Quick Keyboard Hack to Control Heavy Loads

When you want to control an external device (like a lamp) from your computer, you might reach for a USB enabled micro. Looking for an inexpensive and quick option to control two lamps [Pete] wanted to control a couple 12 volt halogen lamps, he reached for his keyboard and used a little bit of python.

Desktop PC keyboards have 3 LED’s indicating lock functions, hardly anyone uses the scroll lock, and on a laptop with no keypad, numlock is no big loss as well. Adding wires to the little PCB out of a USB keyboard the numlock and scroll lock LED’s 5 volt output was redirected to a switching circuit.

That switching circuit takes the output of either LED, inverts it with a PNP transistor, then connects to the gate of a FQP30N06L, “logic level” mosfet transistor to handle the heavy lifting. Once the wiring is in place a fairly simple Python script can take over turning on and off the two chosen lock keys, giving  control of up to 32 amps with the touch of a button.

Retro Games on ArduinoCade Just Shouldn’t Be Possible

Making retro video games on today’s micro controllers brings many challenges, especially when using only the micro controller itself to handle the entire experience. Complex graphics, sound, game logic and input is taxing enough on the small chips, toss in NTSC color graphics and you have a whole different bear on your hands.

[rossum] set out making the Arduinocade retro game system using an overclocked Arduino Uno, and not much more. Supporting 4 voice sound and IR game controllers, the system also boasts 27 simultaneous colors all in software. These colors and the resolution feel like they’re impossible without a graphics chip to offload some of the work. While doing all of this the ATmega328p is also playing some faithful reproductions of classic arcade games.

The uses a couple of interesting tricks. Color is generated with NTSC color artifacts, where the screen is really black and white, but thanks to a delay or two in the signal generation the bits are out of phase from the reference “color burst” signal and appear on-screen as unique colors. This approach was used in the 8 bit Apple II personal computers to generate its colors, and also on the early IBM PC’s with CGA cards to drastically increase color depth. In this case, the chip is overclocked with a 28.6363 MHz crystal (a multiple of NTSC timing) and the SPI hardware leveraged to shift out all the necessary pixels. Check out how great it looks and sounds after the break.

It’s good to see an old trick on a new project and we are off to play some games!

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Laptop Broken? Get A Bigger Hammer

The weakest point in a laptop case may be the screen hinges, especially in heavily used machines. The mechanical stresses involved with opening a laptop can often break the thin plastic screw bosses and cause the threaded insert to pop out. What do you do? Get a hammer and some tacks of course!

[mightysinetheta]’s solution involves popping the bezel off the offending screen, then aligning the hinges in preparation for drilling holes though the computer’s plastic lid. Then he placed some short tacks though the holes and the hinges. Pressing the hinge down into the lid to ensure a tight fit, the hammer comes out to peen over the tip of the nail. Course that can be time consuming so just bending the tack over and flattening it down with the hammer works just as well.

With the hinge secured back into place his trusty laptop is back in service. The new additions on the back of the lid add a bit of a custom look that is purely functional.

While you’re in there… might want to replace that charging port that’s been wiggling mysteriously.

Hack Puts Aging Sprinkler System Online

Water conservation is on a lot of people’s mind, and with an older sprinkler system one may not have the finest control of when and where the lawn is getting its water. Faced with such a system [Felix] decided to hack into his, adding better computerized scheduling, and internet remote control.

The brains of the operation is handled by a Moteino, which is a Arduino compatible micro controller board with WiFi on board. In order to interface with the sprinkler system, an interface PCB is made. The interface has an on board buck power supply to regulate the 24 volt AC power of the sprinkler down to 5 volt DC for the micro and the 74HC595 shift registers.

The output from the shift registers connects to a pin header where the stock computer normally would have plugged in. With a little software and a phone app, the new micro-controller takes over the sprinkler’s TRIAC’s turning on and off zones with a push of the thumb.

Join us after the break for a quick demonstration video.

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Mini Fridge turned Gameboy Puts Hot Games on Ice

The plain old white mini fridge, a staple of many dorm rooms could use a little decoration. The resemblance to a classic gameboy is not that hard to imagine with some novelty stickers, but [ModPurist] went the extra mile with his Cold Boy.

1514387thumbMaking a mini fridge into a playable gameboy involves taking apart the door, once in a Raspberry Pi 2 is fitted in along with a second hand “square screen” LCD. The front of the door is cut for some custom wooden buttons, which are connected to tactile switches. Once everything is fit and finished the door is reassembled, so the fridge can resume its normal life keeping soda and hot dogs good and cold. [ModPurist] covered the progression of the hack in his work log.

While it’s a little low to the ground, it should be a hit at college parties where being on the floor is not unusual. Join us after  the break for a demonstration video and get your game on. It is, of course, missing one thing. There needs to be some type of latch inside to secure the beverages until the Konami code is entered.

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Building a Better Mousetrap With The Raspberry Pi

Build a better mousetrap, and the world will beat a path to your door, but what about a smarter mousetrap? [Alain] decided to find out by making a Raspberry Pi-powered, Internet-connected smart trap. The brains of the operation is a Pi running Arch Linux. Connected to that is a IR trigger, a servo to unlatch the sliding door, and a camera to see your new friend.

The housing of the trap is CNC cut foam PVC board, which is both easy to cut and to clean. Once the IR beam is broken the Pi turns the servo, which pulls a pin on the front door. Once your new friend is settled in a LED light turns on to illuminate the subject, a picture is taken and sent via email.

With automated alerts you don’t have to manually check the trap, and you also don’t have to worry about a trapped animal being inside for too long. Join us after the break for a demonstration video showing off all the features, and a real world example.

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3D Printed Mini Vectrex

With the more common availability of 3D printers, making miniature models of retro computer and video game gear is one way to nerd out and not fill the house up. [Jason] was looking around and noticed that no one has modeled the Vectrex video game system and stepped right in to fill the void with a working 3d printed miniature model of the unique early 80’s video game system.

For those who don’t live and breathe retro game systems, the Vectrex is a 1982 8 bit game machine unique in the fact that it comes with its own monochrome vector graphics CRT in the console. [Jasons] model features a 2.2 inch LCD with a SPI interface.

Emulation is powered by a VoCore SBC sporting a 360Mhz MIPS CPU and a modest 32 megs of ram, which is more than enough to handle the 8 bit math and wireframe graphics. The emulator used is a port 0f VECX with the display rerouted to the LCD screen instead of using standard SDL interfaces.

The case was modeled in Sketchup, and the whole lot is powered by a 3v3 lipo battery.  Join us after the break for a quick video of the mini model running the introduction to “Mine Storm” which was the onboard game original to the machine.

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