Reverse-engineering old Finnish metro station displays

This project definitely was a patience tester. As the control system of the Helsinki metro was (and still is) under big renovation, [Konsta] could buy three old information displays for a very cheap price (5€ each). However, these displays came with no information whatsoever about the way to drive them, thus starting a long reverse-engineering journey.

[Konsta] started by taking one apart, discovering that each side of the display was composed of 10 daisy-chained LCD screens and some kind of control box. As you may have guessed, the key to reverse engineering the display was studying the contents of this box. It turned out that the control electronics were composed of an 8085 CPU, some RAM, a peripheral I/O chip, an UV-erasable EPROM chip (containing 32KB of program memory) and an EEPROM.

[Konsta] used an AVR to dump the memory contents of the two latter chips and it was at this part of the project that the Helsinki Hacklab joined in. Together, they reverse engineered the control PCB, studied the assembler code, sniffed the different on-board buses to fully understand how the display could be controlled.

We strongly recommend reading [Konsta]‘s writeup, especially knowing that he made this english page just for us!

Building an entire pinball machine from just the playfield

It all started  when [Iancole] bought a Fireball Home edition playfield on some famous auction website for $135. Originally, he had the intent of lighting the lamps with an Arduino, framing it, and hanging it on the wall of his office — which often happens with old pinball parts. But then his boys asked if he “could make it play”.

[Iancole] managed to find the pinball schematics online and started designing the electronics required by the many LEDs, solenoids and switches. As the LEDs and switches are on the same matrix, he chose a simple Arduino to cycle through them, giving the player the impression that the lights are constantly on. [Iancole] originally planned on using his raspberry Pi to control the solenoids, but he later switched to another Arduino because of the precise timing required.

Therefore, his Pi was used as the heart of the machine. It is interfaced to the two Arduinos to read states and send commands while running the game program, displaying HD graphics on a 24″ screen, playing music and game event sounds. All the electronics are proudly displayed on the backbox, and many developments are planned for it. Also, the machine will be on display at the Orlando Mini Maker Faire on October 5th!

Controlling Chromecast: AirCast APK released

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[Koush] is at it again, this time releasing AirCast, an Android app that’ll push videos to the Chromecast from Dropbox, Google Drive, and your phone’s Gallery. Astute Hackaday readers will recall that AirCast has been around for a few weeks now, but limited to only his whitelisted Chromecast. As [Koush] explains it, he had to reverse engineer the protocols and now he simply avoids the Chromecast SDK entirely. If you’re lucky enough to have a Chromecast, you’ll want to hurry and grab the APK (direct download link) and have some fun with it before it self-destructs. [Koush] isn’t ready to release it for more than a 48 hour period, but we encourage you to take advantage of AirCast and contribute to his call for feedback, bugs, and crash reports. You have a little under a day left.

See “AllCast” work its magic in the video below. No, that’s not a typo. Apparently [Koush] has been struggling with available names for the app, and you’ll hear him call it “AllCast” in the Youtube video. That name was taken for some other product, though, and “AirCast” has now replaced it. If you suddenly regret not immediately ordering a Chromecast and are sitting this one out, go read [Mike's] rant and get psyched up for when they’re back in stock.

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Adult sized baking powder submarine

baking-powder-submarine

It really doesn’t matter what age you are, we’re sure you remember baking powder submarines. That’s because cereal manufacturers have been including them as prizes since the advent of injection molded plastic. Fill them with baking soda and take them in the bath with you. They gently dive and surface. The problem is that the cereal prizes were tiny. Now you can relive your childhood with an adult size version of your own making.

The submarine is basically a hunk of PVC with a conning tower to keep it upright and a chunk of hose into which the baking powder is placed. The idea is that the powdery acid and base that makes up the stuff reacts when hit with water. This gives off a bit of carbon dioxide, which makes the sub float to the surface until the bubble escapes and is replaced with water to again sink the ship. The difficult part is to find the right buoyancy (using wine bottle cork) so that the bubble is all it takes to oscillate between the surface and the watery depths.

Watch it go in the video after the break.

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NESPo: another 3D printed portable NES

portableNESSide2

Grab your favorite cartridge and violently blow into the end, because [Dave Nunez] is sending us on a nostalgia trip with his 3D printed portable NES. He takes the typical route of chopping up a Nintendo on a chip (NOAC) retro machine rather than sacrifice a real NES, and opts for a NiMH battery over lithium (which isn’t a bad idea; they can burst into flames if you charge them incorrectly). The battery life is, however, tolerable: 2.5 to 3 hours.

All the components are packed into a custom-made 3D printed PLA enclosure, which [Dave] kindly shares on thingiverse. He also decided to 3D print each of the buttons and their bezels/housings, which he then topped off by cutting acrylic sheets that seal up the front and back. As a final touch, [Dave] slips in some custom art under the acrylic and mounts a printed LED nameplate in the corner.

We’ve seen [Dave's] work at Hackaday before, when he built a one-size-fits-all-consoles arcade controller.

On not getting metal fume fever with galvanized conduit

galv

You can find galvanized steel pipes at Home Depots and construction sites all around the world. These relatively thin-walled steel pipes would make for great structural members if it weren’t for the fact they were covered in a protective layer of zinc. This layer of galvanization lends itself to crappy welds and some terrible fumes, but badass, TV personality, and hacker extraordinaire [Hackett] shows us how to strip the galvanization off these pipes with chemicals available at any hardware store.

Since the galvanization on these pipes covers the inside and the outside, grinding the small layer of zinc off these pipes is difficult at best. To be sure he gets all the zinc off this pipe, [Hackett] decided to chemically strip the pipes with a cup full of muriatic acid.

The process is simple enough – fill a cup with acid, dunk the ends of the pipes, and clean everything up with baking soda. A great way to turn scrap pipe into a usable material, make a cool paper mache volcano, and avoid ‘ol galvie flu

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[Lou] puts invisible fence inside and outside his home

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Leave it to [Lou Wozniak] to go beyond ordinary when installing invisible fencing. Invisible fence is an electronic system that contains your dog by triggering a shock collar. The install requires a loop of wire to generate a field detected by the collar.

[Lou] starts off by buying a do it yourself kit. He has previous experience with this (check out his battery hack for the collars) and found that the cheap solid core wire didn’t hold up to animals and shovel accidents. He headed down to the hardware store and came back with a spool of stranded wire with extra thick insulation which should hold up much better.

The image above shows the model he built to plan for the installation. He’s not just making a single area in the yard. Look closely and you’ll see he’s going to use it to keep the dogs out of the dining room as well. This loop will be installed just below the floor from the basement.

With planning behind him he doesn’t fail to innovate with the installation technique. He recommends an angle grinder with a diamond blade to cut the slot for the wire in your yard. The one caveat being that you need to wait until the yard is super dry or it will muck up the blade. Dry dirt creates a lot of dust, but he uses a leaf blower or floor fan to blow it away from him as it works. To help minimize the amount of shocks the dogs receive while learning their new area he placed some white rope above the wire run as a visual cue.

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