Prototype Communicator Complete

A project log for Jebel: Off Grid Communications

Jebel is a LoRa based text communication system for humanitarian and disaster relief situations.

chris-lowChris Low 08/02/2019 at 07:570 Comments

My first prototype messenger device is finished. It actually feels quite nice in the hand. I think the touch screen is about the right size, though I would love to find a capacitve touch instead of a resistive touch. 

The case is a "waterproof" tackle box. I did throw it in a tub of water. It floats and keeps out water, but I wouldn't rate it for submersion. The inserts that hold everything in the box are 3d printed in PETG. The display is a 3.5" Nextion display with 320x480 resolution. The microcontroller running the show is an ESP32 right now I am using a TTGO T-beam which has an ESP32, SX1276 Lora module, NEO m6 GPS module and battery management all on one board. I have also added a buzzer rgb led slider on/off switch, charging port, and a 2000mah lipo. 

While all the hardware is working assembly is too fiddly at the moment. I am still deciding which direction to go for the next revision. I will probably roll my own board, specifically because I want to utilize the new more efficient Lora chips. I have some modules using the sx1262 chips that I am looking forward to trying out.

I really love the way the antenna pops out on this unit, but I need to find some better antenna, because these ones are monopoles that really need a ground plane, and the vswr goes through the roof when they are in the case. I rebuilt one turning it into a coiled diplole which works better, but I need to find a reliable supplier for them.

All in all I am happy with the unit as a prototype, but it needs a lot of rework before it would be ready for even a small production run. 

On the software side everything works, but needs a lot of tidying up. I have also not done anything yet to optimize battery life.