TopoKin
Vehicle radio
A Meshtastic radio that lives in the car: it rides on car power, has a real antenna on the roof, and shows the group where the vehicle is. Height and antenna matter more than radio power, so a roof antenna at the trailhead beats a stronger radio on the dashboard.
Every radio in the group already relays for the others, so this isn't required. It helps because of where it sits (high, with a good antenna) and because it marks the way back.
Prices and stock haven't been checked; they change.
Shopping list
| # | Part | Why | Links |
|---|---|---|---|
| 1 | RAK WisBlock Meshtastic Starter Kit, US915 (RAK19007 base board + RAK4631 core) | The radio. Meshtastic is preinstalled; includes the internal-to-SMA antenna lead. Same chip family as the Wio Tracker L1, so it uses very little power. | RAK store · Ameridroid · Maker Shed |
| 2 | RAK12500 GPS module | So the truck shows where it's parked. Clips into slot A; Meshtastic finds it automatically. | RAK docs · PileupDX · Meshtastic: supported add-ons |
| 3 | Waveshare 868/915 MHz magnet-mount antenna (5 dBi, SMA male, 3 m cable, IP65) | Goes on the roof and plugs straight into the kit's SMA port; the 3 m cable runs into the cab through the door seal. | Waveshare · alternative: 2J 2J3915M-915 (DigiKey) |
| 4 | 3.7 V rechargeable battery with a JST-PH 2-pin connector, flat, about 1000 mAh (fits about 55×34×6 mm in the box below) | Keeps it running when the car is off and the USB port goes dead. Check + and − against the board before plugging in: these connectors aren't standardized. Li-ion/LiPo 3.7–4.2 V only. | Any good source; board notes: RAK19007 |
| 5 | USB-C car charger and cable | Powers it and charges the battery while driving. | Any |
| 6 | Optional: RAK Unify Enclosure (100×75×38 mm) or the WisMesh Unify version | A tidy, weatherproof box with room for the flat battery under the plate. | Unify 100×75×38 · WisMesh Unify |
| 7 | Optional: 3D-printed window mount | Antenna outside the window, radio just inside, no cable through the door seal. | Printables |
Rough total: about $100 (kit roughly $40–50, GPS about $20–25, antenna, battery).
Putting it together
- Clip the RAK12500 GPS into slot A of the base board.
- Plug in the battery (after checking polarity).
- Connect the kit's antenna lead to the SMA port and screw the roof antenna onto it. Never power the radio without an antenna attached: transmitting into nothing can damage it.
- Antenna in the middle of the roof (a metal roof works as its ground plane). Run the cable through the rear door seal.
- Radio under a seat or in the glovebox, not on the dashboard: summer heat there isn't safe for the battery.
- Plug in the car USB.
Setting it up in TopoKin
Works today with no extra features: hand it out as a tracker named "Truck" (Group › Radios › Trackers › Hand out a radio, with it near your phone the first time). It joins your group's channel, reports its GPS position and battery, shows on everyone's map and every tracker's screen as "Truck", and relays messages for anyone in range like any other radio.
Later (#85): a proper Vehicle type with router mode (relays first), a 🚙 icon, and "on car power" instead of a battery level.
Other options
- Station G2 (high power, 12 V, rugged SMA): known for range; about $100–130 and often sold out. Tindie · maker's shop · Meshtastic docs. It can transmit well above the US license-free limit: keep it at about 30 dBm (1 W) or below for the encrypted group channel (more legally needs a ham license, and ham mode doesn't allow encryption). A documented car build: Meshtastic forum.
- WisMesh 1W Booster kit for more output from the RAK platform: Ameridroid.
- Higher-gain roof antennas are often N-type (needs an N-to-SMA adapter and a short cable): Taoglas TI.16.5F11 · Rokland 5.8 dBi kit · printable N-type mag mount.