Kensboats7 Posted October 20, 2016 Share Posted October 20, 2016 A biker admired the car yesterday and in course of conversation mentioned a new type of LED inertia brake light, which operates when the brakes are applied but is not actually connected to the brake system. Anybody heard of this? It seems these are easy to fit and are completely self contained, ie they can also be battery operated or taken straight off of the battery. He did not have much information, but did say he had seen them in use and they apparently work fine, even when worn by the rider! Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 20, 2016 Member Share Posted October 20, 2016 Didn't know they existed, but it has been suggested that the deceleration from the massive drag is so high that something like that would help. And accelerometers are very cheap now because of smart 'phones. Sounds good.Would it be better to drive the existing brake lights?Review of the Ohmics light system.JonathanPS: My touring human powered bike now has something similar: the rear light flashes when the bike decelerates. But it isn't driven by the deceleration... Link to comment Share on other sites More sharing options...
Kensboats7 Posted October 20, 2016 Author Share Posted October 20, 2016 Just struck me that this could be easily fixed either to the roll bar, or maybe even the roof itself or other conveinient place without the bother of permanent wiring. Are they legal is another question too. Link to comment Share on other sites More sharing options...
Stridey Posted October 20, 2016 Share Posted October 20, 2016 Without wanting to sound stupid... How does an inertia switch differentiate between inertia and the car being at an angle on a hill? Link to comment Share on other sites More sharing options...
SM25T Posted October 20, 2016 Share Posted October 20, 2016 Would need to be used in conjunction with regular brake lights. Wouldn't pass MOT on its own as it won't work when car is stationary. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 20, 2016 Member Share Posted October 20, 2016 Without wanting to sound stupid... How does an inertia switch differentiate between inertia and the car being at an angle on a hill? You're not.Jonathan Link to comment Share on other sites More sharing options...
Stridey Posted October 20, 2016 Share Posted October 20, 2016 Phew! Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 20, 2016 Member Share Posted October 20, 2016 Look what happened once Uncle Albert asked questions like that...I'm guessing, but the answer may be that they have gyroscopes as well as accelerometers.Jonathan Link to comment Share on other sites More sharing options...
Drumster Posted October 20, 2016 Share Posted October 20, 2016 7s with lightened flywheels can decelerate fairly promptly without the need for braking, so this could be useful, but more it will be a nuisance because if the inertia switch is sensitive enough every time you lift off the brake lights wil come on. It's bad enough having to follow 'comfort' brakers as it is.... Link to comment Share on other sites More sharing options...
john milner Posted October 20, 2016 Share Posted October 20, 2016 Going down a small local hill in the 7 I need to touch the accelerator or I will slow down. The same hill in my tin top needs braking to maintain a sensible speed. In principle an inertia brake light sounds like a good idea for a lightweight un-aerodynamic vehicle but I am dubious that one could be set-up accurately or of it's legality. Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 20, 2016 Member Share Posted October 20, 2016 The Road Vehicles Lighting Regulations 1989, but it's not always easy to be sure it's current.I'd think of the legality in two parts: The lights. If you pass the deceleration signal to the existing legal lights there's no issue. If you use additional lights they'd have to comply. The manner of activation. I can't see a problem with the Regulations... except that if you use additional lights and classify them as stop lights you'd have problems with 10 a ii.Jonathan Link to comment Share on other sites More sharing options...
Leadership Team 700newtons Posted October 20, 2016 Leadership Team Share Posted October 20, 2016 Without wanting to sound stupid... How does an inertia switch differentiate between inertia and the car being at an angle on a hill? You're not.I think you could get around this problem by having two accelerometers at 90 degrees (one vertical and one horizontal). Link to comment Share on other sites More sharing options...
OliverSedlacek Posted October 20, 2016 Share Posted October 20, 2016 The accelerometers in smart phones sense all three axes and include three axis gyroscopes. That means the microprocessor has access to all the information it needs to estimate deceleration. I don't know what deceleration trip point you would set, but 0.2G would be my starting point. Link to comment Share on other sites More sharing options...
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