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anclib
Joined: Oct 12, 2012 Posts: 12 Location: UK
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Posted: Tue Apr 01, 2014 10:31 am Post subject:
cd4066b bi lateral switch problem |
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Hello, please help.
I currently am having problems getting my project working which is a drum sequencer.
I have a wav trigger board, which has 16 inputs to trigger wav sounds, I have a matrix of push latch switches on a board and a CD4015 creating the sequence.
On each step I have taken an output from the CD4015 and fed it to the corresponding row of switches, then this feeds to a CD4066 to drive the wave trigger board input switch.
My problem is that the CD4066's seem to be turning on and off at random, but when I ground out the earth supply to the cd4066's with my hand it seems to work better, but not 100%.
A few possible things I think could be causing this are:
1. not enough voltage going to the switch board and feeding through to the 4066's
2. some sort of ground problem or back voltage problem
3. noise in the inputs to the 4066s
I just thought I would ask the community before digging in headlong.
I have a load of lm324s so I was thinking maybe boosting the input signals coming from the switch board.
Any help is very much appreciated. |
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PHOBoS
Joined: Jan 14, 2010 Posts: 5591 Location: Moon Base
Audio files: 705
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Posted: Tue Apr 01, 2014 12:24 pm Post subject:
Re: cd4066b bi lateral switch problem |
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hmm a schematic would be very useful here.
Quote: | I have a wav trigger board, which has 16 inputs to trigger wav sounds |
What kind of inputs are they. Do they need a trigger voltage or is it like a switch contact you could connect something like a pedal to ?
Did you connect the control inputs of the 4066 directly to the 4015 or do you have the switches in between ? If so did you use any pulldown
resistors or do they float when the switch is open ?. Do you have any (other) inputs floating ? _________________ "My perf, it's full of holes!"
http://phobos.000space.com/
SoundCloud BandCamp MixCloud Stickney Synthyards Captain Collider Twitch YouTube |
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anclib
Joined: Oct 12, 2012 Posts: 12 Location: UK
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PHOBoS
Joined: Jan 14, 2010 Posts: 5591 Location: Moon Base
Audio files: 705
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Posted: Tue Apr 01, 2014 6:27 pm Post subject:
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Adding some pulldown resistors to the control inputs of the 4066 will most likely solve your problem. If the inputs are left floating the state is
undetermined. And the inputs are very sensitive to noise especially with the wires acting as antenna's. This can actually be fun to play with like a sort of
theremin but probably not what you want right now
nice wavplayer btw _________________ "My perf, it's full of holes!"
http://phobos.000space.com/
SoundCloud BandCamp MixCloud Stickney Synthyards Captain Collider Twitch YouTube |
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bod
Joined: Apr 28, 2009 Posts: 148 Location: Glasgow
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Posted: Wed Apr 02, 2014 4:24 am Post subject:
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yeah, id go for pull down resistors on the inputs of any cmos based IC's as standard which will probably solve your problem here too |
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anclib
Joined: Oct 12, 2012 Posts: 12 Location: UK
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Posted: Wed Apr 02, 2014 6:22 am Post subject:
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Hi thanks for your help.
any idea of the pull down resistor value? hi/low? or will anything do? |
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bubzy
Joined: Oct 27, 2010 Posts: 594 Location: United Kingdom
Audio files: 64
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Posted: Wed Apr 02, 2014 7:24 am Post subject:
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i use 100k for pullup/downs _________________ _Richard_ |
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PHOBoS
Joined: Jan 14, 2010 Posts: 5591 Location: Moon Base
Audio files: 705
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