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delay off timer circuit

Hi, I have a project that I am stuck on and would be really happy if I got a solution. I have two machines that both have footswitch controls with 1/4" jacks. The main unit turns on when the pedal is pressed and off when it's released. The second unit turns on when the pedal is pressed and off when it's pressed a second time. What I want is an adjustable splitter that accepts one footswitch and has leads that plug into both units. I want both units to turn on together and when the pedal is released I want the main unit to stop and the second unit to stop after a time delay (variable from 1-10 seconds). Also, if the pedal is pressed again before the second unit has stopped, I want both units to be on and the second unit's off-delay restarted when the pedal is released. I've played with some 555 timer circuits and relays, but can't figure this out. The voltage on the pedals is low (

Reply to
Lazer
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Reply to
Hal Murray 

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Yup! :-)
Reply to
John Fields

The pedals are just switches. Either pedal works in both units the same. I want them both to turn on when the pedal's pressed. When the pedal's released I want the main unit to go off and the second unit starts a delay for the off.

Reply to
Lazer

+---------------+--[RY2]---+---------+ | | | | | +----||---+---+----g| |s (e) | | | | D2 | | | |> | | | +| \\R1 | [RY1] [D1] [C1] /
Reply to
ehsjr

"Lazer" schreef in bericht news: snipped-for-privacy@42g2000cwt.googlegroups.com...

_________ _________ ____________ FS ____| |____________| |__| |_________ _________ _________ ____________ M1C____| |____________| |__| |_________ _________ _________ ____________ M1on___| |____________| |__| |_________ __ __ __ __ M2C____| |___________| |____| |___________________________| |__ ____ ____ ____ Delay____________| |_________________| |__________| |_____ ______________ ______________________________ M2on___| |_______| |_____

To make things clear I sketched the diagram above. (View with fixed font). So we see the status of FootSwitch, Machine_1_Control, Machine_1_on/off, Machine_2_Control, machine_2_switchoff_Delay and Machine_2_on/off. It will be obvious that Machine_1 simply follows the footswitch and that you will need two timers. One to make the Machine_2_Control pulse the other to make the Delay.

From the diagram you can read that you have to trigger Delay on the trailing (falling) edge of FS. You have to trigger the M2C timer on the leading (rising) edge of FS *unless* Delay is high *and* on the trailing edge of Delay *unless* FS is high. As you have timers already, I give an idea of the logic. The circuit below should work for you.

|| FS----+-----------||-----+----+----+ | || | | | | .-. | | | | | - | | | | ^ | | '-' | | | | | | __ | ----+----+ +---| | __ | |\\ |& |-----|>=| Delay---)---| >O---+---------------------|__| |1 |----M2C_trigger | |/ | +--|__| | | | | | || __ | | +--||---+---+---------| | | | || | | |& |--+ | .-. | ----|__| | | | | | | | | - | | '-' ^ | | | | | | ------+---+ | | |\\ | +---| >O---------------------+ |/ created by Andy´s ASCII-Circuit v1.24.140803 Beta

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You can use NAND gates and use the fourth gate as an extra inverter. 555 timers require negative trigger pulses.

petrus bitbyter

Reply to
petrus bitbyter

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