Is Laser Spoke (Potentially) the Next Big Thing in Power Meters?

Ok, power lovers, imagine this: what if there was a power meter that was accurate, light weight, fit any of your wheels, you were able to switch back and forth between bikes, and was fairly inexpensive? Sounds too good to be true, right? Well, that’s exactly what Laser Spoke creator Gennady Lubarsky is envisioning with his laser based power meter. Yes, lasers.

Like many before him, Lubarsky has turned to crowd-funding with a project on Indigogo in an attempt to fund development and production of Laser Spoke. Rather than a dedicated hub, crank, bottom bracket, or pedal based power system, Laser Spoke is intended to be an add on for any wheel that allows for accurate power measurement. Lubarsky is quick to point out that the working prototype above is considerably more bulky than what he plans for the final product, which will be manufactured from injection molded plastic, rather than the aluminum housing of the prototype.

How would a laser based power meter work? More after the break.

Instead of utilizing strain gauges like a lot of the power meters on the market, Laser Spoke instead uses lasers to measure the deflection, or “wind up” of the rim in relation to the hub. Of course different wheels will have different deflections, which will mean the need for an accurate calibration for each rider and wheel set up. Lubarsky claims this is their patent pending secret weapon, in that the Laser Spoke will allow for “real time calibration by the user on the go,” allowing for accurate results. To capture the laser measurement, an optical module assembly must be attached to the rim – in this case around the valve core. The laser enters the optical module, then is relayed back to the hub where the difference is measured. To complete the power equation, the hub mounted unit will include two accelerometers to measure speed.

Of course, if everything works out and the Laser Spoke makes it to production, it has the potential to change the power market completely – but there are a lot of obstacles ahead. Namely, figuring out a truly universal mount to accommodate all of the different sized and shaped hub shells on the market. If Lubarsky finds a way to do that, as well as integrating ANT+ as he plans, and hits his weight target of 150g for the LS Pro, and his accuracy target of 1-2%, the end result will be very interesting.  You would then have the potential to use one power meter on your road bike, tri bike, fixed gear, mountain bike, or even a BMX bike without forcing you into certain wheels, cranks, or pedals.

However, the finished product seems to be a long way off, especially if the Indiegogo project is any indication. Of his $85,000 goal, backers have only pledged $631 with another 34 days left. For more information on the project, jump on Laser Spoke’s site here.

Comments

Mark Ifi - 05/22/12 - 6:41am

I think it’s a fantastic idea, badly executed.

- I hate the fact that he didn’t bother putting a counterweight opposite the valve to balance his wheel.
- Clearly, the asking price is way too high for such simple electronics. it’s almost in powertap territory.
- without proper integration in the rim the reflector part on the valve can move during a crash or accidental offroad section, messing up your data on that all important race.
- therefore should have been seeking for partnership with mavic or shimano, make less profit per unit in the process, but sell more units.

I love the gopro images though.

sam - 05/22/12 - 8:19am

This looks really sweet! I have not yet been able to justify buying a power measurement device, but this looks like it might fit the bill.

dave - 05/22/12 - 8:21am

neat idea, polar had a similar product using chain deformation…setup was VERY tricky.

something like this could actually work assuming you had some kind of machine to calibrate each wheel AND you had some kind of mount for each bike that gave you a precise, repeatable mount point.

Dr. Evil - 05/22/12 - 9:16am

“You know, I have one simple request and that is to have sharks with frickin laser beams attached to their heads.”

Chris - 05/22/12 - 9:36am

So the laser reflects off a shiny surface on the rim? Ok, I’ll bite.

What happens when you are riding in the rain? dirty/salty roads in the winter? mud on a mtb/cyclocross bike? Even dust from a dry dirt road or trail is enough to obscure the finish of a rim. Is this application only intended for indoor use? Ergomo tried using reflective light for a power meter in their ‘optical strain guage’… we saw what happened to them.

Josh - 05/22/12 - 10:41am

I like the fact that he’s trying to think outside the box and avoid strain gauges. The issue I see here is that wind-up is dependent on spoke tension. Every time you tension your spokes you’d have to re-calibrate. It also looks like the system measures circumferential or tangential wind-up and ignores lateral loading which will affect the wind-up. If you’re pedaling through a corner the lateral forces will increase spoke tension and decrease wind-up.

Psi - 05/22/12 - 5:18pm

Ergomo’s failure doesn’t tell you anything about how well optical sensors can be applied to power measurement. Instruments like this are used a lot to measure angular displacement, and they can measure very small displacements, on the order of micro radians or better (5/100,000° or so). This is a bad application, though. Water droplets, dust, and other particles could very well cause enough beam deviation to introduce significant noise (uncertainty) or error in the measurement. Bumpy roads could very well do the same. Also, while it would be easy enough to get a measurement that gives something like relative power, it’s not obvious how Lubarsky will derive absolute power. Also, as someone else mentioned, changes in spoke tension and/or wheel trueness will cause changes in the measurement.

richard - 05/22/12 - 5:28pm

when in the rain it may change the angle but it may not be enough to change anything within the specified error. as for the corners you could probably use a curved mirror and it would always focus at a certain point. then the corners would not be an issue. and i am not sure but he is measuring deflection. and then the mounting would not matter. and as for a counter weight that is ridiculousness, are you really going to notice? and he has not posted a price.

Billy - 05/22/12 - 6:41pm

umm… if the only company to ever use optical sensors has tanked …twice… I think its a fair statement that their (optical sensors) design application for power measurement on bicycles (outdoors) is lacking. Having any open air beam of light is subject to the elements (dust, moisture) and the introduction of noise (error) into the power equation. (Not to mention the reflective surface) But I guess if they are cheap and inaccurate, then bring it on! I say this to mean, MetriGear wasn’t even a company with a product sold at retail, yet another company saw the potential and bought them (Garmin) – If optical strain gauges are worth their mettle, another company or silicone valley start-up would have done it by now. ….Pedal based power meters are a completely different topic!

khai - 05/23/12 - 9:18am

Will only work on indoor trainers an maybe the velodrome.

Gennady - 06/01/12 - 6:52am

We have some great news to share! I’m happy to announce that Laser Spoke ltd has applied for an Invest Northern Ireland grant (£50K) to run research and development on this project.

We have reviewed carefully our budget taking into account this serious government support and success of our IndieGoGo campaign. We are able now to introduce new prices for our perks for the period of this campaign.

We want to invite even more people to our project. Please share this great news with your friends, cycling clubs and welcome.

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