The brain moves to the phone
Third Eye Worldwide has decided: the second-generation kit drops the Jetson Orin Nano from its plan. The wearer's own smartphone, on a chest mount with its camera, carries the compute and the AI. The kit's microcontrollers, drivers, and vibration motors stay exactly where they are, and the phone is integrated with them across the isolation boundary the kit was designed around.
What the phone does
- Scene description, sign reading, naming things, and routes: the assistant layer, on demand, spoken or shown.
- The camera. A phone's ultra-wide lens on the chest covers the walking lane and both shoulders without moving parts.
- Logging: every frame, every buzz, every button press, so the first build is an instrument that can answer the program's open questions.
- The text home. The location and the heartbeat status that the first kit sent over a 2G modem ride the phone now: no modem, no SIM, no airtime to pay for.
- Later, the exploration display: the phone drives the 4 by 3 motor grid on the upper back, reading a room when the wearer stops.
How it is integrated with the kit
The phone talks to the kit's spine controller, the ESP32-S3, over Bluetooth Low Energy or a USB-C cable. The spine passes what the phone offers down to the reflex controller, the RP2350, as enrichment only. The reflex controller keeps the distance sensors, the drivers, and the little motors in one hard real-time loop that never waits on the phone, the radio, or the camera. The wire format is T.E.K.-Link 0.1, a 20-byte packet.
The rule from the first board review holds: the phone may add a buzz. It may never be the only thing that can cause one. Take the phone away and the belt, the collar strip, and the ankle bands warn exactly as before.
Why
- The wearer already owns the phone.
- Weight and power. A Linux computer and its camera draw 10 to 20 watts and need a laptop-class battery on the body. The kit's whole sensing stack runs on 1 to 2 watts, a pocket power bank, and the phone carries its own battery.
- Heat and failure. No Linux computer on the body means no boot time, no thermal budget, and one less class of software failure next to a safety device.
What changes on the parts list
The Jetson and the dedicated depth camera leave the plan. The phone mount with USB-C power pass-through, adopted in the first board review, comes in. The ESP32-S3's Bluetooth link becomes the phone's door into the kit.
What does not change
The three laws. The reflex loop and its share of under 5 ms. The belt, the collar strip, and the ankle bands. About 70 ms from the world to the skin for a hazard ahead and about 120 ms for the ground, modeled until the bench measures it. The milestones, G0 to G4.
Honest limits
A phone camera delivers a frame about 80 ms after the light arrives, so anything the phone says reaches the skin at about 130 ms; that is fine for reading a space and is why it is not in the warning path. On iOS the Bluetooth interval holds at 15 ms. A phone running its camera runs warm and drains; the app will show the wearer what it is costing. Phones differ from wearer to wearer, so the app must degrade gracefully. A dedicated onboard computer stays on the roadmap for the day the kit must work without a phone.
The camera is the wearer's choice
Everything a camera sees goes to the app on the phone, which is the intelligence of the kit. If the phone has a camera, the wearer mounts the phone on the chest and it does the looking. If they would rather use the phone as a phone, they switch that role off in the app and use a separate chest camera if they have one. If they have neither, nothing that matters is lost: the belt, the collar strip, and the ankle bands warn exactly the same, because the camera is never in the path that keeps a person safe.
The choice is left to the wearer on purpose. The kit must be buildable and affordable in a small city, in a village in Brazil, in a township in South Africa, by people who may not be able to afford every part at once.
Design review recorded the decision, and the site now says it wherever the brain tier is named.