Let's Make Robots!

Low Battery Notice


Ever wanted to know if your battery has just the right voltage to run your robot. Sometimes I stick a battery in a robot and it just limps over. I figures that the voltage triger from solarbotics could do the job.

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Sorry for this noobish question. I just want to get this striaght. Does the voltage trigger activates when the voltage that enters it is greater or equal to its preset voltage requirement? Or is it something different?

I found this in the picaxe manual 2 and I found it works well.

calibadc b1

b0=255*6/b1

The calibadc command reads the value you would get if you were to read an analog input at 0.6V. the second line recalculates the present voltage for the picaxe (times 10). So if you feed the picaxe 4.8V -> b0 will have a value of 48. 

Off course: if you use a voltregulator (like me) you will allways get a steady 5.2V until the battery output is so low that the voltreg doesn't do anything and the voltage to the picaxe drops below 5V.

If you run your picaxe directly from the battery these commands should work well. 

I really like the concept. If your bot needs 4.6V min, you could use a U-type attached to an LED which would go out when your Vbat dropped below 4.6V. Or use it as an input to your MCU to cause a light to flash at the danger level.

This would be no good as a standalone battery checker, though. Certainly, it could be used standalone battery voltage checker, but that information might not ba any use to you. This device only draws 1uA at 5V, so it won't tell you what your battery voltage will be once you attach a 500mA robot to it. You'd need to build it into each robot.

My personal solution is to use an ADC input to my pic to constantly measure the battery voltage. Of course you need a voltage reference - select an MCU with an inbuilt one.

...or read up on brownout detection...

Yeah I know. I just got the picture by looking on google. It wasn't going to be a stand alone Battery voltage checker. It was ment to be on a robot.
I know you know, though it's hard to know who knows what, you know. :-)
Oh great!  I was looking for this IC, not for testing batteries but to make a BEAMbot with a solar engine, it's funny.