Introduction: Very Bright Bike Light Using Custom Light Panel PCBs
If you own a bike then you know just how unpleasant potholes can be on your tires and your body. I had enough of blowing out my tires so I decided to design my very own led panel with the intent to use it as a bike light. One that focuses on being EXTREMELY bright to help see pot holes and for night time bike path riding. Now I know you're thinking that it won't be car friendly but for this bike light I added a dim mode that will be used for street riding while the bright mode will be used for paths. Everyone wins!
The beautiful part about this light is that I designed the light panels to be adaptable to more than just bike applications. It can be used for anything requiring extra light.
I will describe the panels more in depth in the next few steps but if you like the design and want to order your own boards feel free to use the gerber files attached in this step! Let's get to it!
My panel uses 42 10mm leds and 14 resistors. The resistor value I used for my panel is 120ohm 1/4 watt. This value was calculated and tested and has proven to work great for this panel. The value you need may vary depending on your set up! My bike light uses two of these panels.
10mm white leds
resistors I used 120ohm
Step 1: Watch the Video If You'd Like
I made a video for my youtube channel covering the build. Stop on by if you'd like!
Step 2: The Schematic and Board
As a reminder I did include the files for this board in the first step if you wish to send out for your own copies!
My panel consists of 42 10mm white leds in a 3 in series in parallel with the other groups. I designed it with the intention of using it for other projects so I didn't feel the need to include any control circuitry in the design. I wanted to make it as simple as possible for future use. The board also features four mounting holes in the center.
Step 3: Assembly
Soldering all the leds and resistors is the most time consuming part but it can help you perfect soldering which is always good! Due to the boards layout it is really easy set up.
Step 4: Making It Into a Bike Light Part 1, Supplies.
If all you wanted was an easy light panel then you're all set! If you wanted to see how I used two of these to create a bright bike light then follow along :)
In order to make this a stand alone unit fit for a bike light I used a USB battery pack, two voltage boosters, a relay, two switches, two cellphone bike mounts, scrap wood and an ugly Christmas tin to house everything.
I had no intentions of using an ugly Christmas tin to mount everything in but it turned out to be a perfect fit for everything and it just worked out. I could paint the tin but the green pcbs and red tin seem to be a perfect match. The second image is that of the voltage booster. You can find these exact ones on amazon for pretty cheap!
Step 5: Making It Into a Bike Light Part 2, Power Supply.
Before I get into the details I would like to say that this is not an ideal power supply in the sense that I used what I had on hand and it can be made better with the right supplies.
I wanted to add a dim mode to my light to be courteous of cars so I used two voltage boosters with one set to 12volts and the other set to 9volts. The 12volt booster acts as the bright mode by supplying the light panels the full voltage supply and the 9volt booster supplies a lesser voltage which results in dimmer leds. Changing the input voltage is a very easy way to dim the leds but this can be achieved a number of different ways in arguably more efficient ways. I used what I had.
I used a SPDT relay to change the voltage supply to the leds. The common pin of the relay is connected to the positive input on the led panels, the normally closed pin of the relay is connected to the 12volt booster and the normally open pin is connected to the 9volt booster. When the relay isn't activated the 12volt supply is selected by default, when the relay is turned on by supplying 9volts to the coil it'll switch the normally open to closed and select the 9volt supply, If a switch is added in between the coil of the relay we can now control it. The only reason I used a relay is because I didn't have any SPDT switches only SPST, again I worked with what I had.
Both of the boosters are wired in parallel and accept the 5volts from the USB battery pack. Both of the boosters being in parallel show no signs of major power loss due to only one having an active load at a time however they both still draw current so this does effect the battery life. If I really wanted to I could've used just one booster with all the right parts but I didn't want to order anything and have to wait.
Step 6: Making It Into a Bike Light Part 3, Tin.
If I had a 3d printer this beautiful use of an ugly Christmas tin would have never happened. It is so weird how perfect this tin worked out. Everything just kept going right when I landed on using it for the housing.
To prep the tin I used epoxy to mount two wood posts on the inside. These posts would separate the electronics from the metal and supply a secure place to screw into for the top assembly. After finding out where I wanted the switches and DC jack for charging to be placed I screwed two of my light panels to a piece of wood that would fit inside the tin and on top of the posts, this wood will be screwed to the posts later on. I mounted all of the electronics using heat resistant epoxy to the underside of the wood then I soldered everything according to my power supply diagram. The red on the wood indicates a "keepout" zone which is a zone to be avoided when mounting the electronics. These zones sit over the switches, posts and DC jack. The use of heat resistant epoxy will help keep all the parts in place when they warm up. The battery pack was secured using double sided tape. I would advise against the use of epoxy on batteries due to the chemical reaction that generates heat.
Step 7: Making It Into a Bike Light Part 4, Mount.
The end result was neat and compact however it wasn't light. I ended up using two cellphone bike mounts to connect the light to my bike. I bolted the mounts to the tin. You can use one mount but I found that two provides more security. I also added a piece of wood to the outside of the tin for more support.
The cellphone mounts still had some slop to them which helped with absorbing shock while riding around. A neat little surprise!
Step 8: Light Up the Roads!
Now its ready to mount to your bike, fire it up and go for a night ride! Thanks for making it this far and I hope you enjoyed my ible! If you end up making your own please let me know in the comments below!