Pages: [1]   Go Down
Author Topic: Power consumption and battery life question.  (Read 306 times)
0 Members and 1 Guest are viewing this topic.
Offline Offline
Newbie
*
Karma: 0
Posts: 39
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

I am working on an project that requires power for these parts: serial jpg camera, sound sensor, temp sensor, ambient light sensor, barometric sensor, sd card, and WiFi adapter.

All these components are not running at the same time or continuously. Rather like this: camera will take a picture and store it, temp reading and store it, sound reading and store it, light reading and store it, then connect to WiFi and upload to server. This will be done about once a minute.

I would very much like this to be battery operated for flexibility. So my question is how long will something like this last on standard disposable batteries? on rechargeable batteries? Or at the very least give me tips on how to calculate this.

Thank you in advance!

--Mike
Logged

Johannesburg. UTC+2
Offline Offline
Faraday Member
**
Karma: 99
Posts: 4400
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Well I guess the first thing is to find out the current draw under various circumstances, such as "standby" or "taking reading". The maker's sheets might tell you something, or if not you might have to set up a test with an ammeter.

Edit... then something along these lines....

1) Calculate the maximum current required at any moment, to make sure you get a power source capable of that instantaneous supply
2.1) Estimate how long each event takes ... ie how long in seconds is a "take reading", then multiply each of those by each event's current to get a mAseconds estimate for each event. Include the standby as events too remember....
2.2) Add up all the events' mAseconds and get an estimate of the mAhour rating required for battery, bearing in mind what you calculated in (1). (Or divide it into the mAh rating of a known battery and find the hours)
« Last Edit: January 17, 2013, 12:24:34 am by JimboZA » Logged

Roy from ITCrowd: Have you tried turning it off and on again?
I'm on LinkedIn: http://www.linkedin.com/in/jimbrownza

Global Moderator
Boston area, metrowest
Offline Offline
Brattain Member
*****
Karma: 538
Posts: 27114
Author of "Arduino for Teens". Available for Design & Build services. Now with Unlimited Eagle board sizes!
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

Sounds like a couple hundred mA worth of parts. SD card and wifi typically being the big hitters.
Need at least 3 AAs for ~2000-2500mAH.  Maybe get 10-12 hours from it.
Cs, Ds, will give you a lot more.
Logged

Designing & building electrical circuits for over 25 years. Check out the ATMega1284P based Bobuino and other '328P & '1284P creations & offerings at  www.crossroadsfencing.com/BobuinoRev17.
Arduino for Teens available at Amazon.com.

Offline Offline
Newbie
*
Karma: 0
Posts: 39
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Thank you all. That is more or less what I was looking for.
Logged

Cape Town South Africa
Offline Offline
Edison Member
*
Karma: 19
Posts: 1217
A newbie with loads of posts, and still so much to learn !
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

The 7 amphour ( or more ) alarm type batteries are quite cheap if you have the space.
Logged

With my mobile phone I can call people and talk to them -  how smart can you get ?

Offline Offline
Edison Member
*
Karma: 116
Posts: 2205
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Quote
how long will something like this last on standard disposable batteries?

Without actually measuring, it is hard to know.

You should look at those peripherals and think if you can turn them on / off on demand, as a way to reduce power consumption.
Logged

Pages: [1]   Go Up
Jump to: