Stan Meyer's "laser accelerator": the drive-by-wire pedal in a 1990 water car

Stan Meyer's water buggy had what he called a "laser accelerator": "attached to the accelerator pedal," developed "to translate from a mechanical displacement to an electronic displacement in order to allow the hydrogen computer system to produce the gas on demand" (1990 interview). The name sounds like science fiction, but the idea is drive-by-wire: no cable from pedal to engine, just a sensor reading how far your foot goes down and a computer deciding the power. BMW's V12 was among the first production cars to do it, in the late 1980s; today nearly every new car does, usually with two magnetic sensors in the pedal in case one fails. Stan needed it for a reason a gasoline car didn't: there was no tank of fuel to meter, so the pedal had to tell the electronics how much gas to make from water, right then. An electric car's pedal works the same way. His own schematic (Memo WFC 423 DA, Figure 4-4) shows how his worked: no laser, but a light-gate module of infrared emitting diodes (SEP8526) facing Optoschmitt light sensors (SDP8601), with a movable light-gate on the pedal cable sliding between them. A resistor ladder turns the position into a voltage and an LM131 turns that into a pulse frequency, 10 kHz at full scale. With no contacts to wear, Memo WFC 422 DA rates it at 100,000 hours, and if the LEDs lose power the hydrogen gas control shuts down. The full 1990 interview is on stanslegacy.com.

About the voices. The narrator is NeuralStan, an AI voice the archive uses for its made films. Where you hear Stan Meyer, it is Stan: every word of his is cut from an original recording, and nothing he says was synthesised.

Sources

• Stan Meyer at his garage · 1990 interview
• Stan Meyer, Memo WFC 423 DA, Figure 4-4
• Stan Meyer, 1990 interview at his garage, at 10:06 ("The laser accelerator control") and 33:42 — transcript on stanslegacy.com
• Stan Meyer, Memo WFC 423 DA, Figure 4-4: Laser Accelerator Control (light-gate module, SEP8526 emitters, SDP8601 Optoschmitts, LM131 voltage-to-frequency converter) — stanslegacy.com
• Stan Meyer, Memo WFC 422 DA (The Birth of New Technology, p. 46): light-gate between matched infrared devices, linked to the pedal by cable; no mechanical contacts, 100,000 hours; shut-down if the LEDs lose power
• Electronic throttle control (drive-by-wire): BMW's M70 V12 in the E32 7 Series was among the first production uses, late 1980s
• Accelerator pedal position sensors: two independent tracks (Hall-effect or potentiometric) for redundancy, standard on modern cars