EDSAC In Your Pocket

A simulation of a room filling valve computer from 1949. That fits in your pocket.


EDSAC In Your Pocket is a simulator of the EDSAC computer build by the University of Cambridge Mathematical Laboratory which was one of the first stored program computers and was operational from 1949 to 1958.


Hackaday.io project page

YouTube demo video

ESP8266 version demo video


All source code is licenced under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. The exception to this is the demonstration programs. These have been obtained from other EDSAC simulators and are, as far as I am aware, free to use. If you know that this is NOT the case then please let me know and I will remove them.

All other non-sourcecode files are licenced under CC BY-SA 4.0.

More details and the full licences can be found in the download (see below).


Source code and 3D printed parts download

Source code for ESP8266 port (no printed parts)


You can contact me through the Hackaday.io project page or just send an email to "edsac" at this domain.


This project would not have been possible without the following:

Martin Campbell-Kelly's EDSAC simulator (Windows, but can be run under WINE)

NISHIO Hirokazu's EDSAC on browser

The author would also like to thank The National Museum of Computing and specifically the museum members' club and the EDSAC Replica Project for the inspiration for this project.

EDSAC In Your Pocket

Copyright 2018-9 David Boucher