In this instructable I'll show you how to make some useful electronic gadgets for your bike. The instructable contains a solar power bank with a very high 7000mAh capacity that can be recharged with a build in 5v solar panel or with a recycled CPU fan. The full cost for me was less then 10 bucks, but I salavged many components from old electronic devices. The powerbank uses 3 pieces of 3.7 volt, 2360mAh 18650 cells that were salvaged from an old laptop.
I love green energy and automatization projects because they can help us.
I go everywhere with bike in my town and sometimes, while cycling, my phone discharges. At the sommer I participated in a BIKE-CAMP, where my phone discharged and it was neseccary to speak with my parents. I've got a gash on my knee and I can't get medical services, It was terrible to cycle with this gash. So I decided that I'll make a device for the case of an emergency.
The solar power bank have 3 build in 18650 cells. Can charge directly your phone or the build in battery or 2 pices of AA battery. The solar panel generates 6.4 volts at 200mA that is regulated to 5 volts. Uses a 5v step up module to charge your phone from the battery and a Lithium charger module. So the power bank have four modes of charging that can be switched with ON-OFF-ON switches.
This device can charge up even AA batteries for the bike light. It's a very especial lamp, because conforms to the eyesight vicissitude. Consume only as much energy that you need to see clear the road. Exampe if the street lights are on this lamp will light weak, but if there are't external lights will light bright. The life of your battery may be doubled with this technology.
The wind turbine is made from an old CPU fan and you'll need only some diodes and a female USB port to build this. The output voltage is usually 5 volt but the current is small, but can charge the power bank easily because don't regulates the input current.
- Uses pure green energy to charge up anything.
- It's a very cheap project
- No need to cycle for charging, can be used a simple solar or wind charger if you take off the bike.
- The life of your battery in your light may be doubled.
Now go read some concepts that you'll need to know for this project.
Step 1: Concepts
AC: Alternating Current-The voltage of the power source is switching between negative and positive voltage.
Diode Bridge: It's a circuit builded from diodes turns AC into DC.
If you have other questions write in a comment.
Step 2: Gather Parts and Tools
- some soldering experimence in soldering
- soldering iron
- glue gun
- metal ruler
- cutting tool
- crafting tools
- electrical tape
- rotary tool
For the Solar Power Bank:
- a female USB port
- 5v step up circuit
- old phone or laptop battery or 3 18650 cells
- 5v, 160mA-1A solar panel
- 2 pieces of ON-OFF-ON switches
- a simple switch
- 2 AA battery holder
- USB Lithium ion charger module
- some wires
- 7805 voltage regulator chip
- a germanium diode
- plastic sheet
- support for your bike
You can get plastic sheet for free from a local commercial factory. They uses plastic sheet for their posters. Usually they give me free. But if you can't get go and buy from the local hardwere or DIY store.
For the Wind Turbine:
- an old CPU fan
- 4 germanium diodes
- a female USB port
- a 47uF capacitor
- 5v step up circuit or a Joule Thief
- support for your bike
My CPU fan was very big and generated more than 5 volts while cycling, so I just regulated the voltage to 5 volts using a 5v1 zener diode. But if your CPU fan can't generate so much volts simply use a step up circuit.
For the Smart Light:
- an old bycicle lamp (powered with at least 3 batteries)
- a 2N2222 transistor
- a lIght depending resistor
- a 220k ohm resistor
- and some hook up wires
You need to know that I used a joule thief to ptotoype the circuit,but the real lamp is powered by 4 AA batteries.
Click on the parts to get a link for it.
Step 3: The Power Bank
Prepare your workspace and begin crafting. Get your solar panel and regulate the output to 5 volts using a the 7805 regulator. Cut a small piece of PCB then make a hole on it. In this hole you can leave space for the regulator chip. Use your glue gun and fix the solar panel on the plastic sheet.
See the circuit on the 1st picture. Follow this and solder the circuit together.
Step 4: Solder the Switches
Following the circuit diagramm solder the two switches and the direct USB port to the regulated solar panel.
Step 5: Choosing the Power Supply for the Build in Battery
You can use old phone batteries or laptop batteries. I used these salvaged 18650 cells to make a battery pack from them. Simply soldered together and fixed with electrical tape. Check the voltage then charge up using the charger module. That's so easy.
Step 6: Test the Batteries Using Your Phone
Connect the wires together and try if works. My phone can be charged with 3 batteries for about 3.5 times to 100%.
Step 7: More Soldernig
Now you'll need to solder everything together. First add the AA battery holder then the 3.7 volt battery pack. Then solder the stepup module to the battery, but add a switch between the battery and the step up circuit. Follow the pictures and be careful! Never short the circuit. These lithium ion batteries may cause fire, because have a very high current.
Once when I shorted a cell the full wire burned down and the solder fused. Generated a very big smoke.
Please be careful!
Step 8: Use Your Rotary Tool to Make the Case
Using your knife or cutter cut a small piece of plastic. Get your rotary tool or drill and make every hole for your "User Interface". Two holes for switches and two holes for the USB outputs. Then using your glue gun fix there everything. Test the cirtcuit sometimes while working. If everything works use a super glue and glue together the parts. At the end test the device with your phone.
Step 9: UPDATE Protection Circuit
The protection circuit is salvaged from an old phone battery. Read this tutorial for the detailed tutorial. Simply solder the battery to the protection circuit output and the wires to the output. If the voltage of the cell drops under 3 volts the battery will stop working.
Why is this important?
-Because if the battery pack's voltage drops under 2.7 volts the capacity and the battery will be damaged by overdischarging.
Step 10: How to Charge Up?
I bought the charger modules from the eBay but still shipping. So I used 9 volt vlips to make a charger connector for the power bank. With this you can charge up the battery with the wind turbine or with a computer or wallplug USB port. WIth the super glue start to create a box.
Step 11: Last Modifications
Wrap the circuits into electrical tape. This will save them from shorting. Finally cut the last piece of plastic then glue on the bottom of the device. Now you're almost done.
Step 12: The Bike Featurette
The device looks really awesome. Everything works perfect. Now glue the bike support on any side.
Your new solar power bank now is done.
Step 13: The Wind Turbine
Before you start need to know that this wind turbine can't charge fast because its current is not so high like a wallplug charger. But it's helpful in the case of an emergency. The max current is about 150 mA, but usually generates 60mA on 5 volts.
You have two ways to make this. If you have a smaller wind turbine that can't generate more than 5 volts you'll need to increase the voltage. Or if you have a big one like me need to regulate the voltage to 5 volts using a 5v1 zener diode.
Now let's begin!
First take off the propeller then check the circuit. You have 3 legs on the turbine. Solder to each one piece of copper wire. Put back the propeller then turn your multimeter on AC mode and check wich of these three legs have the higher voltage, In may case that was the green and the white wires. Simply desolder the third wire. Use your glue gun agian and fix the wires on the back of the fan.
If you're done with this step you'll need to make an AC/DC converter.
Step 14: AC to DC
Get four germanium diodes and following the circuit diagramm build it on a PCB. I've added one plus capacitor for the perfect DC output. Solder the input pins to the wires of the CPU fan. Now you have a DC wind turbine. Solder the output legs to the step up circuit or to the regulator.
Step 15: The 5v Regulator
I made this using a 5.1 volt zener diode and a 100uF capacitor. Soldered together on a PCB then. After this connect to the DC output of the turbine.
Step 16: How to Suit on Your Bike?
Glue the circuits on the fan and glue there one more bike support module. Now you're done, go and test it.
Step 17: Testing
If you connect CPU fan to the power bank via the USB cable and blow the charging begins. How I tested? Used my multimeter and checked the voltage before and after the charging. The voltage increased 0.01 volt in a minute. That isn't so much but after a few hours of biking would charge some valuable percents.
Step 18: The Smart Light
For testing I used a joule thief power supply but on my bike works with 4 AA batteries. If the light depending resitsor "feels" darkness the circuit starts working. I've prototyped on a breadboard using 4 LEDs but in the next two steps I'll show you how to insert this circuit in your bike light.
Step 19: Soldering
I've used a 100k resistor and removed the 300 ohm resistor. Solder everything together on a small piece of PCB.
Leave long legs for your LDR because it needs to came out from the case of the light. If you're done try to insert this circuit into the bike light.
Step 20: How to Insert the Circuit?
• Don't use the 330ohm resistor because the light will be weakly
• Leave your LDR free because it needs to feel the vision conditions