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A timer device with relay

I've been looking for a low power and low cost timer device or info on how I could use to build one. I need to turn a relay on on a 5V device (a weather meter doing a number of other task as well). The weather meter uses too much amps for it to run on a battery. The low poer timer device would run on coin cell batteries and very hour or another predetermined time turn on a relay which would then turn power on the weather meter (it uses a 9V battery). I've gotten a number of links to aruduino like systems but these use too much current.

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Test
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A number of Intermatic timers run on a battery, but control a relay that can be controlling any voltage up to 220VAC. ...Jim Thompson

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| James E.Thompson                                 |    mens     | 
| Analog Innovations                               |     et      | 
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Reply to
Jim Thompson

What's low power? AC, DC what voltage? Something like an AC synchronous clock motor and gear head that spins once an hour?

George H.

Reply to
George Herold

A simple 55IC timer will do you. Google on 555 timer circuit. It's simple IC plus a few resistors and caps. The 555 output will need to drive a transistor base thru a ~5K resistor to pull in the relay between the collector and power supply.

Reply to
sdeyoreo

Does it need absolute accuracy (a specific time of day) or relative accuracy (every X hours +/- x minutes)?

Picaxe is easy to use and can be happy on a few micro amps. 555 (cmos version) ditto. Picaxe can be set from milliseconds to decades without large timing caps.

I'm doing stuff with small solar cells and capacitors for power storage.

Reply to
default

If the arduino's using too much current you're doing it wrong.

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Reply to
Jasen Betts

The old favorite ne555 will be suggested by many, but it does draw 1 - 5 mA while doing nothing. Much lower power use can be obtained from something like a Texas Instruments MSP430 MCU running Mecrisp Forth in low power mode 3

The Ti datasheet indicates that a maximum quiescent current draw of 1.5 uA applies in LPM3 (low power mode 3) with a 32768 Hz clock.

Of course the MSP430 MCU can be used for a lot more than crystal controlled timing delays at the price of more power usage.

Cheers, Terry

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Reply to
Terry Porter

You can use a RTC, like:

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and program it to set the Square Wave Output every hour.

Bye Jack

Reply to
jack4747

Vampire voltage?

Reply to
bruce2bowser

the internal voltage divider

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Reply to
Jasen Betts

Test wrote on 10/25/2017 9:00 AM:

Is this what you are looking for?

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Rick C 

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Reply to
rickman

rickman wrote on 10/27/2017 7:12 PM:

If 15 mA is too much current, you can use this with a low power MCU board.

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Here is a low power MCU board.

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Rick C 

Viewed the eclipse at Wintercrest Farms, 
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Reply to
rickman

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