Keyboard, Buzzer, and New Antennas

Well then, this time I decided to add a few more things that I find interesting and useful. First, an external keyboard — so that text can be typed directly on the device rather than through the phone. That simplifies the whole communication process quite a bit. Second, it would be nice to actually hear when a message arrives. With the phone, the app tells you what came in and when, but without it you only get a brief flicker on the little screen — and if you happen to not be looking at it, you will never know. So a buzzer needs to be added. The board seems to support it. Third, I wanted to try antennas that do a better job transmitting signal. As I understand it, the bigger the antenna, the farther a message can travel. There are repeater options too, but I do not know how those work and I am not looking into them yet.

After a bit of searching online, there seems to be a solid and not too expensive candidate for the keyboard — the M5Stack CardKB. It is quite compact, and I found several examples of how to connect it to the Heltec V3. While searching for the keyboard I also came across a case that should fit both the Heltec V3 and the keyboard together. So if everything goes well, it should be possible to build a device that works completely without a phone, sending messages directly from it. As for the buzzer — the whole thing seemed simple enough. Almost every old toy had a beeper in it, and when it broke you would pull out the “useful parts”, and the buzzer was always one of them. Whether those parts ever actually get used is another question entirely — you end up with a bag of miscellaneous components that probably have a pretty slim chance of ever seeing daylight. But this time both the buzzer and a switch turned out to be genuinely useful. I also ordered slightly larger antennas to try to extend the communication range.

When assembling the device, it turned out that the case I found did not quite work for fitting both the Heltec V3 and the keyboard inside. The connector on the keyboard sits right on top and is fairly large. So one option was to desolder the connector and solder wires directly to the board without it. Unfortunately that process is not very easy — though it probably gets better with practice. While desoldering the connector pins, I accidentally tore off one of the pads on the keyboard’s PCB. Luckily there was a tiny bit of trace left, so I carefully cleaned it up and soldered a wire directly to it. I have no idea how reliable that is, but it works for now.

There was also a moment with the buzzer — soldering it in was easy and it fit inside the case just fine, but it absolutely refused to work. After a few hours of searching I figured out that you have to explicitly enter the pin the buzzer is soldered to in the Meshtastic app before it will actually do anything.

So after getting the buzzer configured, I disconnected Bluetooth and tried sending a message from one device to the other. And it worked! The buzzer beeped, the screen showed that a message had arrived, and I was able to read it. That was genuinely exciting — messages can now be sent without a phone at all.

Range has not been tested yet. And I have no idea how long the battery lasts either.

There are still a few ways to expand things further — adding a GPS module, for example, so the device’s location could be tracked. But for now all of that is still just ideas.

• External keyboard
• Buzzer
• Better antennas for extended range
• New case to fit all the components

Is this the end of the story? I don’t think so — but for now, it is all still at the stage of ideas and experiments.