to make sure they would work.  here is a video.

then I drew up a schematic incorporating all these different ideas

I came up with a cool idea too as I was trying to do the panel layout.  I hate rotary switches!  they are expensive and I find them to be panal hogs.  There just wasn't enough room to incorporate all the inputs, outputs, switches and LEDs I wanted in a single module width while still having that clunky 10 position rotary switch.  So I came up with an idea of using a SPDT(on/off/on) switch to control the gate as well as the reset.  the positions work like this (gate one/gate off/ Reset).  One thing to be noted is that having more than a single switch in the reset position will cancel the reset out.  This could be fixed by adding diodes but I felt that would be mostly unnecessary and would add 10 diodes the PCB, when really, all you have to do is not have 2 switches set to reset at the same time (something you don't have to worry about with a rotary switch)

I'm also proud to say that this single sided PCB layout has no jumper wires!


1 X CD4017
1 X TL072
1 X 741
4 X NPN transistors ( I used 3904s)
7 X Diodes 914s or 4148s

10 X SPDT (on/off/on) mini toggle switches
11 X LED's 
4 X 1/4" jacks

1 X .0015uf cap
2 X 22uf Cap 

12 X 2k4 Ω 
3 X 1k Ω
1 X 15k Ω
3 X 22k Ω
1 X 220 Ω 100Ω
1 X 47k Ω
8 X 100k Ω
2 X 10 Ω
1 X 4k7 Ω

I guess they only thing I really have to clarify is how the switches and LEDs are wired.  The "switch&led sends" should be connected to the center of the SPDT switch. the Positive leg (longer leg) of the led should be connect to the bottom switch lug (so when the switch is in the up position, it connects the LED and switch send) and the top switch lug should be connected to the "reset return".  I panel wired all the reset turn lugs together.  The negative side of the LED should be connected to the "switch&led returns" bank.  Then of course the labeled outs and ins should go to their designated 1/4" jacks.  The last LED is the final gate LED which is labeled on the top centerish of the PCB.  that should be connected to the positive side of the LED and the negative side to ground.

I did this kinda fun .gif of me designing the PCB.  I changed a couple things from this version to the final PCB layout which you might notice if you look carefully. 

These PCBs are ready to etch, print them and transfer them.
I noticed that an extra hole ended up on the PCB just below the right side of the diode on the left bottom, ignore it. 
For the panel layout, I went with Rick Moranis because I'd just watched Ghostbusters. if you want to etch this, you should flip in horizontally and invert it in photoshop. 

And last, a video.  ENJOY!

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