Building A Raspberry Pi Rover: My Big Fat Linux Weekend

Linux! Such a wonderful, rich, capable operating system has blessed us, and all for the low, low cost of absolutely free. It’s under the hood of countless servers, computers, phones, and embedded devices, and is the go-to solution for when you want to get the job done right. Why, then, does it curse me so?

Prologue

The penguin giveth, and the penguin taketh away.

My experience with the almighty penguin stretches back to the late 90s. Facebook hadn’t been invented yet, so most weekends were spent installing whatever came on the front of the latest computer mags. I wish I was kidding, but I’m really not.

Way back when, us kids would load the latest Red Hat or Fedora distribution onto our hand-me-down Pentium IIs, trying not to accidentally wipe our hard drive in the process. Limited to dial-up internet and very few help resources, it was pretty common that you’d spend hours watching progress bars tick over, only to wind up with no working mouse, or an X server that simply refused to start for man or God. Did I mention we did all this for fun?

Trying To Get Some Work Done

Of course, after growing up, real life and real responsibilities take over. Now, if I’m using Linux, it’s because I’ve got a job to do, not just because there’s nothing good to watch on Cartoon Network this weekend. I consider myself to be a fairly intermediate user. I’ve compiled a few things successfully, understood how to work with a variety of package managers, and once, just once, even managed to connect to a wireless network from the command line. There’s not a whole lot that phases me in this realm anymore.

For the past few years, I’ve been slowly working on a little rover by the name of TKIRV, powered by a Raspberry Pi. It was overdue for a camera upgrade, as I’d been using an old Microsoft webcam for far too long. I ordered a nice 1080p Raspberry Pi camera, and naturally the parts marinated in their boxes for a good couple of years. Finally, after much procrastination, I was eager to get my wheely boi back out on the road.

This was but the beginning my weekend slaying embedded Linux dragons.

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The Xerox Star On A Desktop Near You

It is 1980-something and you see someone typing on a keyboard. The display is graphical, and they use a mouse to finish a document, send it over the network to another similar computer, where another user edits it a bit and prints it on a laser printer. Given the time-frame you might think the computer is a Mac, but you’d be wrong. The Xerox Star had all the features Apple “invented” about three years before the Macintosh arrived. If you never heard of the Star, that’s not surprising. At $16,500 each, there were only about 25,000 sold. Your chances of finding a working one now are slim, but thanks to emulation created by [Josh Dersch] you can try the Star out on your hardware today. If you want a preview, have a look at the 1982 video, below.

The machine had a surprisingly complex architecture. The main CPU was a microcoded computer with multiple registers that would run a sort of microcode program to execute different instruction sets depending on what was running. In addition, there was an intel 8085 that loaded the right microcode and serviced the keyboard, the mouse, the floppy, and the serial ports.

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Truly Terrible Dimensioned Drawings

I’m in the planning stages of a side project for Hackaday right now. It’s nothing too impressive, but this is a project that will involve a lot of electromechanical parts. This project is going to need a lot of panel mount 1/8″ jacks and sockets, vertical mount DIN 5 connectors, pots, switches, and other carefully crafted bits of metal. Mouser and Digikey are great for nearly every other type of electrical component, but when it comes to these sorts of electromechanical components, your best move is usually to look at AliExpress or DealExtreme, finding something close to what you need, and buying a few hundred. Is this the best move for a manufacturable product? No, but we’re only building a few hundred of these things.

I have been browsing my usual Internet haunts in the search for the right bits of stamped brass and injection molded plastic for this project, and have come to a remarkable conclusion. Engineers, apparently, have no idea how to dimension drawings. Drafting has been a core competency for engineers from the dawn of time until AutoCAD was invented, and now we’re finally reaping the reward: It’s now rare to find a usable dimensioned drawing on the Internet.

This post is going to be half rant, half explanation of what is wrong with a few of the dimensioned drawings I’ve found recently. Consider this an example of what not to do.  There is no reason for the state of engineering drawing to be this bad.

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Ask Hackaday: DIY Handwriting Recognition

Computer handwriting recognition is very cool by itself, and it’s something that we’d like to incorporate into a project. So we went digging for hacker solutions, and along the way came up with an interesting bit of history and some great algorithms. We feel like we’ve got a good start on that front, but we’re stuck on the hardware tablet sensor itself. So in this Ask Hackaday, we’re going to make the case for why you could be using a tablet-like device for capturing user input or doing handwriting recognition, and then we’re going to ask if you know of any good DIY tablet designs to make it work.

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Retrotechtacular: The Mother Of All Tech Demos

Most bits of a computer we take for granted today – the mouse, hypertext, video conferencing, and word processing – were all invented by one team of researchers at Stanford in the late 60s. When the brains behind the operation, [Douglas Engelbart], showed this to 1000 computer researchers, the demo became known as The Mother of all Demos. Luckily, you can check out this demo in its entirety on YouTube.

Even though [Englebart]’s demo looks incredibly dated today, it was revolutionary at the time. This was the first demonstration of the computer mouse (side note: they call the cursor a ‘bug’), a chorded keyboard, and so many other technologies we take for granted today. During the presentation, [Englebart] was connected to the SDS 940 computer via the on-line system 30 miles away from Stanford. Yes, this pre-ARPANET, what is normally cited as the precursor to the Internet.

Sadly, most of [Englebart]’s researchers became disillusioned with the time sharing /mainframe paradigm shown in this demo. Those researchers wanted a more decentralized means of computing, so they went off to Xerox PARC where they helped create the first personal computers. Still, most of the ideas from 1968, such as the mouse, hypertext, and word processing, were in those little Xerox boxes.

On a more philosophical note, [Englebart] began his demo with the question, “If, in your office, you as an intellectual worker were supplied with a computer display, backed up by a computer that was alive for you all day and was instantly responsive to every action you had, how much value could you derive from that?” In the 44 years since this Mother of all Demos, we’ve gotten to the point where we already have a computer on our desks all day that is able to do any task imaginable, and it certainty improved our quality of life.

There are a few great resources covering the Mother of all Demos, including the Douglas Engelbart Institute’s history page and the Stanford Mousesite. Looking back, it’s not only amazing how far we’ve come, but also how little has actually changed.