LEGO automatic transmissions

[AviatorBJP] is building some impressive automatic transmissions using LEGO parts. Your best bet is to check out his YouTube channel as he’s got a slew of videos related to topic. We’ve embedded test footage of first and second generation vehicles as well as the most recent flywheel design after the break. But we’re getting ahead of ourselves, let’s look at how the system works.

Each transmission centers on a mechanism that includes hinged arms attached to a central axle. The arms are held together with a rubber band but as the axle spins faster, they overcome the elastic force of the band and begin to pivot outward. This pulls the shaft in one direction, moving its gear up to the next position in the transmission box. To test the system [AviatorBJP] uses a treadmill. A string is attached to the front of the vehicle to keep it in place and the treadmill is switched on to simulate engine power.

This design is quite brilliant, and he’s not keeping it to himself. If you’ve grown tired of the manual LEGO transmission you built, you can follow his multi-video build process to make one of these for yourself.

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Airsoft minigun packs quite a punch

[Kuba_T1000] built a multi-barrell Airsoft minigun with an unbelievable firing rate and an almost inexhaustible ammo pack. The gun is made entirely from aluminum which meant some time on the CNC machine. The six barrels don’t rotate but they are all used, resulting in the carnage shown in the video after the break. That large box you see is the ammo pack, which can hold 16,000 BBs and uses an electric feed system to reach the necessary delivery speeds. It is certainly not something you’d want to run into as part of an automated turret.

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Automated car cover

[Mike] covers his car whenever he puts it into the garage because the top is always open. After years of this ritual he decided to upgrade his garage to automatically cover the vehicle. The car cover, made from a few bed sheets, attaches to the bottom of the garage door. At the front of the stall the cover has two half-pound weights sewn in with plenty of padding to protect the car’s finish. Ropes attach to these weights, travel through a pulley system, and connect to the garage door opener carriage. This $65 dollar solution makes sure [Mike’s] car is always taken care of.

[Thanks 02TA]

Fully-automatic crossbow

We received an excited email from [Noah] regarding a gentleman who works with crossbows and crossbow pistols. Begrudgingly, we took a look and what we saw made our day. [TheDuckman666] must have an insatiable love for all things crossbow. His webpage has details and pictures covering seven different models that he built. His YouTube channel shows off three more models, all with magazines for multiple bolts.

Seeing the electrically-cocked, automatic projectile launchers wets our appetite, but we do wish there was more background info about the build process.

Automatic pneumatic drum kit

Move over Steve and PEART… there’s yet another robotic drummer in town. [Fauzii] tipped us off to his own MIDI-controlled creation – WizardFingers. According to him, WizardFingers is already capable of 64th note rolls at over 250 beats per minute. That’s on every drum simultaneously. Each drum is hit with a lever attached to a linear pneumatic actuator. A laptop running MAX/MSP generates MIDI sequences, which are sent to Doepfer MTC64 board. All of these actuators are hooked up to the board, which sets them off in sequence.

[Fauzii] ultimately hopes to develop AI software that will allow WizardFingers to compose its own tunes on not only a drum kit, but bar chimes and an organ as well. His site documents the whole concept quite well (just watch out for wild cats).

Automatic JTAG Pinout Detection

Figuring out the JTAG pinout on a device turns out to be the most time consuming hardware portion of many hacks. [hunz] started a project called JTAG Finder to automatically detect the JTAG pinouts on arbitrary devices using an 8bit AVR ATmega16/32L microcontroller. Check out the slides (PDF) from the talk as they break down how one finds JTAG ports on an arbitrary device, with or without a pinout detection tool. [hunz] is looking for people to pick up the project where he left off.

Once you determine the correct pinout, you will need a JTAG cable: there are two main types, buffered and unbuffered, both of which I have soldered up and tested from these circuit diagrams (image of completed buffered cable here). The software most hardware people use today are the openwince JTAG Tools. To get the JTAG Tools to compile, grab the latest source directly from their CVS repository.

The last time we featured JTAG was with regards to Linksys devices, but the tools listed above can be applied to any device with JTAG.