All-terrain Hoverboard Junk Pile Build

If you’re anything like us, chances are pretty good you’ve got at least one underused piece of fitness gear cluttering up your place. Rather than admit defeat on that New Year’s Resolution purchase, why not harvest the guts and build an all-terrain hoverboard for a little outdoor fun?

The fitness machine in question for [MakeItExtreme]’s build was a discarded Crazy Fit vibration platform. We’re not sure we see the fitness benefits of the original machine, but there’s no doubt it yielded plenty of goodies. The motor and drive belt look stout, and the control board eventually made it into the hoverboard too. The custom steel frame was fabricated using some of [MakeItExtreme]’s DIY tools, which is what we’re used to seeing them build — check out their sand blaster and spot welder for examples. A couple of knobby tires in the center of the board let the rider balance (there’s no gyro in this version) and power is provided by a couple of 12 volt AGM batteries. Sadly, the motor was a line voltage unit, so an inverter was needed. But it was the only part that had to be purchased, making this a pretty complete junk pile build.

See the video after the break for build details and a few test rides. Looks like it can do 20 mph or so – pretty impressive.

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Smart Sweatbands

If you’ve ever known anyone who has to monitor their blood glucose level, you know it is annoying to have to prick your finger with a lancet to draw blood for each measurement. A new sweatband that incorporates flexible electronics can measure glucose–as well as sodium, potassium, and lactate–from your sweat, without a painful pin prick.

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Physical Fitness for the Truly Lazy

We’re going to get in shape around here, starting today. Well… in the United States, it is almost Thanksgiving, so we might as well wait until… but then it is going to be the end of the year and between Christmas, Hanukkah,  and New Year’s, we should put it off until then.

OK, we get it. There’s always some excuse. We know we should go on and do some push ups today. Of course, we are a lazy bunch, so not everyone’s going to do a full push up. Then we’ll all argue how many we actually did. If this sounds like you, maybe you need an Arduino-based project that counts proper push ups.

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DIY Electrical Body Fat Analyzer

Whether you are trying to drop some fat or build some muscle, it’s important to track progress. It’s easy enough to track your weight, but weight doesn’t tell the whole story. You might be burning fat but also building muscle, which can make it appear as though you aren’t losing weight at all. A more useful number is body fat percentage. Students from Cornell have developed their own version of an electrical body fat analyzer to help track body fat percentage.

Fat free body mass contains mostly water, whereas fat contains very little water. This means that if you were to pass an electrical current through a body, the overall bioelectrical impedance will vary depending on how much fat or water there is. This isn’t a perfect system, but it can give a rough approximation in a relatively easy way.

The students’ system places an electrode on one hand and another on the opposite foot. This provides the longest electrical path possible in the human body to allow for the most accurate measurement possible. An ATMega1284P is used to generate a 50kHz square wave signal. This signal is opto-isolated for user safety. Another stage of the circuit then uses this source signal to generate a 10ua current source at 50kHz. This is passed through a human body and fed back to the microcontroller for analysis.

The voltage reading is sent to a MATLAB script via serial. The user must also enter in their weight and age. The MATLAB script uses these numbers combined with the voltage reading to estimate the body fat percentage. In order to calibrate the system, the students measured the body fat of 12 of their peers using body fat calipers. They admit that their sample size is too small. All of the sample subjects are about 21 years old and have a similar body fat percentage. This means that their system is currently very accurate for people in this range, but likely less accurate for anyone else. Continue reading “DIY Electrical Body Fat Analyzer”

Make Your Treadmill More Entertaining for $0

Treadmill Computer

Treadmills can often be found on the side of the road, after someone gave up on their running regimen and found that the machine was taking up too much space in their basement. This is great for hackers, since they have some useful parts in them.

However, if you’d like to actually use a treadmill for running, some entertainment would certainly help. [KingJackOff] decided to roll his own treadmill entertainment system out of things he had lying around, bringing the total cost to $0.

He took an old laptop and mounted it in a piece of rigid foam using a gratuitous amount of duct tape. With the screen and keyboard mounted, he added speakers and a slot for the DVD drive. Then a printed graphic was taped to the front, with a nice motivational message.

Lots of people have old laptops lying around with mechanical issues. Broken hinges and frames make them unusable, even though the electronics are fine. Some foam and paper could be all you need to bring one back to life.

[via Reddit]