The seventh kit in the How Things Work series. Two identical fax machines on one line: one reads a sheet line by line — a head with a sensor runs across the sheet, and every dot goes into the wire — and the other puts it with a pen on its own sheet the same second. You build the mechanics yourself, part by part: feed rollers, an angle drive, stepper motors, a carriage on a belt and limit switches. The brain is on ready CMOS 4000 chips (TI CD4029, CD4013, CD4017 and others): a stepper driver, a line, the whole sheet, a start bit, the Fine mode, the A5 format and one line for both. 52 chips, 4,344 transistors.
The introduction and lessons 0–1 are free; the rest opens after purchase.
2 MACHINES · 52 CHIPS · 4,344 TRANSISTORS