http://luckylarry.co.uk/arduino-projects/making-a-9v-battery-dc-power-supply/ Fri, 11 May 2012 23:24:03 +0000 hourly 1 http://wordpress.org/?v=213 http://luckylarry.co.uk/arduino-projects/making-a-9v-battery-dc-power-supply/comment-page-1/#comment-1159 larry Sun, 27 Dec 2009 14:15:38 +0000 http://luckylarry.co.uk/?p=89#comment-1159 Well I've not changed my battery since I made this and its powered the Arduino board for a long time! I guess you're going to be using the Arduino to control the piezo speaker? the average 9v battery will have about 300mAh when fully charged. Each of the Arduino pins use up to 40mA and then you've got to factor in your code running - how much its using the chip, sending instructions etc... if the piezo is playing constantly and so on. So you should get maybe 2-3 hours if its running constantly I reckon maybe more depending on what you do. If you want it running for much longer than ge some AA batterys and solder a battery pack as you'll be able to get 2-3000 mAh, then your Arduino will run for days. There's some interesting work here similar to this topic at: <a href="http://interface.khm.de/index.php/lab/experiments/sleep_watchdog_battery/" rel="nofollow">http://interface.khm.de/index.php/lab/experiments/sleep_watchdog_battery/</a> Well I’ve not changed my battery since I made this and its powered the Arduino board for a long time! I guess you’re going to be using the Arduino to control the piezo speaker? the average 9v battery will have about 300mAh when fully charged. Each of the Arduino pins use up to 40mA and then you’ve got to factor in your code running – how much its using the chip, sending instructions etc… if the piezo is playing constantly and so on. So you should get maybe 2-3 hours if its running constantly I reckon maybe more depending on what you do. If you want it running for much longer than ge some AA batterys and solder a battery pack as you’ll be able to get 2-3000 mAh, then your Arduino will run for days. There’s some interesting work here similar to this topic at: http://interface.khm.de/index.php/lab/experiments/sleep_watchdog_battery/

]]> http://luckylarry.co.uk/arduino-projects/making-a-9v-battery-dc-power-supply/comment-page-1/#comment-1157 bluebo Sun, 27 Dec 2009 07:04:52 +0000 http://luckylarry.co.uk/?p=89#comment-1157 How long do you think the battery will last having a piezo playing a tune? How long do you think the battery will last having a piezo playing a tune?

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