You might think that there could be no form factor that has not as yet had an Arduino fitted in to it. This morning a new one came our way. [Johan Kanflo]’s AAduino is an Arduino clone with an onboard RF module that fits within the form factor of an AA battery. Putting the Arduino inside its own battery pack makes a very neat and compact self-contained unit.
At the heart of the board is an ATmega328 clocked at 8MHz to reduce power consumption and fused to drop out at 1.7V. The radio module is a HopeRF RFM69C which as supplied is a little bit too big for the AA form factor so [Johan] has carefully filed away the edge of the PCB to make it fit. Enough room is left within the shape of an AA cell for a couple of DS18B20 temperature sensors and an indicator LED. He provides a handy buyer’s guide to the different versions of a 3xAA box with a lid, and all the files associated with the project are available in his GitHub repository.
Especially with the onboard radio module we can see that the AADuino board could be a very useful piece of kit. Perhaps for instance it could be used as a very low power self-contained UKHASnet node.
We’ve featured quite a few Arduino clones over the years that try to break the size mould in some way. This stripboard Arduino almost but not quite equals the AAduino’s size, as does this PCB version barely wider than the DIP package of its processor. But the AADuino is a bit different, in that it’s a ready-made form factor for putting out in the field rather than just another breadboard device. And we like that.
35 thoughts on “The AAduino Is An Arduino In An AA Battery”
I wonder if that antenna is OK being so close to a grounded metallic battery can…
Are these kinds of radio modules really designed to expect a perfectly tuned antenna anyway? Are those little coils of wire perfectly tuned antennas? I would think that even if they were individually adjusted at the factory (which I doubt very much) their tuning would be changed with every bump along the way during shipping and again every time the user touches it during assembly. It probably changes every time a nearby cricket farts!
I would hope that those radios are designed to load up pretty much whatever load they happen to find and the distance specs are underrated enough that you will still get what you paid for despite an unknown antenna efficiency or lack of.
Or are my assumptions wrong?
Well, they are not typically used with well-tuned antennas. But they don’t compensate much for it either. The distance specs are usually hyper-optimistic even for tuned antennas.
Love the sort of idea of a drop-in Arduino. Build a project around the spec for a drop in then you can program it (and program again and again), drop it in…some one get on that.
I was a beer slave for designing a similar project- ESP module on a 18650 footprint. Main intended purpose was that it’s broadcasting RTC 1337 as SSID.
Looks a lot like the JeeNode (http://www.digitalsmarties.net/products/jeenode) with the AA backpack (http://www.digitalsmarties.net/products/aa-power-board). Anyone know the difference?
From the article: “AAduino is an Arduino clone with an onboard RF module that fits within the form factor of an AA battery.”
The second link in your comment shows a AA battery piggybacked on the JeeNode, which is clearly larger than the battery. Since the AAduino is the same size as said battery, it is much smaller than the JeeNode.
Short, but sweet- keep the good articles coming Jenny.
I think it would make a good contest to see what people can fit within the volume of a AA battery.
+1 , True!. I would make an effort on that
Yeah, would be a nice addition to the 1 square inch contest.
+1 . Small form factor, big functionality, let’s bring it on!
I went a bit bigger than an AA by extending outside the enclosure, but I think my AA booster is still pretty practical: https://hackaday.io/project/7050-boostick-small-aa-voltage-booster
How does the RFM69CW compares range-wise to the NRF905 at 433MHz?
I don’t like the NRF905 with all the control pins compared to the NRF24L01, and I can’t really find a module with castellated pins.
So what is it called if an Aardvark swallows it?
Nice! I’d like to see one inside an 18650 cell size, so I can drop it into a USB power bank. If a bit of its own power supply could be squeezed into the cell size too, then even better.
This would be a fantastic device for surveillance or to do a wireless HID attack on a PC. Using an NRF module instead of the hopeRF you could build an implementation of Sammy Kamkar’s keysweeper, and then install the bug into the wireless keyboard’s battery compartment.
Another great use would be to stick it in someone’s wireless mouse with a little photodiode to detect when the LED is on and thus, the mouse is in use, keeping track of when a user is busy using the computer and when they’re not.
i am not sure if you realize this…but once you would put such a module in the battery compartment….the original device does not work anymore.
4 cell battery compartment. Add a two sided PCB to short out the other end of the chain. Boost converter on-board to take the 4.5V up to 6V and the original product still works. Solder some GPIO’s to key points and you’ve converted the device. OK, just as easy to take a small footprint board and shove it inside the case somewhere. But for those projects that absolutely have no case space.
Boost converter on the last stage is brilliant.
For bonus points put it into a battery can, add a cap or lithium cell inside so that it always reads 1.41V or something so that if they pull it and test it really quick it’ll look like it’s a good battery and they’ll replace the rest of them.
well, all my wireless rats have a single AA, take it out, not working anymore.
I fail to see how you could use a product unmodified if you replaced one of the batteries with something electronic or how you can boost back the voltage by being connected in series with the batteries.
if you modify the device, what is the point? you could just power from the original battery.
The wireless keyboard already has a transmitter. Wouldn’t it be easier to eavesdrop on this?
the NSA thanks you for your covert sudgestions. i would love this as a product on hackafruit shops
…FAA bans battery powered devices on planes … :P
The size can be reduced further by using a 14500 battery, and a 2-slot battery holder.
I am sure that if you really want to shrink it, it might fit inside the part of the compartment where there is the switch.
Nice idea. I took a different approach and used a Moteino (from LowPowerLabs), and a 9V battery in a case for holding two 9V batteries. https://piamble.files.wordpress.com/2015/04/moteino-sensor.jpg?w=168&h=300 . I am interested in how long this solution would last (battery-wise). I am getting 9 months, sending a temperature reading every 15 minutes.
I reckon a useful addition to this would be to tag in a boost converter, to compensate for the fact that the arduino’s not a battery; That way, in theory, you could drop it in to any AA battery powered device, and it’d still work OK.
I like the idea, and could be polished a little bit more using an “empty” AA container, something like this http://s.click.aliexpress.com/e/n23RrRZ3F. You can include a miniature cell and put the battery inside a cheap solar garden lights (the ones that works with AA rechargeable battery ) to make an eternal-solar-powered-radio-linked garden lamp!
I love this idea, maybe this is why I bought all those battery springs and plates from mouser. I was wondering why I bought them! lol
I always sigh when I see people using 9V batteries with linear regulators to run a microcontroller that only even needs 2-3V and would be happy with a switched supply. 20% efficiency, that’s good, right? This offers those sorts of people the level of “easy” that they need, and better, they don’t even need a regulator. With this, you even get a standard format inner case!
I think next step develop flexible Arduino power by flexible electronics parts !
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