Crosstown Traffic: Hackaday features Raspberry Pi-powered foxhunt transmitter — with or without an actual transmitter!
(my apologies about not posting in awhile. I was on jury duty. It was an emotionally draining case. I’ll make up for it over the next few days.)
Hackaday ran an article yesterday that featured a hackaday.io project that Corey KM4EFP posted describing his Raspberry Pi powered Foxhunt transmitter. What I found unique about this is that you can either feed the audio from a Pi output pin directly into a handheld transmitter, or actually transmit RF directly from the output pin (!) by adding a low-pass transmitter. There is far more information about this project available on Corey’s GitHub page. From the Hackaday.io project page:
My foxbox consists of a Raspberry Pi model B with Raspbian running pifox and is powered by a 6000mah usb power bank with a mausberrycircuits.com power switch and my gpio setup is laid out on an electro-resales gpio breakout pcb. All this is fitted inside a 30 caliber ammo can by use of non conductive foam padding. It starts transmitting automatically when the Pi is powered on and the transmit switch is flipped on. The transmission of my call sign and fox message and current time runs through gpio 4 and a lpf before reaching the antenna and also lighting an led indicating a transmission is in progress. No handheld is needed the Pi is the radio transmitter. You can also use audio out on the Pi to trigger vox on a handheld radio if your not comfortable building a low pass filter. Led and switches are also optional as well as automatic or manual transmissions and timing. Build your fox the way that suits you. There are many customizeable settings for pifox to fit your needs
We’ve seen directly driving an antenna from a GPIO pin before using PiFM. I’m not sure I’d use it in any application where I would require frequency stability or any kind of a solid RF signal… but maybe the application of this is better than I originally thought.
(Published from DFW, Texas)