• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Motion sensitive switch for light

Status
Not open for further replies.

piesoup

New Member
Hello

As this is my first post I'll introduce myself. I am an Aircraft Technician in the Army and am involved in the mech side of life. However I have a basic understanding of electrics and electronic circuits. ie. Ohm's Law, power etc. I design and build high power LED bicycle lights using CREE LEDs. This is the forum we usually hang out in Lights DIY - Mtbr.com Forums


As you will know, these LEDs, when driven at their upper limit require a great deal of heatsinking to keep them cool. I use the air rushing over the aluminium casing to keep them cool. However, when we stop riding we have to remember to turn the light down or off so it doesnt overheat. If it isnt turned down that isnt a problem for the LEDs as the constant current driver that I use has a temp sensing function and will dim the lights when they hit the preset temp. Usually 50 degrees C. Now that presents problem as it will only allow the light to retuen to max when the temp has dropped by 5 degrees.

Now for my idea! I want some electronic wizardary to sense when the bike has stopped and dim or turn off the light. ANd then turn it on again as soon as the bike starts to move.
I have thought about using the wired sensor that cycle computers use to measure wheel speed. A simple magnet on the wheel spoke to a switch.

The driver utilises a single momentary NO switch to turn on and off and cycle between modes. Here it is Tasklight
All the *.flex drivers use the same UI. In short, a single click ( < 0.3 sec ) turns On and a press > 4 sec will turn it off from any level. (It will cycle from level 5 down to level 1 then 2 sec later turn off.)

So, is there something I can build to put in parallel with the existing switch to give me auto off and on? Like a micro controller of sorts?

I have tried to search but there is nothing to be found. Could kind person help out and point me in the right direction!

Thank you for reading this far, I hope it all makes sense!

Andrew
 

piesoup

New Member
Bump
This had to be approved by a mod so just bringing it to the top of the list.

Thanks
 
Last edited:

piesoup

New Member
If I havent described it well enough please let mo know. Maybe someone has done something similar in the past?
All I need is a circuit that when it stops receiving a signal from the front wheel, it latches a switch for 4 seconds, turning off the light. Then when it receives a signal from the front wheel that the bike is moving again, the switch is latched for 0.3 sec, turning my light on again. Anything out there that can do this?

Thanks
 
Status
Not open for further replies.

Latest threads

EE World Online Articles

Loading
Top