Tag Archives: 3D printer

Elecraft KX2 Serial Remote Control using an Arduino Nano – DIY Programming Project with Electronics

Temporary link to video (unreleased) https://youtu.be/SxZHe3Q8yS0

Source Code (Arduino Sketch) – https://drive.google.com/file/d/1vAFgU1TkJCllOeE5bnVJjdRnTjgfB0MQ/view?usp=sharing

Video Script:
Demonstration of what I’ve made! While the KX2 has all of the functions built in, I wanted a way to quickly make changes without having to dig through menus and button combinations. The major reason that I wanted to make a control box is for sending pre-recorded messages in CW and SSB modes. Almost every time I pushed the MSG button I would inadvertently tap the VFO and change my transmit frequency. Then I found some other settings that I would like to have one button push to activate. A couple of settings could take several minutes to set up if they get out of whack, and they can be done in less than a second with the simple push of a button.

For CW, switches 1 through 3 send a pre-recorded CW message. Switch 5 changes the filter settings to a weak signal setting.

The SSB mode has two pre-recorded message switches and settings to reset the AF GAIN, MIC GAIN, and COMPRESSION levels.

The data setting changes a ton of things so you can hook the KX2 to a PC for digital modes. It would take quite some time to make those changes, and this macro sets it up in a matter of seconds.

Finally, all settings have an RF GAIN reduction macro to reduce the gain in the presence of strong signals. As programmed it will reduce the AF GAIN by -3, -5, -10, -20, and -60dB without needing to use the settings menu.

The Anderson Powerpole connectors allow you to use a power supply to power both the Arduino Nano and the radio, if needed.

Construction Segment – The Nuts and Bolts
Shown here is my prototype that I built on a breadboard with the Arduino Uno. Prior to this point I gathered the following materials for my build. If you build the exact model that I did, you’ll need:
1 – Arduino Nano
5 – single pole single throw momentary switches
1 – 3.5mm TRS (stereo) jack
2 – 15A Anderson Powerpoles
About a dozen jumper wires in assorted colors plus two 10AWG wires to loop power from one Powerpole to the other.
I used Q Dope as a temporary adhesive to hold a few things in place
I 3D printed a dual Anderson mount found at Thingiverse
https://www.thingiverse.com/thing:1205771 Anderson PowerPole “Wall” Mounts by VCHSRobotics December 16, 2015
You’ll need an enclosure. I used a box that my guitar pickup was shipped in. 3D printing an enclosure would have been my choice, but I found this while looking for parts, and I liked it!
I gathered some of the parts to do a dry fit on the enclosure to make sure everything could be crammed in there.
I cut the end of the enclosure to install the Powerpoles and power for the Arduino board.
Next I used Scotch tape, a permanent marker, and a pair of calipers to score where I wanted the switch holes to be.
Carefully, I drilled each hole to the size of the panel mount switches.
I used jumper wires with one end cut off to connect the switches to the Arduino Nano. I soldered the power and ground directly to the board. I also soldered three jumpers to the TRS jack for the serial communications to the KX2.
The next step was to program the Arduino Nano and test functionality before “gluing” the jumper wires and placing the Arduino board into the enclosure.
Everything is closed up so alpha testing can commence.
I printed a label, albeit incorrect and not final, to adhere to the front of the remote control box. Buttons 4 and 5 are swapped, and I added more functions after I tested the system live in the field during a #POTA activation.
This image is me alpha testing my design in real time during a real #POTA activation at K-2195 Reed Bingham State Park. I discovered that there were some timing issues that I needed to correct in the software, and I made a list of additional functions that I wanted to add.

Files hosted at http://w1rcp.com

#elecraft #kx2 #pota #arduino #hamradio #amateur #radio #diy #electronics #parks on the #air

Baofeng Battery Eliminator

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.

The first step was to print the modified battery case. I used Tinfoil_Haberdashery’s original Baofeng 18650 case, but I used Tinkercad to cut out the middle so the buck converter could fit in it, and I added a hole in the back for the wires. (Here’s my STL file.)

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.



Yaesu FT-60R 18650 Battery Compartment 3D Print

18650 Battery Box for my Yaesu FT-60

I printed someone else’s 18650 battery box for my Baofeng the other day, and it worked so well that I wanted the same thing for my Yaesu FT-60. I searched the web for a while, and I couldn’t find where anyone had actually printed a battery box for it. I found where they hacked up $25 AA battery boxes for the radio; I don’t want to hack that up. 🙂 For the cost of some Altoid tin steel and a little PLA plastic I was able to make a sweet battery box for my Yaesu FT-60R.

Check out Thingiverse for my post and the STL files.

Raspberry Pi Controlled Amateur Radio Fox Transmitter

My friend KT created a cool looking vinyl fox for the outside of my fox box. The rubber ducky connects to an SMA bulkhead. The screws hold the Raspberry Pi and the interface box inside.

The radio is hanging on a 3D printed bracket, the Raspi is in an enclosure that I found on Thingiverse, and below the Pi is a 3D printed controller box.

Lately I have been reading about Amateur Radio fox hunting, and I wanted to make my very own fox. I saw some cool transmitters that are very small, and I have seen transmitters in ammo cans, and I really like the look of the ones in the ammo cans. I also set out to spend as little money as possible, so buying a small transmitter (around $100), was out of the question. I needed to use as much as I had at home.

The first thing to do was to acquire an ammo can from the Army Navy Surplus Store. This set me back $10 cash. I had some at home, but I didn’t want to empty them. Now, it’s time to get to the fun part.

Schematic and wiring diagram.

Some people used Arduino microcontrollers to do the PTT and audio. I have an Arduino, but I really didn’t want to be limited to the audio created by software; I wanted to be able to use actual audio files right out of the box. This was what drove me to use a Raspberry Pi. Someone else used a Model B Pi as a transmitter. I didn’t want to go that route, but it looks really cool, and it was really small! I have more of the first rev B models than I do Arduinos anyways, and I’m always wondering what I could do with them since they pale in comparison to their newer model 3! The trade off is power consumption. The model B Raspi uses about 400mA. Using a newer model would improve this, but I’m using what I have in abundance.

The Raspberry Pi with connections on top of my Engineering Notebook.

The biggest part of this project is the Python program that I wrote. I am using an audio file from a text-to-morse audio converting website to create .wav files. Using the Raspi gives me the flexibility to play any type of audio file, and I can also access the GPIO port to control the radio or read switches. (For later revisions of the project…I’m thinking switches for different messages or a battery monitor to alert users the system is running low!)

Without going into step-by-step instructions on how I built it, the pictures should show a good representation of how this ammo can fox came to fruition. As of this writing I do not have the power supply in the box yet. Santa Claus is supposed to bring me that. I’m opting for a 12v/5v “security camera” power supply. The 5v will power the Pi, and the rest will run off the 12v side.

The Dummy Load

I built a 2.5 watt dummy load from ten 1/4 watt 510 ohm resistors soldered in parallel.  The case to hold the dummy load was 3D printed and has vents to allow heat to escape. While it’s just a theory, I am hoping that having the radio transmit into the dummy load might make it harder to find. I won’t be able to test this out in the field until I have the portable power supply. Carrying around the deep cycle marine battery isn’t any fun, and certainly expands the level of suspicion of a box with an antenna on it.

The Circuit

I had to look at a diagram for how the PTT and mic for the FT-60 worked. The system I devised might work for other radios if the jack is adapted for the other radios. I have a Baofeng that I would like to use, but the 3.5mm jack is wired differently AND I do not have a way to power it externally, yet. A battery eliminator is about $3 on eBay. A work around would be to use your radio’s VOX setting. In this case, you could EASILY omit this circuit altogether and just run an audio cable to a Baofeng (cheap).

I wired the circuit for my FT-60 on a “surface mount style” board. I used a Dremel tool to etch a few pads. I’m really liking how fast I can throw together a working prototype using this method. I used a 2-pin header to connect the interface to the Raspberry Pi GPIO using jumper wires.  (Hint: The schematic/wiring diagram is near the beginning of this long article.)

The 3D Printed Objects

The next thing I wanted to do was 3D print the other parts that I needed to mount the radio controlling circuit, the Raspberry Pi, and the radio into the ammo can. I haven’t had my 3D printer long, but I figured out how to use Tinkercad to create custom parts and learned how to download pre-designed stuff from Thingiverse. Piece of cake!

I printed four parts for the fox box: the dummy load housing, the Raspberry Pi case, the radio clip mount, and the interface box. It’s amazing what you can accomplish with a 3D printer. Having custom parts has never been so easy. All you have to do is design it or find it and print it. Boom!

A Raspi case modified and posted to Thingiverse by RichRap. The one I printed is black.

The Power Supply

The supply I chose for this project isn’t a gel cell like most use. I had a choice to make; I could use the 12v gel cell and make a 5v linear regulator or I could just buy a supply that had both power supplies already built. This one is by TalentCell on Amazon and sells for about $34. It is marketed towards LED strip lighting and CCTV cameras. It should fit perfectly in the fox box based on the dimensions. At 12V 6Ah, it should be able to power the fox long enough for simple hunts. Later on it might be cool to add a power connector to the outside of the fox so it can be charged without opening the ammo can. I probably have the parts for this is the garage. I’m leaving room for improvement.

The Working Prototype

I want to share the working prototype as a conclusion. This was my test program to see how things would work before actually putting the parts in an ammo can. I was using a big screen TV as my monitor so I could type the program. Proof of concept! Are you planning on making a fox box? Share your stuff in the comments below.


foxhunt.py file shared from my Drive