The lowest-cost version of Griff, the wearable USB microphone.

This "Ultimate Economy" version of Griff eliminates the 3D printed mount, and instead mounts a 38mm brooch pin (£4.99 for 50 from Amazon) directly on the back of the circuit board using the hotplate. No hand soldering, no cutting, no hot glueing, just stencil, place components and onto the hotplate. A typical build of a single unit is 10 minutes, dropping to well under 5 minutes per unit if you build more than one. I can make 4 of these in under 10 minutes and I am definitely not the most dextrous person on the planet.

DigiKey shopping list for electronic components : https://www.digikey.co.uk/en/mylists/list/4VEV9FZONF - if you select "2 assemblies" that is enough parts to build 10 Griffs, 1 assembly builds 5, and the 10-off component cost is - on 11th March 2025 - £60.20 + VAT = £72.24, free shipping. Add on 50p for the PCB and you are under £73. Amortizing the shipping and stencil costs over 10 units gets you to around £8.50 per Griff, less if you do subsequent builds so that the stencil cost for additional builds hits zero.

Here is Bat Detector : https://apps.apple.com/gb/app/bat-detector/id6504186190

Here is where I got the 38mm brooch pins : https://www.amazon.co.uk/dp/B0CQH72K3V

It is hard to buy less than 50 an Amazon, maybe your local hobby store (e.g Hobbycraft) will have smaller quantities.

Note that the microphone and the app are ONLY COMPATIBLE WITH iOS. This does not provide a bat detection solution for Android users

UNDER NO CIRCUMSTANCES MAY ANY DEVICES BUILT BE EITHER RESOLD, OR OFFERED FOR SALE. THIS PROJECT IS SUPPLIED ON A STRICTLY NON-COMMERCIAL BASIS. I MAKE NO MONEY FROM THIS PROJECT, AND IN RETURN, BY BUYING PCBS HERE, YOU COMMIT TO MAKE NO MONEY FROM THIS PROJECT. BE NICE, OK?