RepRap Acrylic Extrusion Using Hotbed

January 5, 2010 by Mike Szczys 16 Comments

[Nophead] started the year off by successfully extruding acrylic using a RepRap machine. The problem when working with this material is that when the hot ooze hits the cold air the printed material tends to warp, badly. [Nophead] raised the ambient air temperature around the part being extruded by replacing the bed of the RepRap machine with a heated aluminum plate.

We took at look at his build details for the hotbed. The plate itself is aluminum that he had milled by a machinist friend of his. It looks like the heat is produced by a network of power resistors bolted and soldered to the bottom of the plate. The original idea was to produce a controllable SMT soldering platform. Unfortunately this heating method doesn’t have the power needed to raise the temp quickly but that failure turned out to be a RepRap success.

Generate Electricity With A Candle

January 5, 2010 by Mike Szczys 67 Comments

What you see above is a generator that converts heat to electricity. [Reukpower’s] thermoelectric lamp is one of those hacks that makes you scratch your head even though you understand why it should work. The heart of the system uses a Peltier cool, just like the thermoelectric solar generator. When there is a temperature differential from one side of the Peltier to the other a small current is generated.

In this case a candle heats one side and a heat sink cools the other. The tiny voltage picked up from the Peltier’s contacts is then boosted using a joule thief. We’ve seen LEDs powered with a joule thief before, benefiting from their own low power consumption. In this case, the boost circuit is scavenged from an emergency phone charger and probably achieves higher efficiency than if he had built it himself.

Record Player Display Sans POV

January 5, 2010 by Mike Szczys 32 Comments

At first glance we thought this record player had been modified to serve as a persistence of vision device. The device looks very much like an unmodified turntable but it has four tracks worth of display space in it. The messages are actually glowing and don’t depend on a POV effect. Instead, the table has been coated with phosphorescent paint that will glow after being exposed to bright light. The needle has been replaced by a small PCB with downward facing LEDs on it. A microcontroller pulses the lights to expose the paint in patterns that make up the messages. This is the same concept we saw with the Ghost Matrix but this iteration is silent, and the control circuitry is less apparent.

The video after the break is a must-watch. The 60 character long messages are beautiful to watch rotate into the display. Unlike a POV display, ambient light will greatly interfere with the effectiveness of this method. That being said, what a wonderful party decoration this would be if mounted on a wall in a rather dark room.

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Missile Hack Taunts Your Cat

January 5, 2010 by Mike Szczys 8 Comments

[youtube=http://www.youtube.com/watch?v=3K7rTWnuQ6Y]

[Atlantageek] sent in a missile launcher project that he threw together. For Christmas he received a Chumby One and a ThinkGeek USB Rocket Launcher as gifts (lucky dog). Neither of these toys are “played with” in the traditional sense as much as they become centerpieces of your next hack. In that spirit, [Atlantageek] immediately wrote a widget to control the launcher via the Chumby. The side effect of driving his cat bonkers was an unexpected bonus.

Arduino Traffic Light

January 5, 2010 by Mike Szczys 28 Comments

[Rockwell] sent us an update on his traffic light hacking. Dedicated readers will remember seeing this legally attained traffic signal controlled through a parallel port from back in 2005. The new update swaps the old port for USB and adds several autonomous functions which are demonstrated in the clip after the break. The update includes a nice UI and some notifications for things like email, IMs, Reddit posts, etc.

He’s given control of the hardware over to an Arduino. Instead of building the board into the project he’s included just the parts he needs; an AVR running the Arduino bootloader, a crystal and filtering caps, and an Arduino serial to USB module for connectivity. The AC load switching is handled by three relays. The relays he links to are 12VCD rated coils. We think this should have pointed to 5VDC coils as that’s the voltage that the logic circuit are running at. Be careful with switching these AC loads, this traffic light isn’t a toy.

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360 Degree Video For Next-to-nothing

January 4, 2010 by Mike Szczys 50 Comments

[Luis], a regular Hackaday reader, sent in some info about his 360 degree video experiments. He wanted a cheap device to use with a video camera, producing video that can be displayed using a free Flash software library.

The hardware consists of a mirrored light bulb, a square of glass, and some threaded rod. The camera lens attaches to the glass with the rod right in the middle. The lens will capture a donut image reflected in the mirror of the bulb. [Luis] then processes the result and uses Ryubin’s Flash Panorama to handle playback. He’s posted two clips as examples, the first of an “Existentialist Suburb Walker” and the second is some test footage while setting up for a shot. You can click-and-rotate the video while it’s playing to look around the area.

This could produce some great driving videos, without the need for multiple cameras. [Luis] does point out some problems with oscillation as the mirror on the end of a rod will amplify the effect of movement on the image.

Double Clutch Transmission Model

January 4, 2010 by Mike Szczys 44 Comments

[Alan] did an extraordinary job building a computer controlled model gearbox. His project from several years back is based on a dual-clutch Direct Shift Gearbox that was developed for VW and Audi vehicles. His design uses a gear head motor to provide the locomotion to this transmission. Shifting is computer controlled through serial cable, with servo motors providing the physical motion to change gears. Seeing all these moving parts in the clip after the break might make you a bit dizzy.

This is some extreme model building. It reminds us of the guy who built that aluminum aircraft model that was all over the Internets in December.

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