Automated Round-Bread Sentry
A static unit that watches a doorway, a counter or a picnic blanket, identifies round bread, and declines it on your behalf. It does not sleep. It does not negotiate. It does not eat.
| Compute | Raspberry Pi 5, 8 GB |
|---|---|
| Vision accelerator | Raspberry Pi AI HAT+ (Hailo-8L, 13 TOPS) on the Pi 5 PCIe portRuns a YOLOv8n detector at about 60 frames per second. A bun moves at 0 frames per second. There is headroom. |
| Camera | Raspberry Pi Camera Module 3 NoIR, standard 75° lensAutofocus locked at 0.4 m, the standard bun-to-sentry distance. |
| Illumination | 850 nm infrared, low power, mounted off-axis at 30–45° and diffusedBuns are frequently glazed. Glaze reflects. The lamp is angled accordingly. |
| Pan / tilt head | 2-axis aluminium bracket, MG996R size |
| Servos | 2× factory-waterproof digital metal-gear servos (Savox SW-0250MG or Rage B1224)Pointing accuracy about 0.3°. The required accuracy for a bun is about 3.6°. The Bureau over-specified. The Bureau always over-specified. |
| Servo driver | PCA9685 16-channel I²C board on its own 5–6 V supply |
| Countermeasure actuator | Heschen HS-1564B push-pull solenoid, 12 V, 20 mm stroke, 60 N, with return spring |
| Enclosure | IP65 box, cable glands, drip loops |
| Power | Mains via RCD, or 12 V LiFePO4 battery with 5–10 W solarDraws 7–10 W. Less than a toaster. Considerably less than a bakery. |
Each infrared frame is passed to the detector, which scores every object on two measures: roundness and a sesame-field classifier trained on the scattered eye. An object above a roundness threshold of 0.82 is logged as a suspect. A suspect with seeds is logged as a bun.
Detection is by shape, size and stillness, not by brightness. Buns are very still. That is how they get you.
Species reference: the Field Guide to Bun Species.
A one-time calibration grid maps every camera pixel to a pan and tilt angle. When a bun is identified, the head turns to face it directly. Eye contact is held for the full duration of the countermeasure.
The solenoid extends 20 mm and presents a small card reading "No, thank you." The card is held for three seconds and withdrawn. The bun is not touched. BunBot does not crush, throw or otherwise engage. Refusal is the countermeasure.
On repeated detection the card is presented again. There is no escalation. There is only repetition.
False negatives: none recorded. The croissant is not a false negative. The croissant has been ruled out.
One unit was completed before the Bureau was dissolved. Its whereabouts are not recorded. It is assumed to be still on duty.
BunBot is not permitted to crawl this website. See robots.txt.