Year: 2016

Mag Lev Without The Train (But With An FPGA)

June 26, 2016 by 4 Comments

It always surprises us that magnetic levitation seems to have two main purposes: trains and toys. It is reasonably inexpensive to get floating Bluetooth speakers, globes, or just floating platforms for display. The idea is reasonably simple, especially if you only care about levitation in two dimensions. You let an electromagnet pull the levitating object (which is, of course, ferrous). A sensor detects when the object is at a certain height and shuts off the magnet. The object falls, which turns the magnet back on, repeating the process. If you do it right, the object will reach equilibrium and hover near the sensor.

Some students at Cornell University decided to implement the control loop to produce levitation using an Altera FPGA. An inductive sensor determined the position of an iron ball. The device uses a standard proportional integral derivative (PID) control loop. The control loop and PWM generation occur in the FPGA hardware. You can see a video of their result, below.

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Restoring The Groundbreaking Xerox Alto

June 26, 2016 by 27 Comments

The Xerox Alto was a minicomputer that had a lot of firsts to its name: first GUI, first Ethernet connection, and first computer to use a laser printer. This is the computer that inspired Steve Jobs to build the Lisa. And this was built all back in 1973! So when [Ken Shirriff] and a team of other old-computer aficionados got their hands on one, you know they’d get to work.

[Ken]’s blog describes the start of what’s sure to be a long journey. It mostly describes the Alto system and locates its place in computer history, but there are some interesting sidelines as well — like how [Alan Kay] also basically outlined all of the functionality of the modern laptop / tablet along the way to the Alto; it was supposed to be an interim Dynabook.

Work on this grandfather-of-modern-computers is just getting started, and [Ken] and crew are dusting off the power supplies and cataloguing memory boards. You can be sure that we’ll follow along with this restoration project, and keep you informed.

Effortlessly Send Antenna Wires Skywards With A Spud Gun

June 26, 2016 by 29 Comments

The heroes of action films always make it look so easy. Need to climb a tall building? Simply fire a grapnel hook from a handy harpoon gun, it’ll always land exactly where you want it and gain a perfect purchase so you can shin up the rope and arrive at the top barely having raised a sweat. If Hackaday ran Q Branch, we can tell you, we’d make ’em work a bit harder. If only because nobody likes a smartass.

If you’ve ever had to get a real line over something tall, you’ll know it’s a lot more difficult than that. You can only make it work with the lightest of lines that you can then use to pull up something more substantial, and you would be amazed how poor a thrower you are when you’re trying to throw upwards. Try attaching fishing line to a weight, try a bow and arrow, and nine times out of ten you won’t make it. There’s a serious amount of skill and luck involved in this line-throwing game.

[WB5CXC] has an interesting solution to this problem, at least as far as the application of throwing antenna wires over tall obstacles. He’s made a spud gun from PVC pipe, powered by compressed air. It takes the form of a U-shaped tube with one side of the U being a pressure vessel separated from the other by a ball valve.. Place a close-fitting puck with your wire attached in the open side with the valve closed, pump the pressure vessel full of air with a bicycle pump, and open the valve to send both puck and wire skywards. He says it will clear 100′ trees, counsels the user not to go higher than 100psi, and warns that the speeding puck can be dangerous. We like it already.

We’ve covered many spud guns here at Hackaday in the past, but it seems this is the first wire launching one. We’ve had a steam one for example, or this bolt-action spud gun, but pride of place has to go to the spud gun to end all spud guns.

Via DXZone.

Arcade Track-Mouse

June 26, 2016 by 7 Comments

[Evan] always wanted a trackball for his arcade cabinet. It’s hard to play Missile Command with anything else, and Centipede with any other controller is just stupid. So he bought one, jury-rigged a mounting bracket for it, and then fried it by plugging the wiring harness in backwards. Doh!

But proving Edison’s famous statement that innovation is 1% inspiration and 99% having the right stuff in your junk bin, [Evan] dug deep and came out with one of twenty (!) old ball mice that he had purchased for just such an occasion. (Yeah, right.) Since a ball mouse is essentially an upside-down trackball, all that remained for him to do was reverse-engineer the mouse and swap its controller in for the busted trackball.

A simple hack, born of necessity, and well done. If you’re stuck with a crate of optical mice instead, consider turning them instead into optical laser rangefinders.

Hackaday Prize Entry: SunLeaf

June 25, 2016 by 13 Comments

If there’s one place where the Internet of Things makes sense, it’s agriculture. From vast fields of soybeans, corn, and a different variety of corn, to the backyard garden, knowing how much sun, and rain crops get can vastly increase yields. For their Hackaday Prize project, [Adam] and [Shane] are building  a board designed explicitly for plants. It’s called the SunLeaf, and it has all the sensors and radios a good remote sensing board needs.

The SunLeaf is built around an ARM Cortex M4 microcontroller with an ESP8266 module for WiFi connectivity. Sensors are important for any remote sensing board, and for this the guys are going with SeeedStudio Grove connectors, providing four UARTs, four I2C, and four analog ports.For remote sensing applications, you generally can’t rely on mains power, so SunLeaf includes a port for a solar panel and a battery charger.

Although this project was originally a redesign of [Adam] and [Shane]’s Hackaday Prize entry from last year, what they’ve come up with is a great device for data logging, autonomous control, and environmental sensing for anything, from farms to weather stations.

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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.

This Arduino Console Has 64 Bit Graphics

June 25, 2016 by 6 Comments

Numbers are wonderful things when applied to technical specifications. Take [Bobricius]’ handheld Arduino-based game console. With an 8×8 LED matrix for a display it’s not going to win any prizes, but while he’s pushing the boundaries of dubious specification claims he’s not strictly telling any lies with his tongue-in-cheek statement that the graphics are 64-bit.

Jokes aside, it’s a neatly done build using a DIP version of the Arduino MCU and all through-hole components on a custom PCB. Power comes from a CR2032 cell, and it includes three buttons and a small piezoelectric speaker. He’s implemented a whole slew of games, including clones of Pong, Breakout, and Tetris, and judging by the video below it’s surprisingly playable.

Now you might look at this console and wonder what the big deal is. After all, there are plenty of similar designs to be found, and it’s nothing new. Of course, it’s a neat project for any hacker or maker, but we can see that this would make a great starter project for the younger person in your life who wants to try their hands at building something electronic. All through-hole construction for easy soldering, and a neat game at the end of it all.

He’s posted a full write-up of the design process as well as the hackaday.io page linked above, so if you fancy building one yourself there’s nothing to stop you too squeezing 64 bits of graphical goodness from an Arduino.

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