The Z1 was a mechanical computer

Computer

A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...

 designed by Konrad Zuse

Konrad Zuse

Konrad Zuse was a German civil engineer and computer pioneer. His greatest achievement was the world's first functional program-controlled Turing-complete computer, the Z3, which became operational in May 1941....

 from 1935 to 1936 and built by him from 1936 to 1938. It was a binary electrically driven mechanical calculator with limited programmability, reading instructions from punched tape.

The Z1 was the first freely programmable computer in the world which used Boolean logic and binary floating point numbers. It was completed in 1938 and financed completely from private funds.