Inline Skates LED Brake Light


I'm planning to build LED brake lights for my inline skates. The main problem I've encountered is how to detect braking because while skating you don't press any pedal or lever to brake: you slide your wheels against the pavement to reduce speed.

I've thought about using an accelerometer but discarded it because of the price and due to my poor coding abilities. I'm currently thinking about using a tachometer (RPM sensor) approach.

[u]Which method do you recommend?[/u]

1.- IR break-beam. Pros: Cheap, does not modify the wheels. Cons: Outdoor use might not allow precise readings 2.- Hall Effect sensor Pros: solid state, code availability Cons: requires adding magnets to the wheels 3.- Reed Switch Pros: easy coding Cons: reliability, fragility, installing magnets

Requirements: - Lightweight - Extremely shock-resistant - Small sized (it will be mounted below the boot in a small space above the wheels )

Thank you in advance!!!

P.S. I'm quite a begginer in electronics and Arduino programming. I own an Arduino Uno but I'm planning to use ATtiny or ATMega for this project.

simplest approach is to have a switch in your hand elbow arm or wherever . A nice one could be switched in your fingers (flex sensor) as when you brake you make a fist or so different angles (of different fingers) could be used to control far more than just the breakllight (e.g. mp3 player)

for RPM -> hall effect ,

but I recall that the wheels of the skate continuously go faster lower faster slower at every push... think a reliable detection algorithm can be difficult

Mont a switch in your wrist protectors. If you press your palm (or hit the floor) the light go on. Better put the lights on ypur vest, because on your skates they might be to low for drivers to notice.

Thank you for your quick replies!

Utilising a push button will be my last resort option. I want to experiment with RPM readings and have automated light ;)

About the problem of wheels going faster/ slower with each stride I guess I will have to set a very large decrement in RPMs between readings to activate the LEDs and thus differentiate braking from regular deceleration.

The Hall Effect sensor will be the one I'll start experimenting with. I appreciate the recommendation.

As far as I can figure it from watching these things on YouTube, braking with these things consists of turning the skates sideways to force a slide. Without any way to sense when sliding occurs, I don’t see any way to differentiate between hard cornering and braking.

Just maybe you could use an optical mouse mounted under the boot and use flow detection to work out which way the road surface was moving?