Auto-reset for 4017

Thread Starter

Ng Yik Hong

Joined Aug 9, 2021
10
Hi folks, I would greatly appreciate and needing some advise on a switching circuit I've gotten from the web. I had assemble the circuit based on the 4017 counter to use as a selector switch and it works fine. However, I would like the selection to goes off(de-selected) after a few seconds automatically, is there a solution where I can add into the circuitry to reset the 4017 chip?

Thanks and best regards,
Joey
 

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dl324

Joined Mar 30, 2015
14,897
Welcome to AAC!

What is the purpose of this circuit? It turns the relays on sequentially until the count gets to the switch, which must be a toggle or slide in your case, that's closed. From the timing components on the oscillator, it will count pretty fast.

A word of advice. Treat schematics that look like they were drawn by a child skeptically. You should also give attribution when you use the work of others.
 

crutschow

Joined Mar 14, 2008
30,431
It would appear you could use the signal at IC1C-1 to provide a MR (master reset) to the CD4017 through a series resistor and a capacitor to ground (increase the 10k resistor to ground at IC2-15 to 1meg).

(I hate schematics where the parts aren't labeled with a reference designation).
 

wayneh

Joined Sep 9, 2010
17,171
I haven't figured out how your circuit functions but one reset method is to use one of the later, currently unused, counter outputs to directly control the reset pin status. You don't need anything except a jumper from the counter to the reset. Perhaps this reset method would be far too fast for your application.
 

panic mode

Joined Oct 10, 2011
2,215
IC1a is a clock oscillator that runs continuously.
rest of IC1 is used as a gate allowing pulses to reach counter 4017. this works when one of selector switches is pressed.
if the output of 4017 is high - nothing happens since pin1 of IC1 is also pulled high by resistor
but if the pressed button is connected to one of outputs that are low, input of IC1c is pulled low (despite pullup resistor) and clock pulses from oscillator can reach the counter and select different output. once the counter reaches correct value that output is high and activates corresponding relay - at the same time clock pulse train is stopped and new relay is activated. once the user releases the button. pullup resistor at pin1 of IC1c maintains high state so circuit remains stable, selected output stays on.

one could remove IC1b and IC1d, and connect output of IC1c directly to IC1a (pin9). the circuit would work (almost) the same way. the difference is that clock would not run all the time, it would only run when needed to change output - but... function would remain the same...

and with the two spare extra gates one can do all kind of magic, including generating positive pulse for master reset after some delay.
 

Thread Starter

Ng Yik Hong

Joined Aug 9, 2021
10
Welcome to AAC!

What is the purpose of this circuit? It turns the relays on sequentially until the count gets to the switch, which must be a toggle or slide in your case, that's closed. From the timing components on the oscillator, it will count pretty fast.

A word of advice. Treat schematics that look like they were drawn by a child skeptically. You should also give attribution when you use the work of others.
I use this circuit as a 1-of-4 quiz selector with 4 momentary switches. This is the 1st time I post on the internet regarding electronics and I apologize for missing out the author.
 

Thread Starter

Ng Yik Hong

Joined Aug 9, 2021
10
It would appear you could use the signal at IC1C-1 to provide a MR (master reset) to the CD4017 through a series resistor and a capacitor to ground (increase the 10k resistor to ground at IC2-15 to 1meg).

(I hate schematics where the parts aren't labeled with a reference designation).
Thank you for the advice. I shall try this out 1st working on the RC discharge timing.

This is the 1st time I post on the internet regarding electronics and I apologize for missing out the author.
I search again on the circuit online and found the author was Jim Rowe from Silicon Chip Electronics
 

Thread Starter

Ng Yik Hong

Joined Aug 9, 2021
10
I haven't figured out how your circuit functions but one reset method is to use one of the later, currently unused, counter outputs to directly control the reset pin status. You don't need anything except a jumper from the counter to the reset. Perhaps this reset method would be far too fast for your application.
Its a 1-of-4 selector switch based on a 4017 counter, upon a switch depressed the counter locked on the last selection. Yes it will be instantly reset the counter if to jumper the output directly to the reset pin.
 

Thread Starter

Ng Yik Hong

Joined Aug 9, 2021
10
IC1a is a clock oscillator that runs continuously.
rest of IC1 is used as a gate allowing pulses to reach counter 4017. this works when one of selector switches is pressed.
if the output of 4017 is high - nothing happens since pin1 of IC1 is also pulled high by resistor
but if the pressed button is connected to one of outputs that are low, input of IC1c is pulled low (despite pullup resistor) and clock pulses from oscillator can reach the counter and select different output. once the counter reaches correct value that output is high and activates corresponding relay - at the same time clock pulse train is stopped and new relay is activated. once the user releases the button. pullup resistor at pin1 of IC1c maintains high state so circuit remains stable, selected output stays on.

one could remove IC1b and IC1d, and connect output of IC1c directly to IC1a (pin9). the circuit would work (almost) the same way. the difference is that clock would not run all the time, it would only run when needed to change output - but... function would remain the same...

and with the two spare extra gates one can do all kind of magic, including generating positive pulse for master reset after some delay.
Thank you for the reply and great information on the removal of the IC1b & IC1d. I am building this circuit for my personal use with no commercial value.. for now I shall work on how to reset the counter after 5~10 seconds.

This is the 1st time I post on the internet regarding electronics and I apologize for missing out the author.
I search again on the circuit online and found the author was Jim Rowe from Silicon Chip Electronics
 

boostbuck

Joined Oct 5, 2017
222
It's a 'radio button' selector circuit using non-latching push-to-make switches. I'm not sure if Jim originated it, but Silicon Chip used it in many of their projects.

The circuit drawing style is out of the magazine from mid 90s onwards. I have some issues with the style myself, but it's a bit cruel to say it looks like it's drawn by a child!
 

panic mode

Joined Oct 10, 2011
2,215
the circuit is well laid out and easy to follow. only resistors and capacitors are without reference labels. some symbols are colored to help avoiding confusion (LED vs signal diode for example). i would not say it was created by children but for children or hobbyists.
 

dl324

Joined Mar 30, 2015
14,897
I use this circuit as a 1-of-4 quiz selector with 4 momentary switches.
Then why not just use a 1 of 4 selector with a timer with a timer to deselect. What happens if more than one switch is selected? What happens if the momentary switch is held down longer than the timeout period?
This is the 1st time I post on the internet regarding electronics and I apologize for missing out the author.
Understandable. You should always give credit if the work isn't yours.
the circuit is well laid out and easy to follow. only resistors and capacitors are without reference labels. some symbols are colored to help avoiding confusion (LED vs signal diode for example).
Humps with connection dots went out around 40 years ago. When color coding is meaningless, it's meaningless. Sometimes pin text is red and sometimes it's black. What's the difference between a switch with a red value instead of green? The flow from the regulator is backwards, unnecessarily. Why do you need to indicated diode polarity when it's already apparent from the symbol? Same for the MOSFET, except that he did include a pinout figure.

EDIT: correct typo.

If he drew it for novices, he's insulting their intelligence. As you pointed out, two of the NAND gates are unnecessary unless the intent is for all count intervals to be the same; but the clock frequency is too fast for that to be relevant.
 
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panic mode

Joined Oct 10, 2011
2,215
I think TS understands that schematics format is not going to win any prize. Perhaps he would prefer tips on modifying circuit over nitpicking on drawing style used by someone else - something he has little control of
 

MisterBill2

Joined Jan 23, 2018
12,690
The Crutschow suggestion in post #3 will work but some experimenting may be required. One very confusing part is the open ends with the -+ after the end. That is not an accepted notation for normal purposes.

If the only purpose is to emulate the "radio button" functionality there are simpler schemes available. It could be done with CMOS 4013 flip-flops, one IC for each two buttons, no limit to how many, and no sequence required. Pressing any button would sens a solid "set" to the selected position and at the same time a short "reset" pulse to all the devices. And it would only require normally open buttons. The button would need to be held pressed for most of a second, though.
 
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Thread Starter

Ng Yik Hong

Joined Aug 9, 2021
10
It would appear you could use the signal at IC1C-1 to provide a MR (master reset) to the CD4017 through a series resistor and a capacitor to ground (increase the 10k resistor to ground at IC2-15 to 1meg).

(I hate schematics where the parts aren't labeled with a reference designation).
220K resistor and a 47uF capacitor but it didn't work, could have I done wrong somewhere?
 

Thread Starter

Ng Yik Hong

Joined Aug 9, 2021
10
Welcome to AAC!

What is the purpose of this circuit? It turns the relays on sequentially until the count gets to the switch, which must be a toggle or slide in your case, that's closed. From the timing components on the oscillator, it will count pretty fast.

A word of advice. Treat schematics that look like they were drawn by a child skeptically. You should also give attribution when you use the work of others.
Buttons are normally open, non latching type. The circuit holds the selection on the last button pressed.
 

dl324

Joined Mar 30, 2015
14,897
Buttons are normally open, non latching type. The circuit holds the selection on the last button pressed.
So, assuming you could press and release a switch before the counter counted to that number, the counter would cycle to 0 and start switching relays again.

What are you switching that you need relays? Does the switching of relays before the switch you press cause a problem? Do you hear them clicking?

It sounds like you just need a 1 of 4 selector. Answer my other questions.
  1. What happens if you press multiple buttons?
  2. What happens if the switch is held down longer than the timeout period?
  3. Do you need the reset switch if you have a timed reset?
 

Thread Starter

Ng Yik Hong

Joined Aug 9, 2021
10
So, assuming you could press and release a switch before the counter counted to that number, the counter would cycle to 0 and start switching relays again.

What are you switching that you need relays? Does the switching of relays before the switch you press cause a problem? Do you hear them clicking?

It sounds like you just need a 1 of 4 selector. Answer my other questions.
  1. What happens if you press multiple buttons?
  2. What happens if the switch is held down longer than the timeout period?
  3. Do you need the reset switch if you have a timed reset?
1 of 4 relays will latched after that button pressed and released, until you select another button. Relay clicks according to the channel button selected. Relay use to power up LED light.

  1. What happens if you press multiple buttons?
Only 1 button will be selected even with multiple button pressed

  1. What happens if the switch is held down longer than the timeout period?
No different

  1. Do you need the reset switch if you have a timed reset?
No reset switch needed but require to have the counter reset, seconds after selected.
 
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