First Lego Robot (1989) in history

Documented on the Internet. Developed by Marc Farssac in 1989 at the age of 17 programmed in Basic & "Machine Language" (ASM) and TTL electronics

Programmable Robot , custom TTL electronics, & an Apple][ with 64Kb

The "Interdepartamental Comission of Reasearch and Technology Innovation" (CIRIT, link) (Generalitat de Catalunya, Government of Catalonia) awarded Marc Farssac in 1990 for the Programmable Lego Robot. Using 4 Digital Inputs and 2 Analog Inputs the program allowed the user to record movements and repeat them.

Written by Marc Farssac. Last Updated October 21st 2022

The Robot is an extensible arm with three motors movement in two axes, controled by 4 bits and the analog inputs of earlier joysticks. It allowed to record the movement defined by the user and repeat it. Some challenging difficulties were found both on the electronics side and in the code.

The four bits were used to address each of the three motors, set their left / right direction and start / stop.

In his mind, Marc Farssac had enough bits to perform three activities of three motors. He wanted to set 9 different states and with four bits, he could (he was thinking) address up to 16 (2 power 4).

So, for example:
- 2 bits to determine which motor to apply the on/off & left right. (00 = motor 1, 01= motor 2, 10 = motor3)
- 1 bit (0 = left and 1 = right)
- 1 bit (0 = off and 1 = on)

In his mind, he had still one spare address (motor 11), so he could even have a fourth motor.

However, this was not working well. Suddenly something very strange was happening that drove Marc Farssac crazy.

His Phisics professor, who had not time enough to go into the robot and electonic details appointed the reason. There were parasit currents.

However, this was not the reason of that strange behaviour. What happened to Marc Farssac and how did he solve it?

YouTube video

Marc Farssac developed the electronics, the Lego Robot and the software in 1989.

Marc Farssac shakes hands with the President

Awarded Diplom


Marc explains the electronics

Lego arm with RS-232 cable pinout

Blocs diagram

TTL electronics

Full setup. Arm, Electronics, Apple ][ and DC power supply

Apple ][ screen with two 5.25 inches floppy disks drives underneath

Marc Farssac collects award from the hands of Honourable Sir Jordi Pujol, President of la Generalitat de Catalunya

Entrega de premis a la Generalitat de Catalunya

marc farssac president generalitat de catalunya palau de la generalitat
Marc Farssac shakes hands with the President of la Generalitat de Catalunya, Honourable Sir. Jordi Pujol during the award ceremony that took place in El Palau de la Generalitat on December 22nd 1990.

On the left of the image Sr. Heribert Barrera, Vicepresident of la CIRIT (wikipedia). On the right Sr. Artur Bladé i Font, Secretari of la CIRIT

Diplom awarded

Diplom awarded by La Generalitat de Catalunya and the Interdepartamental Comission of Research and Technology Innovation.

Diplom awarded by the Interdepartamental Comission of Research and Technology Innovation, Generalitat de Catalunya

The Diplom awarded by CIRIT, Interdepartamental Comission of Research and Technology Innovation. The Diplom is signed by the President of La Generalitat de Catalunya, Honourabe Sr. Jordi Pujol, Sr. Josep Laporte, President of CIRIT>, Sr. Heribert Barrera (Wikipedia) and Sr. Artur Bladé i Font, Secretari of la CIRIT

Marc Farssac
Interim Android
Developer & Team Leader

Let's talk now !
+34 644 22 00 88

Get in touch

Marc Farssac

WeWork - Espai d'oficines i coworking
Carrer de Tànger 86
08018 Barcelona
Catalonia, Spain

E-Mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Mobile: +34 644 22 00 88
Landline: +34 93 460 86 39

© Marc Farssac. All rights reserved.
Legacy site
Find my apps on the Google play store