mowlark
3D render of Photon on a lawn

Photon

A mast to see further, a roof to charge from the sun.

GEN 2 20kg 3D render of Photon

Photon

Sentinel

A mast to see further, a roof to charge from the sun.

Concept · simulatedTwo-wheel differential, 1 caster
  • Cut36 cm
  • Top speed0.50 m/s
  • Peak rate648 m²/h
  • Range500 m²
  • Climb12°
  • Agility115 cm turn
  • Sight43 cm blind
  • Cost≈ $2.4k

Special Sees over long grass from 1 m up; its solar roof tops up the battery between missions.

Weakness Tall: low branches and wind. Its mast lidar has a 43 cm blind zone close in.

✔ Smoke test passed · 98.6%Full specs →

Gen 2 · Sentinel · Concept. Simulated.

Ion's body with a 1.1 m sensor mast and a 30 W solar roof. Up high, the lidar and camera see over long grass and low hedges, and the GNSS antenna has a clearer sky. The trade-off is a bigger blind zone close in: the lidar is tilted 30° down to keep it small. The roof tops up the battery between missions, so it can live away from a dock.

Photon is a concept: simulated, not built. Parts and prices are estimates, in US dollars (Nov 2026). Drawings are generated from the profile the simulator uses.

Body (L × W × H)61 × 60 × 115 cm
Mass≈ 20 kg
DriveTwo-wheel differential, 1 caster, 24 cm wheels, up to 0.5 m/s
Blades36 cm → 36 cm cut
Battery7S 6 Ah ≈ 151 Wh
Stripe spacing32.4 cm (10% overlap)
Edge lap35 cm from the edge; uncut band ≈ 17 cm for the trimmer
Turning in place sweepsa 115 cm circle
3D lidar blind zone43 cm ahead of the nose
Margin at raised beds45 cm
Best forLawns with long grass or low hedges; spots without a powered dock.
Slopesup to ≈ 12°

Drawings

◆ 3D lidar○ RTK GNSS antenna+ turning centre- - - blades
61 cm long × 60 cm wide
From above, nose to the right. Dashed blue: the circle the body sweeps turning in place round the + (its turning centre). Green band: the cut.
blind 43 cm115 cm tall
From the side. Dotted blue: the 3D lidar's lowest beam; anything 4 cm tall closer than that is unseen, so the stop field never shrinks below it.

Parts list

PartWhat it doesPriceSource
Everything in IonThe body, board, brain and sensors≈ $2,150–2,300Ion's list
Mast (carbon or aluminium tube) + mountsLifts the lidar, camera and antenna≈ $60estimate
30 W solar panel + MPPT charge controllerCharges between missions≈ $90estimate
Total≈ $2,300–2,450

Build plan

  1. Build IonEvery Ion step first.Test: Ion's checks pass
  2. MastMast and mounts; re-run the lidar's mount calibration.Test: Lidar pose within 1 cm / 0.5° of the profile
  3. SolarPanel and MPPT into the pack's charge input.Test: Charges at ≥ 15 W in full sun
  4. StabilityTilt test with the mast up.Test: Doesn't tip at 25° side slope