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Suggetions for up counter/relay driver?

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eTech

Well-Known Member
Hi

I'm looking for suggestions on an digital up counter that would sequencially drive 4 outputs
each connecting to a relay.

1. Input would be a momemtary pushbutton.
2. Relay 1 would be energized, by default, after power up.
3. Each time the button is pressed, it would energized the next relay in sequencial order.
4. If the PB is pressed after the 4 relay is energized, I want the count to reset and
start with 1 energized again.
5. Each relay would latch until reset ( see #4 above)
6. 12vdc supply is preferred.
7. II'll be using a 4011 circuit to drive a 2 digit 7 segment LED Display and indicate a value
represented by a combination of the relays energized. For example:
If relay 1 = 2 and relay 2 = 4 then if both relays energized, display "6" on LED display.

Thanks!
 
hi,
I would use a 4bit shift register to clock in a high state on each press, use a transistor driver on each output pin of the S/R to drive a relay and a single LED for each output.

Your display idea seems a little too complicated to see the state of 4 relays.
 
If the relays represent 2,4,8,16 and are activated as described then the count will go 2,6,14,30. Is that what you want?
 
If the relays represent 2,4,8,16 and are activated as described then the count will go 2,6,14,30. Is that what you want?

Hi
What I really want is the relays to energize and latch one at a time, in sequence, with each press of the button. Then reset if the button is pressed and all four relays are energized.

Thanks
 
There should be a way to do this using a 4017 with a few 4013 D flip flops. The 4017 Q1, Q2, Q3 and Q4 would drive the 4013 clock inputs and each 4013 would sequentially latch. Then the 4017 Q5 would be a reset. Each button press would clock the 4017 sequentially turning on the next relay (4 button pushes N/O push button) at that point all 4 relays are on and on the 5th button press the 4017 resets and all 4 relays turn off and Q5 resets the pair of 4013s? Maybe something like that? I am tired and maybe tomorrow I can think about it. Eric & Alec, do you think that would work?

Ron
 
Hi
What I really want is the relays to energize and latch one at a time, in sequence, with each press of the button. Then reset if the button is pressed and all four relays are energized.

Thanks

hi,
I would consider an option as shown in this image.
 
Didn't the OP want Relay1 to activate at power up?
 
According to the OP's spec Relay1 is on all the time (apart from prior to power-up), so perhaps is redundant?
 
According to the OP's spec Relay1 is on all the time (apart from prior to power-up), so perhaps is redundant?

That is correct, I have just made it a part of the S/R outputs to keep the design flexible, you know how these OP specifications can change after a few posts.

E
 
Yes; only too well :)
 
hi,
I would consider an option as shown in this image.

Hi Eric

Thanks for your input...

This looks good...but I need the relays to be controlled from the +12 side. :-|

I know.....I should of put that in the spec... :)

Anyway...
I can modify the relay drive circuit to use a PNP driver (2N2907) , but if I do, I'll need to change the control output from the 74164 to be high and go low to energize the relay.
Is there an easy way to make this change? a 74164 chip replacement perhaps?

Suggestions?

Thanks
 
Last edited:
I went ahead and modified the circuit.
Please review...

This section of the circuit will not work, the transistor will never switch off also the 74HCT04 will have 12V on its output if it did.

Why do you want to use PNP rather than NPN.???
 
This section of the circuit will not work, the transistor will never switch off also the 74HCT04 will have 12V on its output if it did.

Why do you want to use PNP rather than NPN.???

your right...it won't work.

I want to keep all the controll switching done from the positive side of the source and negative side connected at ground potential.
I have other circuits in my project that will also be switched from the positive side.

I think what I need to do is modify your original NPN driver and connect it to a PNP stage that drives the relay...

Thanks fro your help...
 
your right...it won't work.

I want to keep all the controll switching done from the positive side of the source and negative side connected at ground potential.
I have other circuits in my project that will also be switched from the positive side.

I think what I need to do is modify your original NPN driver and connect it to a PNP stage that drives the relay...

Thanks fro your help...

hi,
If you want a IC solution rather than NPN driver, look at the 74LS06 open collector [30V out range] inverters.

For reference the 74LS07 is a non inverting o/c output buffer
 
Last edited:
Hi all.

Decided to go with the NPN/PNP driver...:)

Have a look...

Thanks everyone

Thanks Eric..

:)
 
Hi all.

Decided to go with the NPN/PNP driver...:)

Have a look...

Thanks everyone

Thanks Eric..

:)

hi eT,
I have changed the values of the resistors in the NPN driver stage, your collector current was excessive and wasteful, also changed your 'exotic' resistor values to preferred values.

Modified as file attached.

E.
 
hi eT,
I have changed the values of the resistors in the NPN driver stage, your collector current was excessive and wasteful, also changed your 'exotic' resistor values to preferred values.

Modified as file attached.

E.

Hi E

Please clairify?

thanks
 
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