frater secessus

retired snowbird

written comms for the win

I boondock around the American southwest in a DIY campervan. I’ve always preferred time-shifted written comms to realtime comms like phone, chat, or meatspace conversations.1 And from a technical standpoint text is a lot more efficient than video, voice, fax, etc.

I ran a FidoNet BBS back in the day. I was interested in packet radio but got my ham Technician ticket too late – by then packet BBSes were basically extinct.

I keep hoping that smartphone-based mesh would take off because the devices are so prevalent, but no go. Briar, serval mesh, etc failed to thrive.

a wild viable (?) mesh appears

In the last year or so LoRa-based Meshtastic seems to have achieved critical mass. The devices are inexpensive and are not tied to Meshtastic. Fine, I’ll bite.

implementation

Based on my understanding of Meshtastic roles

client_base - on the roof

Since my steel-bodied campervan is something of a Faraday cage I needed an external node. I picked a solar powered, magnet mounted node built by etsy/eBay seller PeakMesh. It’s built around a RAK 4631 on a RAK19003 baseboard (NRF52) powered by an 18650 and ~1w of panel on an allegedly-MPPT control module. My camper’s house power has run on solar since 2018 so I’m well-accustomed to picking camping spots based on clear sun.

bottom view side view

Its crazy-strong neodymium magnets stick to an unused section of the camper’s steel roof rack, with a zipstrip “shock cord” safety. This will put the antenna about 9ft in the air. The antenna will blow over while in transit so I will put it back up when I arrive at another camping spot.

It’s not clear to me what happens to charging at freezing temps; maybe the very low charging C rate will be OK. Having a replaceable 18650 makes it a simple swap if it gets wrecked. Might end up wiring in a NO thermal switch into one leg of the solar input that only closes at ≥4°C.

client_mute - non-routing nodes

  • a “base station” made from a Heltec E290. I wanted a node with PSRAM so I could play with store & forward. I really only want the store function and the docs make it sound like this might work.[^apponly] I lurv e-ink; very easy on my old eyes. Cases are hard to come by for this board. I’ve made a crude one out of the case it came in and may look into 3d printing at a library or maker space. I left the crappy-but-included stub antenna on it since it only has to reach nodes in and around the van.
  • Rak Wishmesh Tag used in urban settings or other areas with developed mesh
  • a two-pack of Heltec V3 with the Playskool-aesthetic “L” cases and internal antennas. They will be used in the camper for experiments2 so they don’t need external ants or batteries of any kind.

[^apponly}: “Best to disable the heartbeat to reduce network traffic if you only want to retrieve it by connecting with an app to the server…” (emphasis added). This suggests that the >30 packet payload can be accessed by a client rather than a node. I haven’t been in an area with sufficient message packets to test this yet.

client - portable nodes to carry on hikes

  • a Heltec T114-based kit with case and 3Ah battery. Stock antenna replaced with one from Muzi. IMO the N36 case is an ugly duckling but it gets good reviews for feel and durability. And it holds a lot of battery.

MQTT

Although El Paso, TX is my adopted home base I am usually in Texas for a couple weeks in December. That’s when my annual V.A. medical checkups are scheduled. I also handle other Texas busines then: showing up in person when required for license renewals, etc.

Because of this I use MQTT to follow along with Texas traffic using Meshtastic MQTT Connect:

  • Meshtastic’s public MQTT server: msh/US/TX, Texas
  • Meshtastic’s public MQTT server: msh/US/TX, LongFast (usual PSK)

  1. I have rather serious anxiety, social and otherwise. Anything that requires me to make a Normal and Appropriate response on the fly is likely to go down in flames. Part of the reason I boondock is to be away from other people; Sartre and all that. ↩

  2. Could be used for MQTT since they have wifi. Or could be flashed to Meshcore, or left on Meshtastic but changed to MediumFast to see how much of that is out there. ↩