Recently on the facebook uBitx ham radio group, there was a discussion about replacing the stock LCD screen with a touchscreen display that seemed to make running the thing easier, and displayed a lot more information. But, I didn’t want to risk my current radio by screwing around with it.
As luck would have it, someone was selling their uBitx radio kit, complete with enclosure, knobs, and partially assembled, for a lot less than the bare bones kits coming from India. He said he just didn’t have the time to mess with it. So we worked out a deal and I got his radio kit. I was pretty impressed with the little case, and there was room for other stuff.
The case came with a power supply to run it from 120v wall power, but since I always run the uBitx from a 12 volt supply, I left the wall supply out. On the right side, in the big clear space, I decided to put a computer case fan. Since the front of the box was clear, and everything else was blue, I got a PC fan with blue LEDs to light the whole thing up.
I also added the same power boosting board that I always use on the uBitx, to squeeze a bit more juice out of the power transistors. Right now its set up to feed the transistors with 20 volts instead of 12. They can handle up to 30, I think, but I didn’t want to tax them too hard. With 20volts in, they push right around 20 watts of radio power out, which is twice what the original output is set for.
In the front, you can see the hole for the original 16 character, 2 row screen. Thankfully it is easy to remove, as it just slots in with some pins. The replacement screen is by a company call Nextion, which makes touch-sensitive screens for a variety of industries. They even provide a simple programming interface. There is already a set of files for the little onboard computer that lets the screen and radio talk to each other. Someone else already did the hard work.
The uBitx is controlled by an arduino, a little computer on a chip that is often used to create simple projects and help people learn about programming and such. Its the little blue board to the right of the above pictures, and its not much bigger than a USB flash drive. The Arduino talks to the monitor through two wires, blue and yellow, above, through a serial port. The monitor has its own computer and control software.
Programming the Nextion screen was pretty easy. Again, most of the work had been done already by other hams and engineers, so all I really have to do is make backgrounds and move the click-boxes around so the old stuff and new stuff match up. The table above is the frequency change page, with all the little labelled click-boxes.
As popular as Star Trek and Star Trek computer stuff is online, it was really easy to make a new background in PhotoShop, put it into the programming interface, and move the click-boxes into position. My screen is bigger than the original, about 4.5″ versus the setup of 2.5″, so I had some extra room to play with on the sides of the images. Below was my first screen, completed. LCARS – for those not complete nerds, is Star Trek’s “Library Computer Access and Retrieval System”. Its basically their name for the computer system that runs the ship.
After finishing that screen, I did the main screen, which you spend most of the time looking at and running the radio from. After figuring out where I messed up and fixing several things, I uploaded the data to the display and waited. Then I rebooted it, and the Trexion display was born.
So there it is sitting on the desktop, the red light in the background is just the power light for the Arduino and its board. Unfortunately, the screen pulls more power than the little LCD, and it wasn’t long before I almost overheated the arduino’s voltage regulator. The screen started flickering, and I unplugged everything. So I had to get a 12v to 5v converter, which will mount next to the fan. I can power the screen separately from the arduino, which will keep it from burning out important stuff.
While I wait on parts and keep working on the case, I’ll redo a few more screens. There are at least two more common screens I want to work on, but there are about 5 I’ll almost never use.
This would make a decent road radio for car camping or even parking lot activations, but its too heavy and the power consumption is a bit much for backpacking. But its a fun engineering challenge.