Yes. A return to maximum simplicity. A useful battery removal tool is provided to avoid nail breakages. Also I find AAAs are generally easier to prise out than AAs. 

But if you really need a power switch, just use a pipistrelle. The idea behind these is, hand them out to kids at bat walks, they just work, and you can't accidentally turn them off. 

I LOVE the idea of the mini, the simplicity.  Looks Great. 

AAA bateries is a good idea, the AAAs in the groups Magentas tend to last for 2 or 3 seasons (years) of regular batwalks before they need replacing. So there should be no problem with duration on AAAs

However for the intended use "batwalks" I'd offer a different perspective.  Having run lots of these this year, by far the most stressed time is at the end, getting the kit back in.  

1. Firstly making sure I've got all 25+ detectors back ... not always easy...
2. Then secondly, making sure they were all turned off before they were put back in the box.

Nothing worse than turning up at the next bat walk with flat batteries in a detector as it was left on in the box ...

Thinking back, there is no way I could get batteries out of 25+ detectors, while answering the 101 questions, and also keeping track of kit at the end of a walk.

If there was no switch on the Mini, I'll have to build π•pistrelles for use on batwalks .. which kinda defeats the point of the mini?

As a compromise could there be a switch pad on the mini board, that could be jumpered. or blobbed across if no power switch is required??

Power switch on its way.

UPDATE : done.

Thank you! My batteries rejoice. 

I won't be ordering this version and testing, I've spent way too much on tests this month, so please order some, build them up and let me know how it goes.

Switch version : 

Read "pipistrelle mini - files updated 18th April 2025 - Share Project - PCBWay" on

pipistrelle mini - files updated 18th April 2025 - Share Project - PCBWay

A pipistrelle mini, but with an off switch - take your pick, pop fans

Already had some in the basket, :-) 

Just waiting for PCBway to approve audit.  

Mini cases seem to come out at about $2.91ea + p&p

Yes, this should be an inexpensive build, and as there is no SD card you can happily use inexpensive ceramic capacitors throughout. Mine are still not shipped, PCBWay seem to be having a slow period right now. Hoping to have them in my hands and assembled before 30th, but they'll need to get them on a plane sharpish. 

I do have some AAA battery holders now, and they are TINY compared to the AAs, this will feel surprisingly little in the hand I think. 

If by some chance your PCBs arrive before mine, don't panic if they don't quite work on assembly - this combination of detector only (i.e no recording) and capacitive touch hasn't existed before, so there may be a bot of coding I need to do to get the firmware fully operational on these. So wait for the word and I'll post updated firmware.