# DIY LED Bycicle POV

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This instructable is a simpler version of the Ladyada SpokePOV and the Monkeylectric Monkey Light. Unfortunatly, this version cannot spell words of pictures. It can however, make your bike stand out in the dark. This can be built in less than a day with less than \$3.00 worth of parts (less if you have a bunch of LEDs laying around).

I have entered this into the "Get the LED Out" contest so please vote for me and rate my Instructable. This project is great for those people who do not win the Monkey Lights, but still want to have a cool looking bike at night.

*****You can see more of my projects and updates to my current projects on my website: Colvins.ca*****

***For Support on this Project, Please use the forum on my website. Just go to http://colvins.ca and click the forum link on the side bar.***

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## Step 1: Parts &amp; Tools Required

The parts needed for this build are very simple. They are:
-LED's ~ I used four, but you can choose how many, and what colors
-Resistors ~(if needed) Choose resistors that fit your leds and battery (I used 2 100ohm resistors with my 2 volt red LEDs and my 4.5 volt battery
-Batteries~ I used 3 AA batteries to make 4.5volts
-a Switch ~ To turn it on and off
-Zip Ties ~ To attach it to your spokes
-tape
-a Straw ~to hold and diffuse the leds

The tools are also very simple:
-basic soldering tools
-scissors
-hot glue gun

That's it.

## Step 2: The Schematic

The schematic is very simple too. All it is is 3 batteries connected in series to form 4.5 volts, then the LED's with their resistors connected to the battery. Their is also a switch on the negative wire between the batteries and the LEDs. I have attached the schematic below.

## Step 3: Build the Battery Pack

Now comes the fun part... building it! It's very simple, and only requires very basic tools and skills.

First, you need to build your battery pack. I used 3 AA batteries. To do this, glue your 3 batteries together, side by side, so that if you look at the end of the batteries, you will see either +-+ or -+-. This makes a more compact battery pack than if you were to just put your batteries end to end. Now, looking down on the battery, you should see -+-. Tape a short piece of wire to the first battery's negative pole. Tape the other end of the wire to the second battery's positive pole. Now tape a long wire to last battery's negative pole. This will be your negative lead on the finished battery pack.

Now, flip the batteries over. Make sure the battery that the negative lead is connected to is to the right. Tape a long wire the the first battery's positive side. This will be your positive lead. Now tape another short wire to the second battery's negative lead. Tape the other end of the short wire to the last battery's positive pole. Finally, wrap lots of tape around the battery pack. This will prevent the wires from coming loose when the bike wheel is spinning.

## Step 4: Assemble the LEDs

Now we need to solder together the leds. This step is very simple.

Start by soldering the resistor that goes with you LED to the negative lead of your LED. Then, solder a wire to the positive lead of the LED and the other side of the resistor. Cover all of your connections with hot glue to make them water proof.

Now, repeat this step for all of your LEDs.

## Step 5: Build the Light Tube

In this step you will build the tube that diffuses the LEDs.

First, you need to cut two holes in the center of your straw. These will hold two of your leds.

Now you need to decide on a pattern for your leds. I chose to use four red leds, so I did not need this step, but is you have more than one color, you will want a pattern.

Now, glue one of your leds in each end of the straw. Also glue one of your leds in each hole so that the leds are pointing out.

Thats it, you have now assembled all of the main components of the LED POV.

## Step 6: Putting It All Together...

Now, we need to put it all together. This step includes soldering the light tube to the battery pack and inserting a switch.

First, solder one wire of the negative lead of the battery pack. Then, solder the other lead of the switch to all of the LED's negative leads. Finally, solder the positive lead of the battery pack to the positive leads of the leds.

Now you have finished assembling the LED POV. Test it by flicking the switch. If all is good, there should be no smoke and it should light up.

## Step 7: Attach It to Your Bike

Now you need to attach it to your bike. I chose to put it on my back tire, but either should work fine. Using zip ties, attach the battery pack to your spokes. Put it near to center of the wheel. This is because there is less force in the center of the wheel. Now, attach the light tube to the spoke with zip ties.

That's it, you are ready to go.

## Step 8: Results and Possible Improvements

Over all it worked pretty good. The one thing that I noticed is that you need to be going really fast to get the full effect. This could easily be fix by adding a couple more light tubes.

***For Support on this Project, Please use the forum on my website. Just go to http://colvins.ca and click the forum link on the side bar.***

Participated in the
Get the LED Out! Contest

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## 17 Discussions

If you are going to post, you might want to check your answer, eg resistors must be on the positive side, that's silly.. If you want to use fewer resistors take the battery voltage and subtract the voltage drop for each LED eg. 0.7volts. Use ohms law r = e/i, if you leds use 15 ma each, then the "extra" juice you need to get rid of is 1.7 volts so r the resistor needed is 1.7 volts/ 0.015 amps, requires a 120 ohm resistor. You gain less power use if you use a series circuit, however if one burns out they all will go dark.

I love the simplicity and the low budget on this! Thanks for this. The item I would change on this is I would use a waterproof 3 x AA battery holder so I could use rechargeable batteries on this. adafruit has one for 4 bucks or so. I am going to try this and maybe use vinyl tubing as well instead of the drinking straw.

If there was no resistor the LED would be drawing to much power and depending on the voltage in sense "burn out"

Would it matter if you were to reverse that schematic by placing the resistors and switch on the positive lead?

I'm really happy you remembered to put the batteries as close to the center as possible. Else that project woudn't have lasted long.

not necessarily. If you put them in series is the first one will get the most power, the next will get less, then the next will get even less, and so on and so forth. This will lead to the first one being brighter, but also potentially burning out faster.
tl;dr: dont wire LED's in series.

If you wire them in parallel with individual resistors, they all get the same power and all should have the same brightness, and all last the same amount of time before burning out.

just so u know you can also buy battery packs at radio shack so you don't have to re glue your batteries together all o' the time.