[Anurag] is a computer engineering student with a knack for rollerblading. Rollerblades are not a transportation device that are often fitted with speedometers, so [Anurag] took that more as a challenge and designed this Arduino-powered computer to give him more information on his rollerblade rides.
The device uses an Arduino as the brain, and counts wheel revolutions (along with doing a little bit of math) in order to calculate the speed of the rider. The only problem with using this method is that the wheels aren’t on the ground at all times, and slow down slightly when the rider’s foot is off the ground. To make sure he gets accurate data, the Arduino uses an ultrasonic rangefinder to determine the distance to the ground and deduce when it should be taking speed measurements.
In addition to speed, the device can also calculate humidity and temperature, and could be configured to measure any number of things. It outputs its results to a small screen, but it could easily be upgraded with Bluetooth for easy data logging. If speed is truly your goal, you might want to have a look at these motorized rollerblades too.
And to think, all he needed was a GPS.
That depends. Do you want to know the skate’s speed or the skater’s?
Yeah exactly! I can measure my speed via some app like pedometer etc. But my aim is to measure the speed of my skates.
Huh? Skates are attached to the skater – correct? So measure one, you’re also measuring the other. GPS is the way to go.
What about speed skaters doing laps on an indoor track? I wouldn’t have thought GPS would be very helpful there.
10/10 This is hilariously awesome.
Thank you @Average Joe.
Cool idea, but how long could you expect the device to last with all those things dangling around?
Also, isn’t looking down a bit difficult to get the speed reading ?
I agree, it is difficult. But this a prototype and the next model will have no such problems and would be more compact as well.
I agree with you. Fast prototypes prove you can make it work. If you’re still having fun, keep pumping out revisions of the hardware until you have a hardened system that can stand up to the kind of abuse inline-skates get.
Very cool. You could use an XBee or other wireless solution and transmit the speed to a remote station for display and logging.
I like it. Makes me think of Snow Crash for some reason.
V2 should ditch the display and use addressable LED strips along the arms of your jacket that light up relative to speed. Maybe throw in a cheap ISM band RX/TX radio pair to clean up the wiring. Measure the delta of the speed to turn the strips all red to indicate that you’re stopping. Then add toe-controlled tact switches to flash the strips like a turn signal. Lots of fun to be had here.
Available commercially with wireless tx and wristwatch-style rx.
Rather than going for the ultrasound to detect if to measure speed, it may be easier to measure both skates (at least one foot is on the ground unless you’re doing lots of jumps) and then pick the highest speed of the two.
Id say pick the average, im not at all home in the physics of rollerblading, but i would assume there are moments when the wheels spin up as you push off & then lift the rollerblade into the air, causing the wheels to spin faster (then the wheels of the other rollerblade on the ground) for a short period.
A company used to make a skate speedometer. Lots of issues to sort out if you want to do it well.
I had thought of working with a small processor block (long before the Arduino or Raspberry) but the first thing would have been to do some wheel spin speed charts for both skates to check for sweet parts of the cycles to use for measurement and allow for averaging strides when they are reasonably consistent. There is also the issue of recognizing gliding time and braking time that can really mess things up if the measurement wheel is on the skate with the brake.
Another issue is recalibration as the wheel wears. One friend who used a wheel rev counter to log distance used to skate on a known distance occasionally to recalculate his conversion factor for his spread sheet.
With new technology, I just use my hiking GPS.
Haveto say that i like this old take a bit more
http://hackaday.com/2010/07/08/wear-a-helmet-rollerblades-with-attitude/
never the less always fun with people doing something