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Using 2 C005 Timer modules for an on-off timer switch, alternatives for timing, low power?

David0101

May 10, 2020
7
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May 10, 2020
Messages
7
I do a lot of simple blinky projects where I have battery (18650) powered LEDs on for 6 hours and then off for 18. Think solar LED strings, without the solar part, and only recharging about 1x a month.
Since my favorite mc the attiny85 has gotten pretty expensive (or even attiny13), I've looked for alternatives.
This worked on the breadboard- using 2 cheap c005 timer modules, triggering one another for the 'on' / 'off' pattern.
Pretty simple design i think, and cost is good- paid $0.90 for 10 c005, so 9c + about .10 in other components, the vero may be the most expensive part.

Problem is, timing.. These c005 seem pretty bad at timing, as it will change depending on the battery voltage. Boosting or regulating would cause too much battery usage.

Any thoughts on another cheap method to do simple timing, using low power? I'd expect there to be some sort of COB module doing this for things like battery powered outdoor xmas lights, but I haven't found yet.
 

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crutschow

May 7, 2021
839
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839
I have some battery powered LED candles which turn on for about 5-6 hours or so each day and then turn back on in 24 hours.
The on-time starts when you initially turn them on.
Seem to be fairly accurate as I have a half dozen that I turn on at the same time, and they seem to stay in fairly good sync over a several week period (until I have to recharge their batteries).
A chip like they use (I assume it's a chip) might work for you.
 

David0101

May 10, 2020
7
Joined
May 10, 2020
Messages
7
I have some battery powered LED candles which turn on for about 5-6 hours or so each day and then turn back on in 24 hours.
The on-time starts when you initially turn them on.
Seem to be fairly accurate as I have a half dozen that I turn on at the same time, and they seem to stay in fairly good sync over a several week period (until I have to recharge their batteries).
A chip like they use (I assume it's a chip) might work for you.
yep, exactly what I'm looking for- do you know what the chip is in this?
 

TobiH

Dec 7, 2022
3
Joined
Dec 7, 2022
Messages
3
I do a lot of simple blinky projects where I have battery (18650) powered LEDs on for 6 hours and then off for 18. Think solar LED strings, without the solar part, and only recharging about 1x a month.
Since my favorite mc the attiny85 has gotten pretty expensive (or even attiny13), I've looked for alternatives.
This worked on the breadboard- using 2 cheap c005 timer modules, triggering one another for the 'on' / 'off' pattern.
Pretty simple design i think, and cost is good- paid $0.90 for 10 c005, so 9c + about .10 in other components, the vero may be the most expensive part.

Problem is, timing.. These c005 seem pretty bad at timing, as it will change depending on the battery voltage. Boosting or regulating would cause too much battery usage.

Any thoughts on another cheap method to do simple timing, using low power? I'd expect there to be some sort of COB module doing this for things like battery powered outdoor xmas lights, but I haven't found yet.
This is a great idea, I have occasionally been searching the web for years about that. It seems as if all those timed LEDs either have the circuit on board or there is a special COB/IC on some small PCB.
Do you have a simple wiring diagram for your double-c005-on-off-project? I can not figure out things on your breadboard-style-diagram.
You also write that your other projects use attiny85, how do you compensate time-drift? Do you use internal RC or external crystal? Would love to hear about that!
Thanks a lot!
 

dragon

Oct 31, 2022
248
Joined
Oct 31, 2022
Messages
248
why not just use a light sensor and detect the daylight to switch the leds.
 

David0101

May 10, 2020
7
Joined
May 10, 2020
Messages
7
This is a great idea, I have occasionally been searching the web for years about that. It seems as if all those timed LEDs either have the circuit on board or there is a special COB/IC on some small PCB.
Do you have a simple wiring diagram for your double-c005-on-off-project? I can not figure out things on your breadboard-style-diagram.
You also write that your other projects use attiny85, how do you compensate time-drift? Do you use internal RC or external crystal? Would love to hear about that!
Thanks a lot!
I gave up on using the c005 and used another attiny85 from an old project... For the 85's yeah, theres some drift, i add a reset button which I occasionally hit. Its close enough for a couple of weeks, or even until the battery needs recharging.
It would be nice to find a simple IC with a 18off6on, with a crystal...
 

dragon

Oct 31, 2022
248
Joined
Oct 31, 2022
Messages
248
why not use an alarm clock circuit, they should be exact no?
 

dragon

Oct 31, 2022
248
Joined
Oct 31, 2022
Messages
248
Do you have a link to such a circuit? Needs to be low cost and power consumption.
I think these days most people use a microcontroller for them, so maybe just getting an arduino is all you need to do. :)
 

David0101

May 10, 2020
7
Joined
May 10, 2020
Messages
7
Yep, so we are back to the original issue, of trying to find a cheap IC which can replace my attiny85...:D
 

TobiH

Dec 7, 2022
3
Joined
Dec 7, 2022
Messages
3
We are talking about mA of battery drain, so even an attiny running at 1 MHz and something around 3 Volt is draining the battery. All solutions I have found so far are battery-killers in terms of mA, and using some kind of ne555 or other timing IC is way off, too. And, next big issue, we are talking about extremely long timings which no standard (and low-power-operating) IC can do. So, yes, back to the TO question :)
 
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