Arduino Brings USB Mouse To Homebrew Computer

When building your own homebrew computer, everything is a challenge. Ultimately, that’s kind of the point. If you didn’t want to really get your hands dirty with the nuts and bolts of the thing, you wouldn’t have built it in the first place. For example, take the lengths to which [rehsd] was willing to go in order to support standard USB mice on their 6502 machine.

Code for mapping mouse movement to digital output.

The idea early on was to leverage existing Arduino libraries to connect with a standard USB mouse, specifically, the hardware would take the form of an Arduino Mega 2560 with a USB Host Shield. There was plenty of code and examples that showed how you could read the mouse position and clicks from the Arduino, but [rehsd] still had to figure out a way to get that information into the 6502.

In the end, [rehsd] connected one of the digital pins from the Arduino to an interrupt pin on the computer’s W65C22 versatile interface adapter (VIA). Then eleven more digital pins were connected to the computer, each one representing a state for the mouse and buttons, such as MOUSE_CLICK_RIGHT and MOUSE_LEFT_DOWN.

Admittedly, [rehsd] says the mouse action is far from perfect. But as you can see in the video after the break, it’s at least functional. While the code could likely be tightened up, there’s obviously some improvements to be made in terms of the electrical interface. The use of shift registers could reduce the number of wires between the Arduino and VIA, which would be a start. It’s also possible a chip like the CH375 could be used, taking the microcontroller out of the equation entirely.

From classic breadboard builds to some impressively practical portable machines, we’ve seen our fair share of 6502 computers over the years. Despite the incredible variation to be found in these homebrew systems, one thing is always the same: they’re built by some of the most passionate folks out there.

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USB Mouse Hack For Pachyderm Protection

When most of us think of seismometers, our minds conjure up images of broken buildings, buckled roads, and search and rescue teams digging through rubble. But when [Subir Bhaduri] his team were challenged with solving real world problems as frugally as possible as part of the 2020 Frugal Science course, he thought of farmers in rural India for whom losing crops due to raiding elephants is a reality. Such raids can and have caused loss of life for humans and elephants alike. How could he apply scientific means to prevent such conflicts, and do it on the cheap?

Whether inspiration came from using a computer mouse with the cursor speed turned up to “orbital velocity” is debatable, but [Subir] set forth to find out if such sensitivity could be leveraged for the seismic detection of the aforementioned elephants. His proof of concept is a fantastically frugal low cost seismograph using an optical mouse and some cheap PVC pipe and fittings.

We invite you to watch the video below the break to find out how it works. You’ll be impressed as we were by [Subir]’s practical application of engineering principles. And keep your eyes open for the beautiful magnetic damper hack. It’s a real treat!

If pontificating pesky pachyderms p-waves piques your interest, perhaps you’ll appreciate previous projects which produce data with piezo pickups and plumbing parts.

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A Converter You Won’t Have: PS/2 Mouse To Serial Mouse

When did you last buy a mouse? Did it have a little adapter in the box? There was a time when if you bought a USB mouse, in the box was also an adapter to allow it to be used with the older PS/2 interface. And if you were to go back a few more years into the past, you’d have found when you bought a mouse with a PS/2 connector fitted, it may well have come with an adapter for a 9-pin RS232 serial port. Those mice from a decade or more ago would have contained the software to recognise the interface into which they were plugged, and emulate it accordingly. It is unlikely then that you could take a modern USB-only device and an unholy chain of USB-to-PS/2-to-serial adapters, and have it work as a serial mouse. Want to run Windows 3.1 on a 386DX? You need a serial mouse.

Happily, [matze525] has come along with a solution for those of you with a need to drive an ancient PC with a serial mouse. He’s created a PS/2 to RS232 mouse converter, and it takes the form of a little PCB with an AT90S2313P microcontroller to do the translation and an RS232 level converter chip.

It might sound like a rather unexpected device to produce, but we can see it fills an important niche. In the early 1990s mice were not the reliable optical devices we have today, instead they had nasty mechanical connections inside, or if you were extremely lucky, optical encoder wheels. The supply of still-reliable RS232 mice must therefore be dwindling, and if you have a Windows 3.1 PC to keep alive then we can see the ability to use a more modern pointing device has a lot going for it.

If you have one of those machines from that era that came with proprietary interfaces, maybe you can make use of a USB to quadrature converter.

USB Etch-a-Sketch-Style Mouse Is More Analog Than You’d Think

[Mitxela] wanted to build a different kind of mouse, one that worked like an Etch-a-Sketch toy with one X knob and one Y knob. Armed with some rotary encoders and a microcontroller, that shouldn’t be hard. But when you use a pin-limited ATtiny85, you are going to need some tricks.

The encoders put out a two-bit Gray code and close a button when you depress them. Plus you need some pins for the V-USB stack to handle the USB interface. [Mitxela] decided to convert the encoders  to output analog voltages using a simple resistor DAC. That would only require two analog inputs, and another anlaog input could read both switches.

One problem: there still wasn’t quite enough I/O. Of course, with AVRs you can always repurpose the reset pin as an analog pin, but you lose the ability to program the device at low voltage. And naturally, there’s a workaround for this too, allowing you to keep the reset pin and still read its analog value. You just have to make sure that value doesn’t go below about 2.5V so the device stays out of reset. Once that was in place, the rest went easy, as you can see in the video below.

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Victorian Mouse

If Babbage had started the computer revolution early, we might have seen a mouse like the one [Peter Balch] created. He started with the guts from a USB wheeled mouse and some gears from an old clock movement. In addition to the big wheels to capture X and Y movement, the mouse buttons look like the keys from an old typewriter.

mechanical-mouse-magicWe were afraid the project would require advanced wood or metal working capability, but the bottom of the mouse is made from paper mache. The top and sides are cut from tinplate. Of course, the paint job is everything.

The electronics part is pretty simple, just hacking a normal mouse (although it is getting harder to find USB mice with mechanical encoders). However, we wondered if it would have been as simple to use an optical wireless mouse. That would leave the wheels just for show, but honestly, most people aren’t going to know if the wheels are useful or just ornamental, anyway.

If you don’t feel like gutting a mouse, but you still want USB, you could use an Arduino or similar board that can simulate a mouse. We’ve seen quite a few of those in the past. Now all you need is a matching keyboard.

Mouse Pen From Old Parts

No offense to [Douglas Engelbart] but the computer mouse has always seemed a bit of a hack to us (and not in the good sense of the word). Sure we’ve all gotten used to them, but unlike a computer keyboard, there is no pre-computer analog to a mouse. There are plenty of alternatives, of course, like touchpads and trackballs, but they never seem to catch on to the extent that the plain old mouse has.

One interesting variation is the pen mouse. These do rely on a pre-computer analog: a pen or pencil. You can buy them already made (and they are surprisingly inexpensive), but what fun is that? [MikB] wanted one and decided to build it instead of buying it.

The main parts of the pen mouse include a cheap mouse with a failing scroll wheel, a bingo pen, and the base from an old web camera. There’s also a normal-sized pen to act as the handpiece. The project is mostly mechanical rather than electrical. [MikB] took the mouse apart and cut the PCB to fit inside the base. The rest of the build is a construction project.

The result appears to work well. [MikB] includes instructions for installing the mouse correctly in Linux. The net effect is like a tablet but doesn’t’ require much space on your desk. We’ve seen plenty of mouse projects in the past, of course. We’ve even seen hacks for a head mouse if that’s your thing.