classic hacks

2768 Articles

Building A Digital Scale From Scratch

June 12, 2013 by 13 Comments

duplo

[Raivis] was given a particular task at his university – find a way to measure how many Duplo bricks are stacked together. There are a number of ways to do this, everything from computer vision to using a ruler, but [Raivis] chose a much more educational method. He built a digital scale from scratch out of a strain gauge and a Wheatstone bridge. The build log is immensely educational and provides some insight into the challenges of weighing things digitally.

A strain gauge is a simple piece of equipment, just a small force sensitive resistor. When attached to a metal bar and a force is applied, the resistance inside the strain gauge changes, but not by much. There’s only a few micro Ohms difference between the minimum and maximum of [Raivis]’ load cell, so he needed a way to measure very slight changes in resistance.

The solution was a Wheatstone bridge, or four resistors arranged in a square. When one of the resistors in the bridge is replaced with a strain gauge, very small changes in resistance  can be measured.

With a custom ‘duino amplifier shield, [Raivis] can measure the resistance of his load cell with 10-bit resolution, or a maximum weight of 1.32 kg with a resolution of two and a half grams. A single duplo block weighs about 12 grams, so we’ll call this one a success.

Tamagotchi ROM Dump And Reverse Engineering

May 24, 2013 by 18 Comments

tamagotchi-rom-dump-and-reverse engineering

Often the true key to success is persistence and that holds true for this project which dumped the ROM from the current generation of Tamagotchi toys. If you’re a fan of learning the secrets built into consumer electronics — and you know we are — you’ll want to go back and watch the 24-minute lecture on Tamagotchi hacking which [Natalie Silvanovich] gave a 29C3 last year. She had made quite a bit of headway hacking the playable pods, but wasn’t able to get her hands on a full ROM dump from the General Plus chip on board processor. This update heralds her success and shares the details of how it was done.

As we learned form the video lecture it was a huge chore just to figure out what processor this uses. It turned out to be a 6502 core with a few other things built in. After prowling the manufacturer’s website she found example code for writing to Port A. She was then able to execute her own code which was designed to dump one byte of ROM at a time using the SPI protocol.

[Natalie] posted her code dump if you’re interested in digging through it. But as usual we think the journey is the most interesting part.

[Thanks Itay]

High Voltage Thor’s Hammer: Mjolnir At 80,000 Volts

May 2, 2013 by 43 Comments

[Thor’s] hammer, Mjolnir, is pretty freaking awesome. It can only be picked up by [Thor], he can use it to fly, and probably the coolest part, it can summon lightning. After watching the first movie, and goofing around with the guys at ArcAttack, I had this idea that I could stuff a tiny tesla coil into a mjolnir and end up with a really cool prop.

At this point, I had to make a decision. I was either going to go portable and live with small arcs, or make this a stationary piece and hide a giant tesla coil in a base. It would have bigger arcs, but I couldn’t carry it around.  While I may re-visit the stationary version at some point, I ultimately decided I wanted to be able to wander around and play with this thing.

I had seen some videos of [Staci Elaan] showing off her battery-powered coils and I really liked her results. I figured, with her experience, she could probably do a better job than I could on getting the most bang out of a small package.  She was happy to be involved and delivered a small 12v powered coil for me to work with. I should also point out that the coils [Staci] makes are usually donated to educational groups. This woman is awesome.

Continue reading “High Voltage Thor’s Hammer: Mjolnir At 80,000 Volts” →

Life Meter Gives A Real Life Measure Of Video Game Health

May 1, 2013 by 43 Comments

water-light-health-bar

This hack makes the virtual real by displaying your video game character’s health meter as a column of illuminated water.

The build video, which you’ll find embedded after the break, is really quite remarkable. The column is a clear piece of pipe anchored at one end by hand-tightened plumbing drain fittings. This allows [Bfayer] to attach a flexible bladder which he constructed for the project. An actuator pushes a hinged board up against the bladder to raise and lower the water level in the tube.

Alone that’s pretty impressive, but [Bfayer] went the extra mile and then some. He uses a four-way fitting at the bottom of the meter. One fork connects to the bladder, another allows air to be injected using an aquarium pump. The bottom of the fitting has a clear window so that an RGB LED array can shine into the water which was doped with highlighter ink to pick up the colored glow. To pull the whole thing together he coded the custom control interface seen above.

Continue reading “Life Meter Gives A Real Life Measure Of Video Game Health” →

Extending Old Games With Reverse Engineering And MAME

March 27, 2013 by 8 Comments

For last year’s Toorcamp, the folks over at DorkbotPDX helped out with the Church of Robotron installation. A religion founded on the prophesy of a cybernetic uprising in the year 2084 is a little esoteric even for us, so the Dorkbot crew wanted a way to make playing Robotron: 2084 a little more visceral. Using MAME and a few debugging tools, they were able to read the memory of a machine playing Robotron to extend the game into the physical world. When the player dies, lights go off, alarms sound, and the prophet of the Church of Robotron is pleased.

The setup at the Church of Robotron included a machine running MAME with a Robotron ROM. When events happened in the game, such as lasers firing or a player death, physical events would be triggered. To do this, the Dorkbot team read the memory locations of a game of Robotron at different times and found memory locations tied to in-game events. On their blog they go over using the MAME debug tool to detect a player’s death which can then be translated into physical apparitions for the Church of Robotron.

It’s a very cool hack, and one we wish we had a video of. Having a plastic ghost hit a player while playing Pac-Man seems like an awesome idea, and with the Dorkbot tutorial, it looks fairly easy.

Having Fun With Dumb Terminals

March 26, 2013 by 37 Comments

terminal

For a long time now, [Morgan] has been wanting an old serial terminal. In a stroke of luck, one of his pals at the Quelab hackerspace scored an awesome ADM-3A terminal from a collector. It’s a historically significant piece of computing and UNIX history, so obviously [Morgan] needed to get it working.

The ADM-3A terminal pre-dates the famous DEC VT-100 terminal, but since [Morgan]’s new acquisition speaks RS-232, he had a good shot at getting it to work with one of his more modern boxes. He’s using a Windows laptop loaded up with FreeBSD in a VM to talk to the terminal. Surprisingly, the only additional hardware required was a USB to serial cable and a DE9-DB25 serial adapter.

It may not be as cool (or as loud) as Quelab’s Teletype ASR-35 they have set up for Zork sessions, but it’s great to see ancient hardware have some
 use. Right now, [Morgan] is editing files with vi and of course playing Zork. Seems like there’s plenty of life left in this old dumb terminal. After looking for an old VT-100 for a while now, I’ve got to say I’m pretty jealous.