general purpose

3 Articles

An Arduino From The Distant Past

February 6, 2019 by 20 Comments

Arduinos are a handy tool to have around. They’re versatile, cheap, easy to program, and have a ton of software libraries to build on. They’ve only been around for about a decade and a half though, so if you were living in 1989 and wanted to program a microcontroller you’d probably be stuck with an 8-bit microprocessor with no built-in peripherals to help, reading from a physical book about registers and timing, and probably trying to get a broken ribbon cable to behave so it would actually power up. If you want a less frustrating alternate history to live in, though, check out the latest project from [Marek].

He discovered some 6502 chips (Polish language, Google Translate link) that a Chinese manufacturer was selling, but didn’t really trust that they were legitimate. On a lark he ordered some and upon testing them he found out that they were real 6502s. Building an 8-bit computer is something he’d like to do, but in the meantime he decided to do a project using one of these chips as a general-purpose microcontroller similar to a modern Arduino. The project has similar specs as an Arduino too, including 8kB of RAM memory, 8kB of I/O address space, and various EPROM capabilities. [Marek] went on to build a shield board for it as well, for easy access to some switches and LEDs. It’s a great build that anyone interested in microcontrollers should check out.

Keep in mind that an ATtiny45 has 8 bits like the 6502 but only costs around $1 USD, whereas a 6502 would have cost around $200 in today’s dollars. It’s really only in modern times that we can appreciate the 6502 as a cheap 8-bit microcontroller for that reason alone, but we can also appreciate how it ushered in a computer revolution since competing Intel and Motorola chips cost around six times more before it showed up. They became so popular in fact that people still regularly use them to build retrocomputers of all kinds.

GPS And SDR Combine Forces

June 25, 2016 by 33 Comments

Software-defined radio (or SDR) is a relatively new (to average tinkerers, at least) way of sending and receiving radio signals. The interest in SDR exploded recently with the realization that cheap USB TV tuner cards could be used to start exploring the frequency spectrum at an extremely reduced cost. One of the reasons that this is so advantageous is because of all of the options that a general-purpose computer opens up that go beyond transmitting and receiving, as [Chris] shows with his project that ties SDR together with GPS.

The goal of the project was to automatically tune a radio to the local police department’s frequency, regardless of location. To do this, a GPS receiver on a computer reports information about the current location. A JavaScript program feeds the location data to the SDR, which automatically tunes to the local emergency services frequencies. Of course, this relies on good data for what those frequencies are, but this is public information in most cases (at least in the US).

There are a lot of opportunities here for anyone with SDR. Maybe an emergency alert system that can tune to weather broadcasts if there’s a weather alert, or any of a number of other captivating projects. As for this project, [Chris] plans to use Google’s voice recognition software to transcribe the broadcasts as well. The world of SDR is at your fingertips to do anything you can imagine! And, if you’re looking to get started in it, be sure to check out the original post covering those USB TV tuner dongles.

Multipurpose Robot For The Masses

June 8, 2016 by 13 Comments

As the cost of almost every technology comes falling down, from electronics to batteries to even tools like 3D printers, the cost to build things formerly out of reach of most of us becomes suddenly very affordable. At least, that’s what [John Choi] has found by building a completely DIY general purpose robot for around $2000.

OK, so $2000 isn’t exactly “cheap” but considering that something comparable (like Baxter) costs north of what a new car would cost means that [John] has dropped the price for a general-purpose robot by an order of magnitude. And this robot doesn’t skimp on features, either. It has a platform that allows it to navigate rooms, two manipulating limbs with plenty of servos, a laptop “head” that allows for easy interface, testing, and programming, and an Arduino Mega that allows it to interface with any sensors or other hardware with ease. It’s also modular so it can be repaired and transported easily, and it uses open source software and open hardware so it’s easy to build on.

This robot is an impressive piece of work that should help bring this technology to more than just high-end factories and research labs. They’ve already demonstrated the robot watering plants, playing the piano, picking things up, and many other tasks. We’d say that they’re well on their way to their goal of increasing the number of students and hobbyists who have access to this technology. If the $2k price tag is still too steep, though, there are other ways of getting into robotics without diving headfirst into a Baxter-like robot.

Continue reading “Multipurpose Robot For The Masses” →