Custom assembled calculator

Made by Texas Instruments Inc, 1970.

John Billingsley is Professor of Robotics at the University of Southern Queensland. This calculator was made by Professor Billingsley using solid state and integrated circuits and a predecessor of the TMS 1000 chip, a LED display chip, and a keypad supplied by Texas Instruments for a client attempting to win a contract with Texas Instruments to design a circuit that would power the calculator using a single source so it could be used as a demonstrator model . Professor Billingsley successfully a...


This custom assembled calculator consists of solid state components mounted on a brown plastic matrix board; the whole construction is mounted on an amber-coloured Perspex board. The calculator is battery operated and has a finger pad, of which the numbers are totally worn off, for keying in data behind which the components are mounted - including a very early 28 pin processor chip which was a predecessor of the Texas Instruments TMS 1000 type developed in the early 1970s; and above the finger pad is an LED display . On the left side of the Perspex mount is a toggle switch for engaging the current. It uses early integrated circuits. Below the finger pad is an array of transistors, resistors and capacitors and green, red and blue insulated electrical wiring.

There are five extra chips.


70 mm
110 mm


Professor John Billingsley, Professor of Robotics at the University of South Queensland designed and built the calculator for a client who was attempting to win a contract with Texas Instruments - who had supplied a chip, LED display chip and keypad and wanted a circuit designed that would enable them to run it from a single power supply so it could be used as a demonstrator to potential customers. To power it, the calculator needed +9V and -5V. Professor Billingsley contributed a 'pumped diode' to the circuit to enable the calculator to get this from a single battery.
Texas Instruments Inc 1970


Gift of Professor John Billingsley, University of Southern Queensland, 2007
16 August, 2007

Cite this Object

Custom assembled calculator 2016, Museum of Applied Arts & Sciences, accessed 18 November 2017, <>
{{cite web |url= |title=Custom assembled calculator |author=Museum of Applied Arts & Sciences |access-date=18 November 2017 |publisher=Museum of Applied Arts & Sciences, Australia}}
This object is currently on display in Experimentations at the Powerhouse Museum.
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