Vtech / Edu Toys: Venom
A real ball mechanism in a children's educational-computer mouse.
A mouse from the Window to Europe children's educational computer. The third most popular mouse with children at the Festival. Guess which one came second ^_^
Loads of children's computers used this form factor, most with mice. But almost all of those mice are dummies: just buttons at the end of a cable.
Here they made a fairly decent-looking ball mouse, albeit using old contact-encoder technology. Conductive strips on a disc pass beneath three feelers. When a strip bridges a pair, the contact closes and the mouse reads one increment of movement: one mickey, discussed in this earlier post.
Strips near the edge are offset, so the sequence in which the pairs close reveals the direction of rotation.
There is no signal processing inside the mouse. Button and encoder events travel to the computer along six wires and are processed by its software.
My youngest contact-sensor mouse dates to 1991, but this computer is marked 2003. By then, you could have built something more modern, and probably cheaper, using mass-market technology, though the software would need rewriting too. The ball is non-standard as well: smaller than those in familiar mass-produced Chinese mice.
The computer itself is amusing. It even has a Eurokey.
If anyone wants it for experiments, I can pass it on. Get in touch =)
