Turn on Arduino at intervals

I have an Arduino used as a data logger that radios data at hourly intervals.

The trouble is the power draw between samples. What I need is a low power consumption timer circuit that can wake the Arduino up every x minutes (programmable) and then switch it off after it transmits a reading.

I'm sure it could be done with a 555 timer or similar, but I'm not a electronics person so would appreciate some help.

thanks in advance

steveh

why don't you get a christmas tree lights timer. Most of the new ones allow you to set the intervals. The electronic circuit you need
is a two stage 555 long duration astable that has a first stage with a pot adjustable time duration. It goes high for x minutes or hours and then low for the same time period.(50% duty cycle) the second stage is a short duration timer 2 minutes or so, also adjustable to 10 min . When it comes on, it turns on the power for the arduino, which automatically runs the current sketch (to transmit reading) and when the power goes off the cycle is complete and repeats again in x min or hours. The second stage is a
Monostable , or ONE-SHOT (One pulse) whereas the first stage is astable , continuously alternating on/off.

A Christmas tree light timer sounds fine as long as its battery powered as I don't have mains at the Arduino.

You can use the watchDog it has a maximum wakeup interval of 8seconds and then again it goes off and again wakeup after this time! this will help a lot of battery savings.

If you're using any of the official Arduinos or the common clones with linear voltage regulators then sleeping the Arduino will not reduce the power consumption much, because the rest of the board continues to draw power even when the microcontroller is sleeping. In order to minimise power consumption for battery use you need to eliminate all the ancilliary devices and use a minimal Arduino - either a standalone chip, or a clone which is designed for minimal power consumption.

The low power consumption options using any of the official Arduinos all involve powering the whole unit off and using an external timer circuit to power it back on as required. That seems like a more expensive, more complicated and more difficult solution but it's technically feasible if you are committed to using an official Arduino.

"The low power consumption options using any of the official Arduinos all involve powering the whole unit off and using an external timer circuit to power it back on as required. That seems like a more expensive, more complicated and more difficult solution but it's technically feasible if you are committed to using an official Arduino."

That's what I had in mind, I use a Freetronics Eleven board and don't want to go to the trouble of stripping it down.

That's what I had in mind, I use a Freetronics Eleven board and don't want to go to the trouble of stripping it down.

Not stripping it down but perhaps removing some uneccessary stuff of the board if the circuitry allows as such. removing voltage regulators and running on a low clock(and sleeping in between) can be a very good alternative but only if circuitry alllows so goto schematics for your board