Nuffinga / Babytooth Nano Longrange/Freestyle project

Babytooth class quads (1s, 3" props, pioneered by KababFPV) are amazing freestyle fun. Almost completely silent, small, light and nimble. The Nano Longrange class of quads (1s 3" props, single 18650 battery) are also surprisingly fun - The challenge laying in the build, configuration and pushing as far as you can go on one battery.

And they both run on almost the exact same powertrain - 1202.5 motors in 10-12000kv, 3 inch props and trying to keep things as light as possible. So i set out to build something that can do both. Put in a 450 and rip your local park. Or sling a 18650, add a GPS and see if you can make it to that nearest mountain peak.

The battery holder was designed in partnership with Makesomemore (https://linktr.ee/makesomemore_); well mostly it was me throwing requirements and he did the heavy lifting. I added a couple of tweaks and now we have a battery holder that weighs under a gram, and can securely hold both a 450/550 class battery, and a 18650. For the 18650 i soldered on the battery leads, though i plan to add a magnet based solution soon too.

I have settled on a rear-mounted GPS. Tried mounting it on top of the canopy but seems that the interference from the camera/vtx killed the GPS reception. The result is a 'stringer' that stretches between the rear arms and holds the GPS with the tension of that and the wires going to the FC. Should work with most nano VTX that have a little notch either side of the ceramic antenna. Wont really work for the cycloneRC M1812C since the antenna is flush with the side :(

I am using the Betafpv Matrix 3 in 1 FC (plugs removed) and a Walksnail 1s lite VTX/Camera. The FC can keep the VTX powered up with 5v all the way down to a battery voltage of 2.45v, so you can really push the limits of the 18650 battery. Unfortunately it also powers up the VTX on USB so you might overheat while waiting for GPS. I have an external power supply for the GPS and plug the GPS into that while i wait for the satellites count to go up. Once it hits 15+ sats i swap it over to the FC and power it up... With the new mounting position GPS kept 16-18 sats after taking off!

After a recent panicked search for my downed quad, I decided a buzzer was very necessary. The Matrix doesnt have a buzzer pad, and you should NOT just connect one to the LED pad. It draws more current than that pad can supply and might fry your FC. I created a tiny deadbug circuit on the back of my 9x42mm active buzzer (see last images). Either using an N channel mosfet (AO3400), or an NPN transistor like MMBT3904
https://www.aliexpress.com/item/1005002583539684.html