Ghost Hand

@@ -96,8 +96,10 @@ The emitters' half-intensity angles are +/-28 degrees (VSMY2853SL, 850 nm) and +/-25 degrees (VSMB2948SL, 940 nm), and the VEMD2023 photodiode's is +/-35 degrees, so the beams are wide enough that the tilt only has to point them roughly. Signal falls as 1/d<sup>2</sup>, so the far placement is the one that limits: rev 2 tilts-**5 degrees**, which aims the beam axis at the window from 350 mm and gives the best worst-case margin-over 100 to 350 mm (6.5x a hand at 5 degrees, 6.4x flat, 6.1x at rev 1's 12).+**5 degrees**, which aims the beam axis at the window from the far end. The best worst-case margin over+100 to 350 mm is at 4.25 degrees for the 40 mm window; 5 degrees is within a fraction of a percent of it and a+little better for the 56 mm units (6.5x a hand at 5 degrees, 6.4x flat, 6.1x at rev 1's 12;+6.3x, 6.0x and 6.2x on 56 mm units). The case is built at 5 degrees. The emitter resistors also dropped from 12 to 8.2 ohm for more margin at the off-axis spots.  | Window to lens | Window elevation (40 mm) | 940 nm beam at 0 / 5 / 12 degrees tilt | Echo margin at 5 degrees | Elevation (56 mm units) | Margin at 5 degrees (56 mm) |@@ -387,7 +389,7 @@ The rev 2 case is being built now, about half of rev 1's footprint and much lowe  ## Firmware -Plain C for the ATtiny1616, updated for rev 2 (the STATUS dot takes the logo's job at about half the drive, a 30 mA light cap for the small cell, the 77 mA charge), updated for rev 2 (the STATUS dot takes the logo's job at about half the drive, a 30 mA light cap for the small cell, the 77 mA charge), updated for rev 2 (the STATUS dot takes the logo's job at about half the drive, a 30 mA light cap for the small cell, the 77 mA charge), updated for rev 2 (the STATUS dot takes the logo's job at about half the drive, a 30 mA light cap for the small cell, the 77 mA charge) (avr-gcc, about 13.1 KB of the 16 KB flash). The echo path is pure hardware:+Plain C for the ATtiny1616, updated for rev 2 (the STATUS dot takes the logo's job at about half the drive, a 30 mA light cap for the small cell, the 77 mA charge), updated for rev 2 (the STATUS dot takes the logo's job at about half the drive, a 30 mA light cap for the small cell, the 77 mA charge), updated for rev 2 (the STATUS dot takes the logo's job at about half the drive, a 30 mA light cap for the small cell, the 77 mA charge), updated for rev 2 (the STATUS dot takes the logo's job at about half the drive, a 30 mA light cap for the small cell, the 77 mA charge), updated for rev 2 (the STATUS dot takes the logo's job at about half the drive, a 30 mA light cap for the small cell, the 77 mA charge) (avr-gcc, about 13.1 KB of the 16 KB flash). The echo path is pure hardware: AC0, the event system and TCB0/TCB1 single-shots. The CPU runs the state machine, the learner, the lights and the safety checks, and a 1 s watchdog guards the main loop. Full source is in [firmware/](firmware/README.md), with a host test that runs the learner against simulated faucets