# [Video] Tutorial: How to Use AAA Batteries with a Stackmat Instead of 2032s



## ErikJ (Mar 12, 2011)

just a fun little idea I decided to try and it came out excellent.


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## EmersonHerrmann (Mar 12, 2011)

You're a genius


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## masterofthebass (Mar 12, 2011)

Sorry erik, but there is really no point to this. http://cgi.ebay.com/10pc-SONY-CR203...638462971?pt=US_Batteries&hash=item41575b1bfb

$5 for 10. I have 50 cr2032s sitting here that I paid like $10 or $15 for. Don't go to wal-mart or radio shack to get your battery, and everything is fine.


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## ErikJ (Mar 12, 2011)

masterofthebass said:


> Sorry erik, but there is really no point to this. http://cgi.ebay.com/10pc-SONY-CR203...638462971?pt=US_Batteries&hash=item41575b1bfb
> 
> $5 for 10. I have 50 cr2032s sitting here that I paid like $10 or $15 for. Don't go to wal-mart or radio shack to get your battery, and everything is fine.


 
oh well. this only cost me $1.50. I still wonder how much longer AAAs will last.

edit: according to some data I found online the capacity of a CR2032 is about 225 mAh (milli amps x hours) while a AAA is between 1000 mAh and 1200 mAh. so this should last me for a very long time. 

next project: measure the current drawn from the battery while the timer is running to find the total solve time possible.


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## Owen (Mar 12, 2011)

I wonder if a solar cell from a calculator would work. Then it would never run out (unless you're in the dark).


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## timeless (Mar 12, 2011)

or just plug it in to an AC adapter


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## maggot (Mar 12, 2011)

Owen said:


> I wonder if a solar cell from a calculator would work. Then it would never run out (unless you're in the dark).



a green stackmat, how interesting.


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## masterofthebass (Mar 12, 2011)

ErikJ said:


> oh well. this only cost me $1.50. I still wonder how much longer AAAs will last.
> 
> edit: according to some data I found online the capacity of a CR2032 is about 225 mAh (milli amps x hours) while a AAA is between 1000 mAh and 1200 mAh. so this should last me for a very long time.
> 
> next project: measure the current drawn from the battery while the timer is running to find the total solve time possible.


 
I'm surprised that a single AAA works. A CR2032 has a 3V output, while a AAA is only 1.5. O well.


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## FatBoyXPC (Mar 12, 2011)

Dan: Some circuits have a great tolerance for voltage, but take notice how he has two AAA batteries in series. Putting power supplies (in this case: batteries) in series will sum their voltages.

Erik: If you have a DMM you should be able to do your test fairly easily. If I ever change my stackmat to use AAA, I'll do the test for you. Although, if I do that, I don't want a huge battery pack sticking out the front


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## masterofthebass (Mar 12, 2011)

fatboyxpc said:


> Dan: Some circuits have a great tolerance for voltage, but take notice how he has two AAA batteries in series. Putting power supplies (in this case: batteries) in series will sum their voltages.


 
I'm aware of the basic properties of electronic circuits, but I didn't watch the entire video. After the first sentence, it seemed pointless to keep watching.


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## ErikJ (Mar 12, 2011)

masterofthebass said:


> I'm surprised that a single AAA works. A CR2032 has a 3V output, while a AAA is only 1.5. O well.


 
I was using 2 AAAs. did you even watch the video? hahah the data I found was for a single AAA so the overall capacity of my power cell is more than 2000 mAh. which should give me 10 times the battery life than a CR2032. I'd say it's cheaper in the long run.



fatboyxpc said:


> Erik: If you have a DMM you should be able to do your test fairly easily. If I ever change my stackmat to use AAA, I'll do the test for you. Although, if I do that, I don't want a huge battery pack sticking out the front



I have a multimeter. I'm going to measure the voltage output of the CR2032 I just took out of it to find the minimum operating voltage. then I can use equations involving power and energy to calculate the maximum amount of time the timer would run if it could go past 10 minutes. I've taken a bunch of classes involving circuits and I love to do little projects like this so it'll be fun.


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## FatBoyXPC (Mar 12, 2011)

Whenever you hook more than one power supply together (either in parallel or in series), you get a combined effect of voltage or amperage, not both. In your case, series, you got to combine the voltages. Your mAh will stay the same. If you would have hooked the batteries up in parallel, you'd get 1.5 volts but you'd get the amperage combined. Even still, you get nearly ~5x as much time out of 2 AAA's than a single CR2032.

You could just reference the part numbers and rebuild your own. An easy timer circuit you could make is with a 555 chip, a couple resistors, and a couple capacitors.

Since you're already going to play w/all this, why not just go ahead and measure the amperage draw from the battery while using the circuit? The only tricky bit I suppose is keeping some sort of test lead on the CR2032 battery (but taping some bare wire firmly to it should work fine). Don't forget to put the test lead on the DMM onto the fused side (I realize a little CR2032 probably won't blow anything, but you can never be too cautious ).


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## ErikJ (Mar 12, 2011)

fatboyxpc;544270Since you're already going to play w/all this said:


> that's exactly how I was going to do it. it would also be nice to find a way to fit everything inside the stackmat but the space is VERY limited.


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## Radu (Mar 12, 2011)

Instead of letting the users find "solutions" and improve the stackmats, they'd better come up with a new and improved product and not let us use this version which was developed so many years ago.


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## ErikJ (Mar 12, 2011)

pablobaluba said:


> Instead of letting the users find "solutions" and improve the stackmats, they'd better come up with a new and improved product and not let us use this version which was developed so many years ago.


 
the batteries that they use work just fine and they last for quite a while. it's just that I found them to be annoying so I came up with my own solution. 

here are the measurements regarding current I just took:

timer off but date and time are displayed - 4μA (almost nothing)
timer is on and displaying a static time - 0.39mA 
displaying a static time and red LED is on - 2.2mA
displaying a static time and both LEDs are on - 4.8mA
timer is timing - 0.89mA

I guess and easy way to increase battery life would be to unsolder the red LED. this way the green one will still come on to let you know when to start.


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