Maiden voyage was a flop. No tracks appeared at all – I’m not 100% sure if it transmitted, but I’ve had a feeling the audio was weak. Add to that that I had disabled the PTT the night before, and didn’t connected it until halfway through my day. oops.
Reconfigured the audio in the radio (filtered, squelched audio, companding, anything I could do to make it not flat). Next trial… eventually.
Got home, and my HC11 BLE module was in. Time to configure it. Turns out the HC11 is a bit more finicky than the others. It didn’t like commands from the Arduino console, but it did respond to the DSD tech console program on windows. Also responded OK to a different terminal program (didn’t like PuTTY… honestly, PuTTY is great for being free, but it’s obnoxious that it just kills the. process when it looses connection, and I have to restart the program to try again).
Annnddd… another brick wall. HC11 doesn’t have the ability to set custom services (GATT UUID stuff) like all the others. so it’s not a candidate for the KISS over BLE protocol.
Here’s where things stand as of now:
| Module | Bluetooth (PC/Mac) | BLE (iOS) | TTL Serial | AT Commands | GATT (128 bit UUID & CHARs) | ea. cost |
| Required? | – | ✅ | ✅ | ✅ | ✅ | – |
| HC05 | ✅ | 🚫 | ✅ | ✅ | ✅ | $4 |
| AT09 | (not tried) | ✅ | ✅ | ✅ | 🚫 | $3.50 |
| HC11 | 🚫 | ✅ | ✅ | ✅ | 🚫 | $11 |
| Adafruit BLE Friend | ✅ | Maybe | ✅ | ✅ | ✅* | $15 |
| Pmod BLE | ? | ? | ✅ | ✅ | ✅ | $24 |
I ran my troubles through AI to see if maybe I was just misinterpreting the protocols. It pretty much told me I was spot on – none of the modules I had in-hand would work. It also told me that my only options were going to be something ESP32 (I don’t want to learn ESP-32 just for this), or maybe something like the Digilent Pmod BLE. the Pmod looks promising – it’s a microchip RN4870/71 chipset, which DOES support GATT services (required for the KISS over BLE)… but will it talk to an iPhone? at $25, it’s the most expensive of the devices I’ve looked at thus far. I’d like to answer the iOS question before I order one… or maybe there’s a less expensive demo board for the RN4870/71 out there….
I got very close. The Bluefruit LE takes the GATT commands (AI complains about the CCCD values, but that’s not documented in the protocol). The Adafruit iOS utility can connect, but APRS.FI and other tools can’t see the device.
There’s another possible solution for all of this….but it’ll take a lot more coding and effort than I think I have time for.
The Arduino UNO R4 has both BLE AND wifi. In theory, (since it’s an ESP32 under the hood), it has the guts to do all of the tracker AND KISS work, AND it could serve as a TCP KISS TNC or BLE connected TNC.
Some day….