August 15th 2012, the news was reported that [Hanz Camenzind], the creator of the 555 timer, has passed away. We are all familiar with 555 timer, but many of you may not be aware that [Hanz] also created the first class D amplifier. Actually, he had over 20 patents under his belt as well as a few books.
He is survived by His Wife, Daughter, and three Sons.
Several weeks ago, I was in Culver City L.A., and happened to find a hackerspace nearby. It was a pleasant coincidence that the night I chose to randomly show up, was their public meeting which focused more on projects people were doing. The place was packed, I was barely able to squeeze in the door and actually stood outside for part of the meeting, just listening to people talk about what they’re making.
One of the projects I did get to see was this bike helmet built by [Naim]. At first I was amused at the idea, but the idea of putting lights and an accelerometer on a helmet wasn’t that groundbreaking. But as [Naim] kept talking, he caught my attention. For one thing, the one he was showing at the hackerspace seemed to have some built in correction for natural head movement. In this video he does look around a bit without false positives. At the hackerspace he explained the way he monitors the motion to avoid natural movements causing the lights to initialize.
The part I was really interested in was his power. He spent tons of time reducing the power consumption on the base arduino. I believe the number he used was 10 years of standby without causing the battery to vent or die. If you pick up the helmet at any point during that time period, it automatically turns itself on based on the accelerometer’s motion. While the bike helmet itself was a fairly cute idea, I was really trying to get him to send me the information on how he’s saving power. I believe he had to cut the traces to the arduino’s native power management. Hopefully we’ll still hear from him on the details.
Those of us living in the first world take clean clothes for granted. Throw them in the washing machine, transfer to the dryer after 45 minutes, and you won’t smell for another two weeks or so. But for people living in areas without electricity, clean clothes are a huge amount of work. Hand washing a family’s clothes is estimated at 6 hours per day, three to five days per week. Here’s a post that looks at some of the different human-powered washing machines out there.
We’ve built our own human-powered machine before using a five-gallon bucket with a hole in the lit to receive the handle of a toilet plunger which acts as an agitator. But that pales in comparison to some of the machines seen here. The concept we like the most is shown above. It’s an MIT project being used at an orphanage in Peru. The bicycle lets you easily power the spinning basket inside of the drum. The rear derailleur has been mounted on the axle so that the rider has a wider range of gears when spinning heavy loads. Take a look at the post linked above to see all of the offering, but we’ve also embedded video of two of them after the break.
If you were looking for a washing-machine powered bike instead of a bike-powered washing machine you’ll want to head on over to this post.
Continue reading “Washing Machines That Do It Without Electricity”
We’ve got something of a love affair going on with quadcopters, but there’s still room for a little something on the side. This fixed-wing drone can pull off some pretty amazing navigation. MIT’s Robust Robotics Group is showing off the work they’ve done with the plane, culminating in a death-defying flight through a parking garage (video after the break). This may not sound like a huge accomplishment, but consider that the wingspan is over two meters and repeated runs at the same circuit brought it within centimeters of clipping support columns.
Unlike the precision quadcopters which depend on stationary high-speed cameras for feedback, this drone is self-contained. It does depend on starting out with a map of its environment, using this in conjunction with a laser rangefinder and inertial sensors to plot its route and adjust as necessary. We think the thing must have to plan a lot further ahead than a quadcopter since it lacks the ability to put on the brakes and hover. This is, however, one of the strengths of the design. Since it uses a fixed-wing approach it can stay in air much longer than a quadcopter with the same battery capacity.
Continue reading “Autonomous Fixed-wing Drone Threads The Needled In A Parking Garage”
This is a Raspberry Pi outfitted in a DSLR battery grip. [Dave H] was very interested in the idea of combining a single-board computer with a high-end camera. The size and cost of such a computer was prohibitive until the RPi came along. He managed to fit the board into the broken battery grip he had on hand, and he already has the prototype up and running.
[Dave’s] alterations to the battery grip allow access to the USB, Ethernet, and Composite video ports. Powering the RPi was a bit of a challenge. He tried using an iPhone charger with four AA batteries but that only provided 4.2V. After going back to the drawing board he discovered he could rework the parts that he removed from the grip, using a Cannon 7.2V 1800 mAh battery. So far he can automatically pull images from the Camera and transmit them over a network connection. But since the RPi is running Linux, there’s a whole world of hacks just waiting to be exploited. What comes to mind first is image manipulation software (like ImageMagick) which has a command-line interface.
[Thanks Christian]
[Rob] has been hard at work designing and building this LED suit which he can wear to parties. He’s got it working, although right now it’s just a pair of pants. It reacts to sound, and has the potential to be controlled from a smartphone via Bluetooth. You’ll find a video description of the build embedded after the break.
The planning started off by selecting driver hardware for the LEDs. [Rob] wanted the suit to pulse to the music in the room so he grabbed an MSGEQ7 chip. When connected to a microphone and opamp this chip will output a signal which can be used as a VU meter. He built the hardware into an Arduino shield, then got to work on the LED driver board. He’s using LED strips, but they’re not individually addressable. Instead he cut loops which wrap around the wearer’s legs. Each loop connects the pins of a TLC5947 LED driver chip which sinks a constant current and offers PWM abilities. He’s using PNP transistors on the high side.
For anyone that’s ever worked in a Tyvek suit before you’ll know they don’t breathe. Sweat will literally be pouring off of you. And we’d bet that’s what cause the short that burned the back of [Rob’s] leg at a recent party. Then again, your light-up pimp coats are going to be hot to wear too.
This is a Gemei G9T, a 9.7″ Tablet running Android 4.0. [Carnivore] shows us how to modify it to use inductive charging. The inductive charging hardware is taken from a Palm device (this uses the Touchstone charging hardware seen in several other hacks). It’s easy to interface with the tablet’s electronics, but physically placing the coil and magnets is another story.
The video after the break gives you a full walk-through of the process. He starts by removing the screws and prying the case off of the tablet. From there [Carnivore] shows how to carefully remove the coil, circuit board, shielding, and magnets from a Palm back plate. The magnets are the first to be positioned on the tablet’s back plate. The metal is too thick for them to hold well so he uses a Dremel to grind away just enough material for a strong connection. Unfortunately the metal will shield the magnetic fields the coil needs to work so he cuts a hole in the case the same size as that coil. The area is covered in liquid electrical tape to prevent shorts, and everything is taped in place. Two jumper wires connected from the coil’s circuit board to the 5V charging input are all it takes to finish up the hack.
Continue reading “Adding Inductive Charging To An Android Tablet”
