Peter Balch - Home

A Wheeled Steampunk Mouse

How would a Victorian engineer make a mouse? You can't build an optical mouse with a mechanical difference engine. So you need wheels and mechanics.

My initial thought was that it should look like Mrs Coulter's carriage from The Golden Compass or like Leonardo da Vinci's cart.

Here are some early concept drawings.

It looks large but it's actually not much bigger than a standard desktop mouse.

Body length 111mm; Width 68mm; Height 57mm.

How it was made

Start with a USB ball-mouse. They are not too common. Ball-mice usually have the old PS/2 connector which no longer fits most computers and USB mice are generally optical. But if you search, you can find the occasional USB ball-mouse in a charity shop or car boot sale.

I wondered if there should be two wheels at the front or at the back so I built models out of Lego. It turns out that it's much more stable with them at the back. The mudguards are needed to stop your hand touching the wheels.
Take a photo of the pcb layout to trace the tracks if needed. Find the tracks that lead to the optical encoders and switches and make a note of the circuit.

Cut off the unnecessary parts of the pcb
Gears from a broken clock movement are used as wheels.
The back wheels are both the same size, the front wheel is larger.

The axles are made from brass tube. A coin is soldered near the middle to drive the wheel encoders.
Stripboard is used to support the encoder wheel, the LED and the sensor. One end of the shaft rotates in a washer held in place by brass wire. The other end is held in a slot bent out of brass wire.

A short length of rubber tube is fitted over the shaft. The coin fits in a slot in the PCB and a spring pushes it against the rubber tube.

One end of the shaft can slide in the brass slot and the rubber tube is held against the coin with a small spring.

Carefully bend the LED and the sensor leads so they point at each other and successfully encode the rotation.
The arrangement for the front wheel is similar. The wheel axles rotate in bearings bent from brass wire. They are prevented from sliding by collars soldered onto the axle tubes.
You can test the sensors by temporarily wiring them into the original mouse PCB.
The mouse wheel fits in a hinged carrier. Remove the rubber tyre and glue on a brass olive (used in plumbing). Some olives have a groove which looks very nice.
The carrier is hinged onto another piece of stripboard. The mouse wheel encoders and switches are soldered into place.
Pushbuttons are made from "Tactile Switches". The corners are filed off the plastic switch button and it then fits inside a 14mm brass olive.

Circular letters are printed and cut out of paper. They are covered with small circles of celluloid.

The buttons are mounted on PCBs made from yet more stripboard.
The bottom part of the mouse shell is made from papier mache. During construction, the mechanics are protected from the glue and are padded so that the shell won't touch the coins or encoder wheels.
After smoothing, painting and varnishing the result is quite good.
The sides and top are made out of old tinplate. Cardboard templates are made first then copied in metal. Tinplate is easy to soft-solder.

The tinplate is bent, soldered, filed, filled and smoothed.

The final coat of paint is red aerosol car paint with a light spray of black car paint while the red is still wet. It gives a nice textured appearance.

The coach lines are hand-painted in gold arcylic. It is then given several coats of varnish.

Two weeks later . . . . . . . How well does it work?

It's fairly comfortable to hold and can be used for most mouse tasks although it's a little more tiring than an optical mouse. It needs a mouse mat (in the same way that a ball-mouse does).

With a painting program, it's very easy to draw exactly horizontal and vertical lines - just lift the other wheels off the mat. Diagonal lines and circles are drawn OK: both sets of wheels will turn smoothly at the same time. Of course, it's never easy to draw a circle with a mouse.

Other projects:
Hacking an antique clock
Old Telephones
An Orrery-Clock
A steampunk mouse
A 1960s webcam
A sgian dubh memory stick
A wheeled mouse
An external disk drive
A 1930s webcam
A Vintage Intercom