Arduino Sketch (from Google Drive) Arduino Sketch V2 (from Google Drive) Arduino Sketch V3 (from Google Drive) V2 is a little easier to read, and I changed the functions. V3 is just a different animal to see if I could write the program to use less space. It is not easy to modify AT ALL! Have fun with them.
This won’t be one of those long winded posts. I hope that the picture is worth more than a thousand words. I’ve wanted to make an Arduino controlled fox transmitter for Amateur Radio Direction Finding (ARDF) that didn’t take an engineering degree to make. Yeah, the programming might have been a bit, but I’ve commented it enough that it shouldn’t be too difficult to see what is happening.
If you don’t already have it, download the Arduino IDE from arduino.cc and get a copy of my code from the top of this post. At minimum change the call sign in the Arduino sketch to your call then download it to the Arduino. Make the circuit as shown in the diagram. That’s really all.
3D print and a $3 buck converter! While I was printing 18650 battery cases for my Baofeng and my Yaesu HTs, I was wondering what would happen if I built a regulated linear power for my Baofeng so I could run it from 12 volts. (You can buy a battery eliminator for about $14, but you’ll still have to cut the cigarette lighter adapter off to use with some other connector.) Back to the DIY…I did some rough math in my head and decided that a linear supply would be a waste of energy in heat that I didn’t want. PLA melts at a low temperature AND I was wanting to use the radio in a battery powered ARDF fox box so power consumption conservation is paramount! I decided I’d look at building a switching DC-DC buck converter which is about 100% more efficient compared to a linear supply (about 90% efficient overall).
After looking at the easy schematic, I quickly realized I could probably get one cheaper than the sum of the parts and shipping. Off to eBay I went. I was not disappointed. You can either buy them in bulk from China for about $5 or you can buy one from a guy in Georgia for $2.75. I’ve included the edited screen shot from eBay. Shipping is fast, and I am very pleased. I’ve bought two from the seller because I reversed the leads on the first one and burned it up. Hint: WATCH YOUR POLARITY! These are not forgiving.
All I had to do then was connect the wires! I chose to use a barrel connector on the back because of the power splitter I’m using in the fox box. I’m usually a fan of Anderson Powerpole connectors, but this time around I chose something different. The input and output polarities are clearly labeled on the circuit board. You need almost no electronics knowledge to make this work! Just watch your polarities.
Finally, you hook it up to a 12v supply and turn the little potentiometer until the voltage is where you want it. I chose 7.4 volts which is the nominal Li-ion battery voltage.