Know your DotBot v3#
A quick tour of the hardware you’ll plug things into. This is orientation only - for the PCB, schematics, and CAD see the DotBot-hardware repo.
Three pieces make up a working setup:
The DotBot v3 - the robot. An nRF5340-based wheeled bot.
The gateway - an nRF5340-DK that bridges your computer to the swarm over the air.
A Lighthouse 2 base station - for indoor localization (optional, per-experiment).
Cables and connectors#
What to have on hand (the two USB cables are the ones you’ll reach for most):
Cable / connector |
For |
|---|---|
USB-C to USB-A (or USB-C) |
Flash and power the DotBot v3 (its USB-C port, J2). |
micro-USB to USB-A (or USB-C) |
The nRF5340-DK gateway’s on-board J-Link. |
Barrel-jack charger (2.5 mm, 6-18 V) |
Charges the DotBot v3 supercap (J4); free-roaming only. |
DotBot v3 - the robot#
The robot has two connectors you’ll use:
Connector |
What it’s for |
|---|---|
USB-C (J2) |
Flash and program the bot. Also powers it while plugged in. |
Barrel jack (J4) |
Charges the on-board supercapacitor (the bot’s “battery”). |
USB-C (J2) - flashing. The DotBot v3 has an on-board programmer behind the USB-C port: a J-Link-OB / DAPLink debug chip plus an SWD mux that routes the debug lines to the nRF5340. You do not need a separate J-Link for normal flashing - just a USB-C cable. Plug it in and flash:
# cabled flash of one bot (board defaults to dotbot-v3)
dotbot device flash dotbot -s 77
A standalone J-Link is only needed to re-flash the on-board programmer’s own
firmware (dotbot device flash-programmer) - a rare, one-time bring-up step.
See device for the full flashing workflow.
Barrel jack (J4) - charging. The barrel jack feeds the BQ24640 charger, which tops up the on-board supercapacitor (a ~240 F stack at 3.0 V max). The supercap is what runs the bot when it’s untethered; expect short, fast charges rather than a slow battery cycle.
Note
The bot is powered whenever USB-C is connected, so you can flash and bench-test without charging first. For free-roaming, charge via the barrel jack.
Gateway - nRF5340-DK#
The gateway is a stock Nordic nRF5340-DK with its own on-board J-Link (over the DK’s micro-USB port). It runs the Mari gateway firmware and bridges your host to the swarm radio.
# flash the gateway role onto a DK (writes the network id + both cores)
dotbot device flash-mari-gateway --swarm-id 0100 -f 0.8.0rc1 -s 10
# then run the host-side UART<->MQTT bridge
dotbot run gateway
Geovane’s serial-prefix convention: DotBot v3 boards start 77, nRF5340-DKs
start 10 (the -s prefix selects which probe to talk to). See
swarm for driving the fleet once the gateway is up.
Lighthouse 2 base station#
For position tracking, the testbed uses Valve Lighthouse 2 base stations. Each DotBot v3 carries an LH2 sensor shield (a TS4231 light-to-digital receiver with a photodiode) that decodes the base station’s sweeping IR beams into a position. One base station illuminates the arena; the bots compute where they are from what they see.
Once the optical setup is in place, calibrate it before relying on the coordinates - see LH2 calibration.
Next steps#
device - flash an app or role onto one cabled board.
swarm - control the whole fleet over the air.
DotBot-hardware - schematics, BOM, and CAD.