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Hooking up LEDs to Switches

VoltageNoob

Jun 28, 2015
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So I want to put switches on the handlebars of my bike, and have them connected to some LEDs that I plant to throw onto the back of my bike rack.

I know I need a good length of wire, two rocker switches, the LEDs and a battery holder.

What else do I need? Will I need a board or anything else if I want them to flash?

Thanks!
 

Martaine2005

May 12, 2015
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Hi, sounds like a good project. I used to do the same with CB radios and xmas lights on mine.

What exactly do you want to achieve?
Brake lights? turn indicators? Just lights?

You will need other items like resistors, capacitors and transistors if you want them to flash.
What led's are you going to use? Singles or strip?
Can you draw a diagram of what idea you have?

Martin
 

VoltageNoob

Jun 28, 2015
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Hey Martin,

I love the CB radio idea - that's terrific.

Just think very basic - Literally just two signal lights, one on either side of the back of my bike. I thought it would be a fun do-it-myself project that would have something interesting by the time I'm done and that I could learn something while I'm at it. I'm currently just finished reading the "How LED's Work" section from the resources page (https://www.electronicspoint.com/resources/got-a-question-about-driving-leds.5/) - Interesting to think about the power supply as a current source - that's going to make things much more difficult than I expected. Already learning!
 

Martaine2005

May 12, 2015
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Not at all. Just two simple fashers from A pp3 battery.
It could be done even easier with a flashing led! But where is the fun in that?
Can you read a simple circuit diagram? I can do one for you if you want.
Martin
 

VoltageNoob

Jun 28, 2015
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I think I can. I have managed to retain most of the electronics stuff I took in high school, and I've been dabbling for years. Thanks for the offer, I don't know if I could draw one myself since I don't know what I'd need.

I've noticed that there are a few flashing LEDs that have resistors built-in - but you're right, where's the fun in that? I imagine they'll have to be pretty bright for the application - my bicycle headlamp is a cluster of LEDs at 1Watt, but I don't know how many lumens that is. And I suppose a 9V pp3 is fine, but I could switch out the holder for a 9V in 4 AA batteries too, right? I can recharge them.
 

Martaine2005

May 12, 2015
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You could yes.
But the voltage will be diffent. Nimhs will also be a lower voltage than Alkaline too. 1.2v vs 1.5v.
So 4.8v rechargeables or 6v alkaline. Or 9v pp3.
So what led do you want to use? Back of a bike is usually RED. But indicators are usually AMBER.

Martin
 

VoltageNoob

Jun 28, 2015
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Good point - I guess four 1.5V AA batteries in series would only add up to 6V - still doable?

I was thinking red, even though you're right that Amber is generally signal colour - I was also considering a box/cover for the LEDs to protect them from rain/etc and it could have a filter so the LEDs could all be white?
 

Martaine2005

May 12, 2015
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You may be better getting a small sealed lead acid battery. They deliver more amperage per hour and are still rechargeable.
The white led's do have a higher forward voltage to operate.
Let me have a play later after dinner.
You also only need one switch too.

Martin
 

VoltageNoob

Jun 28, 2015
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Well I wanted the switch on the right to run the right signal, and the one on the left for the left signal. I was looking at the batteries you mentioned too, they seem to come in 6V and 12V varieties
 

Martaine2005

May 12, 2015
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Hi and sorry for not responding.
I had to babysit my nephews at a moments notice.

The switch can be a single switch like a motorcycle indicator switch. Flick it 'left' back to centre or flick it 'right'.
I have done quite a few diagrams for you on paper, but need my LTspice diagrams checked by a good friend first. (they don't work):( . I am new to software design, I usually play on breadboards.
But I have found some great sites (youtube on sisters TV) like this chap. here
And another here. Sorry, I can't find it because it's in my sisters history. Not mine.
Don't worry though. We will make you look like chritmas tree on steroids!!
I did have a thought though! would you like to go a little more Techno?
With some really cheap ic's you can rock 'n' roll on your bike. (555 timer)?

Martin
 

Gryd3

Jun 25, 2014
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Go to a wrecker and find a Turn indicator switch from an old motorcycle.
They are mounted on the left handlebar, and the switch is a double throw switch with an off location in the middle... here's the catch. Flick it left to enable the left lights, flick it right to enable the right lights... 'press' it to turn it off... You won't have to futz around with trying to return the switch the the normal off centre position. It's also pretty waterproof already and is meant to be mounted to the handlebars ;)

For the rest of it, listen to Martin up there. Although his avatar makes him look like a deranged electronics mad scientist that experiments on himself, he's got a lot of know-how. (12V lead-acid batteries can be quite small, and are very forgiving. Take a look at some of the smaller ones used in home alarm backup batteries.)
 

Martaine2005

May 12, 2015
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Great advice from Gryd3 about a m/cycle indicator switch. It probably has a larger diameter opening than your bikes. You can pack that out with bent tin can or similar sleeve.
Any way, I have just found a new respect for one of the members of this forum. Mr Colin Mitchell.
I didn't know about his 'Talking Electronics' endeavours.
He has a free PDF file to d/l with hundreds of transistor/oscillator circuits, perfect for your project.
Have a look here
If you have any questions, just ask.
Martin
 
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