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This instructable is created and provided by the Edmonton Bicycle Commuters' Society (EBC) (http://edmontonbikes.ca , http://www.facebook.com/edmontonbikes , http://twitter.com/edmontonbicycle ), a non-profit organization that supports all cyclists in Edmonton by providing advocacy, education, free services at events, affordable used and new parts, and bicycle recycling.
EBC also operates BikeWorks, a fully-equipped, volunteer-run community bike workshop, where volunteer mechanics teach & help members of the public to learn how to fix their bicycles. EBC also sells used bikes.
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This is the introductory video to building a high-power three LED bicycle light. The design here has 3 modes: High, Medium, and Strobe (blinking), and runs on a voltage between 5-10V. The price of the light, including batteries, charger, and worldwide shipping, is about $50 US. Including batteries, it weighs about 200 grams, and should last about 1.5 hours on high mode (and significantly longer on medium or strobe modes).
This light is something that you can build with minimal investment in components and small hand tools. You don't need to know electronics: there are just 18 solder points, 6 drill holes, a bunch of hot glue, and a few screws. It doesn't require a microcontroller. You don't need to know what an Arduino is. It doesn't require you to fabricate metal, use PVC tubing, laser cut anything, or weld. With a bit of experience (e.g. if, for whatever reason, you make a half-dozen), you can put one of these lights together in less than an hour.
The Edmonton Bicycle Commuters' Society occasionally runs in-person courses on designing and building your own custom bike lights: this design or one customized to suit your needs.
This light is the same brightness, about 600 lumens, as the "Three P4" design here: http://edmontonbikes.ca/downloads/bikelights09/ , but the design in this video is cheaper and easier to build and use, and has a cleaner design.
This light works in thunderstorms, blizzards, and has been used in temperatures below -30C.
That power source can be two lithium-ion rechargeable batteries, or four to six alkaline 1.5V cells in series, or five to seven rechargeable NiMH or NiCad 1.2V cells in series (any of AAA, AA, C, or D shapes). A 6V generator would also work, provided it can provide about 9-12W of power (this is a bit high for the average bike generator).
The parts you will need are:
=== POWER SOURCE ($21 US) ===
=== LIGHT ($29.20 US) ===
=== TOOLS (if you don't already have them or can't think of a way to fake it) ===
=== OPTIONAL TOOLS (you don't really need them, but they're handy) ===
All DX parts can be purchased from http://www.dealextreme.com/ . Prices there include worldwide shipping. You may be able to source equivalent (or better) parts for less money, or make substitutions, but I've provided the DX numbers to make things easy for those that just want to follow a detailed shopping list and know that all the parts will work together. When ordering the part numbers listed above, you'll end up with extra components, since some of them come in multiples.
Be warned: I have waited up to 4 months for parts to arrive from DealExtreme. I've always received my items, or received my money back if they couldn't ship it or shipped a wrong/defective item. But some times it's a long, frustrating process. They don't make you jump through hoops, but they can be extremely slow to respond.
They're pretty much a lousy retailer and unacceptable by any normal standards, but if you want to save a few pennies and not leave your house, and you can afford to wait potentially forever, they might barely satisfy your needs. If you work at it, you can often find the same (or better) items on eBay for less money.
EBC also operates BikeWorks, a fully-equipped, volunteer-run community bike workshop, where volunteer mechanics teach & help members of the public to learn how to fix their bicycles. EBC also sells used bikes.
---
This is the introductory video to building a high-power three LED bicycle light. The design here has 3 modes: High, Medium, and Strobe (blinking), and runs on a voltage between 5-10V. The price of the light, including batteries, charger, and worldwide shipping, is about $50 US. Including batteries, it weighs about 200 grams, and should last about 1.5 hours on high mode (and significantly longer on medium or strobe modes).
This light is something that you can build with minimal investment in components and small hand tools. You don't need to know electronics: there are just 18 solder points, 6 drill holes, a bunch of hot glue, and a few screws. It doesn't require a microcontroller. You don't need to know what an Arduino is. It doesn't require you to fabricate metal, use PVC tubing, laser cut anything, or weld. With a bit of experience (e.g. if, for whatever reason, you make a half-dozen), you can put one of these lights together in less than an hour.
The Edmonton Bicycle Commuters' Society occasionally runs in-person courses on designing and building your own custom bike lights: this design or one customized to suit your needs.
This light is the same brightness, about 600 lumens, as the "Three P4" design here: http://edmontonbikes.ca/downloads/bikelights09/ , but the design in this video is cheaper and easier to build and use, and has a cleaner design.
This light works in thunderstorms, blizzards, and has been used in temperatures below -30C.
That power source can be two lithium-ion rechargeable batteries, or four to six alkaline 1.5V cells in series, or five to seven rechargeable NiMH or NiCad 1.2V cells in series (any of AAA, AA, C, or D shapes). A 6V generator would also work, provided it can provide about 9-12W of power (this is a bit high for the average bike generator).
The parts you will need are:
=== POWER SOURCE ($21 US) ===
=== LIGHT ($29.20 US) ===
=== TOOLS (if you don't already have them or can't think of a way to fake it) ===
=== OPTIONAL TOOLS (you don't really need them, but they're handy) ===
All DX parts can be purchased from http://www.dealextreme.com/ . Prices there include worldwide shipping. You may be able to source equivalent (or better) parts for less money, or make substitutions, but I've provided the DX numbers to make things easy for those that just want to follow a detailed shopping list and know that all the parts will work together. When ordering the part numbers listed above, you'll end up with extra components, since some of them come in multiples.
Be warned: I have waited up to 4 months for parts to arrive from DealExtreme. I've always received my items, or received my money back if they couldn't ship it or shipped a wrong/defective item. But some times it's a long, frustrating process. They don't make you jump through hoops, but they can be extremely slow to respond.
They're pretty much a lousy retailer and unacceptable by any normal standards, but if you want to save a few pennies and not leave your house, and you can afford to wait potentially forever, they might barely satisfy your needs. If you work at it, you can often find the same (or better) items on eBay for less money.
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Signing UpStep 1Build the battery box
(Apologies for the focus. Still learning how to use my camera.)
Step 1: Clip away the four plastic protrusions/tabs at each end of the box (where the battery terminals will sit).
Step 2: Drill a small hole above each point where you clipped away the plastic. Drill as high as possible so that your battery-holder terminals will be near the centre of the battery terminals.
Step 3: Ensure that your screws and springs are conductive using a connectivity tester. If your multimeter doesn't have an explicit connectivity tester, you can measure resistance instead. A resistance of 0 Ohms (or under ~4 Ohms) is the same thing as a connection, which is the same thing as a closed-circuit (which is the same thing as a short circuit). This is what you want between the head of your screw and its tip.
Step 4: Drive one screw into a hole from the inside of the battery box. Drive the second screw into the opposite corner.
Step 5: Use pliers to pull open one end of the spring and feed it into one of the remaining holes, from the inside of the battery box. Turn it through about a turn and a half. Do the same with the other spring.
Step 6: Check to see if your batteries fit your battery box. If not, make appropriate adjustments of the springs and screws. Make sure you didn’t skip Step 1.
Step 7: Remove the batteries. You must not try to solder with the batteries still in the case.
Step 8: File the tips of the screws down so that you don’t stab yourself. This is an optional but recommended step.
Step 9: Strip a short piece of wire: strip about 1 inch from one side, and 1 cm from the other. Wrap the long stripped section at least one full turn around one screw, so that it wraps back on itself. Twist the other end of the wire around the nearby spring. Solder both in place. Make sure that the solder connects your wire loop on the screw. Test that the screw is electrically connected to the spring, using your multimeter. Touch the probes to the screw and the spring (not to your solder or the wire--you don’t want to bypass your solder points).
Step 10: Cut two wires, about 6-10 inches in length (speaker wire works well here because it comes paired already). If your wires are differentiated, select which colour will be your positive wire and which will be your negative. Strip one end of the “positive” wire about one inch. Wrap it around the screw and solder it. Strip a short length of the “negative” wire and wrap it around the spring. Solder it too.
Step 11: Strip short lengths of the other ends of the wires. Test the connectivity of these to the screw, spring, and each other (they shouldn’t be shorted to each other).
Step 12: Write polarity signs on the inside of your battery box. Screws are +ve terminals, springs are -ve terminals.
Step 1: Clip away the four plastic protrusions/tabs at each end of the box (where the battery terminals will sit).
Step 2: Drill a small hole above each point where you clipped away the plastic. Drill as high as possible so that your battery-holder terminals will be near the centre of the battery terminals.
Step 3: Ensure that your screws and springs are conductive using a connectivity tester. If your multimeter doesn't have an explicit connectivity tester, you can measure resistance instead. A resistance of 0 Ohms (or under ~4 Ohms) is the same thing as a connection, which is the same thing as a closed-circuit (which is the same thing as a short circuit). This is what you want between the head of your screw and its tip.
Step 4: Drive one screw into a hole from the inside of the battery box. Drive the second screw into the opposite corner.
Step 5: Use pliers to pull open one end of the spring and feed it into one of the remaining holes, from the inside of the battery box. Turn it through about a turn and a half. Do the same with the other spring.
Step 6: Check to see if your batteries fit your battery box. If not, make appropriate adjustments of the springs and screws. Make sure you didn’t skip Step 1.
Step 7: Remove the batteries. You must not try to solder with the batteries still in the case.
Step 8: File the tips of the screws down so that you don’t stab yourself. This is an optional but recommended step.
Step 9: Strip a short piece of wire: strip about 1 inch from one side, and 1 cm from the other. Wrap the long stripped section at least one full turn around one screw, so that it wraps back on itself. Twist the other end of the wire around the nearby spring. Solder both in place. Make sure that the solder connects your wire loop on the screw. Test that the screw is electrically connected to the spring, using your multimeter. Touch the probes to the screw and the spring (not to your solder or the wire--you don’t want to bypass your solder points).
Step 10: Cut two wires, about 6-10 inches in length (speaker wire works well here because it comes paired already). If your wires are differentiated, select which colour will be your positive wire and which will be your negative. Strip one end of the “positive” wire about one inch. Wrap it around the screw and solder it. Strip a short length of the “negative” wire and wrap it around the spring. Solder it too.
Step 11: Strip short lengths of the other ends of the wires. Test the connectivity of these to the screw, spring, and each other (they shouldn’t be shorted to each other).
Step 12: Write polarity signs on the inside of your battery box. Screws are +ve terminals, springs are -ve terminals.
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Enjoying this much more than the duct taped flashlight I used last fall.
There's a GU10 housing that's the same as this one, only the lens is for a single LED. So if you use:
- Single-LED GU10 housing
- Cree XML LED
- And an appropriate buck driver (you wouldn't want a boost driver for a single LED)
You'd have a brighter, more efficient light, for the same price! And it'd be less work to build.
One lingering advantage to the 3-LED design is that you can use LEDs with three different colour temperatures in one light, to get a much better spectrum covered. So you could put in a 3W warm LED instead of one of the P4s.
I can't measure lumens, but I can say:
At 1.5A, my XML-T6 is not as bright as this 3-LED design at 0.8A. (the 3-LED design is consuming more power, though, since it's running at over 10V)
At 3A, my XML is brighter.
I tend not to run either light at max power, though. They're both plenty bright enough for me (on street and in dark trails) on the lower settings.
So now I've actually looked them up!
The XML is 2.7-3.3V over its current range. It's nominally 3.3V at 3A. Which is 10W.
The P4 is 2.9-3.8V over its range. At 0.8A, it's about 3.65V. So all three together, at high power, consume about 8.76W.
Brighter than what? This instructable never mentions P7s. The full details of the components are all linked to in the first page.
LEDs don't "use" more power than each other. LEDs have specified operating conditions, and some LEDs have a higher maximum power rating than others. That doesn't mean that you have to run them at their maximum, nor does it imply that a higher power LED is brighter than a lower power LED.
If you feed two LEDs the same amount of power, the more efficient one, by definition, will be brighter.
If you feed a less efficient LED more power than a higher efficiency LED, you can balance it so that they emit the same amount of light (at their respective power levels).
If you want to know which LED is more efficient, you need to look at the datasheets for the specific LEDs and read the data. Manufacturers supply the datasheets online for their products so that you can compare them and see if they suit your application.
I believe that the XML is probably more efficient than a P7, though I don't know the specs for the P7. You can look that up. If that's the case, then at the same power, the XML will be brighter. I have no idea which has a higher maximum power.
1) Lots of dynamos say 3W, but are able to put out more.
2) The driver will likely drop into low-mode, and may or may not be happy with your power source, but you'd really have to test.
3) For running off a dynamo, this design isn't optimal anyway, and you'd be better off running only one or two LEDs at a lower current, and doing it without a driver, but instead using a couple resistors, a supercapacitor (for a standlight), and some additional simple circuitry.
4) Alternatively, use your dynamo (with appropriate circuitry) to charge batteries, and use those batteries to power this light.