Simple timed controller

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Discussion Overview

The discussion revolves around designing a circuit to control a relay with a timer using one or two buttons. Participants explore various approaches, including programmable microcontrollers and industrial timers, while considering the functionality and ease of use for specific applications like controlling lights in a shelter.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant describes a desired functionality for a relay control circuit that includes a timer, the ability to extend the timer with multiple button presses, and a reset option.
  • Another participant suggests using a programmable microcontroller, such as an Arduino, as a straightforward solution due to its affordability and availability of tutorials.
  • A different viewpoint emphasizes the potential complexity of building the circuit with dedicated ICs and proposes that a single chip microcontroller on a small PCB could be a simpler alternative.
  • One participant points out the existence of industrial timers that could fulfill the requirements and provides a search link for further exploration.
  • Another participant shares a link to a white paper discussing programmable relay controllers, suggesting that such devices may offer advantages for the proposed application.

Areas of Agreement / Disagreement

Participants express differing opinions on the best approach to achieve the desired functionality, with some advocating for microcontrollers while others suggest looking for existing industrial solutions. No consensus is reached on a single optimal solution.

Contextual Notes

The discussion highlights various assumptions about the complexity of the circuit design and the availability of pre-made solutions, but does not resolve these uncertainties.

solvejskovlund
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I'm looking for a circuit to control a relay using preferably a single button, but two buttons is ok.
I picture a behavior similar to this, starting with the relay control signal off / disconnected / floating:

case 1:
Press the button once: power on the relay, set a timer to X minutes and start count down.
When time runs out, the relay control signal is turned off.

case 2:
Press the button: power on the relay, set timer to X minutes, start count down.
Press the button again: add X minutes to the timer.
For every press on the button another X minutes is added to the timer (guess there should be a max of an hour or two)
When time runs out, the relay control signal is turned off.

Additionally there should be a way to reset timer to 0, power off before the time has run out.

Also I'd like some kind of indicator that indicates the reminding time.

I wouldn't be surprised if a circuit like this exists like a mass produced pcb, or maybe even like a device with a box. But I can't find any. What would be the proper search terms to find such a circuit?
(I've found premade PCBs that has an time setting that can be controlled by multiple buttons, and a main button that starts the timer. But repressing the button either turns off or resets the timer to the initial first press time. They do not extend the time by pressing multiple times.)
The usage of this is lights in a half open shelter. Motion detection lights switch does not work because of animals, and I want this to be controllable with a foot switch cause my hands are usually full when I need to operate this. )
 
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Pretty easy to build using any programmable microcontroller. Start with an Arduino, as it is cheap and probably the easiest due to tons of tutorials.
 
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Sure an arduino would do the job. But if such a circuit is available for order, it may be better/easier. I would assume it exists. I just don't know the correct search term
 
solvejskovlund said:
Sure an arduino would do the job. But if such a circuit is available for order, it may be better/easier. I would assume it exists. I just don't know the correct search term
You will require at least five dedicated ICs to implement the state machine specified in post #1. It will need to employ an up/down counter, and you would need a custom PCB.

It would be much easier to program a single chip microcontroller that comes ready on a small PCB and costs less than$10.

You might consider an analog solution with an op-amp integrator.
 

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