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====== Bike-Powered Cell Phone Charger ======

===== What is this lesson? =====

Bikes are the most effective use of human-powered energy, so why not attach your bike to a motor to charge your mobile while you go to town?  This is a practical and design-based lesson, for use once students know how motors and gears work.

If this lesson interests you, there's lots to do:
  * Write the [[teachers guide|teacher's guide]]
  * Adapt the default [[evaluation form]]
  * Design and upload [[illustrations]]
If you're interested in doing any of that, great! Leave a note on the [[:lesson index#Bike-Powered Cell Phone Charger|lesson index]] that you're taking charge.

Whether or not you're interested in writing a part of this lesson, please leave lots of comments on this page, the teacher's guide, and the evaluation form. Thanks!

===== What this lesson teaches =====

==== Science/Engineering principles ====
Not applicable.
==== Technical skills ====
Millimeter-scale precision to utilize the motor effectively, circuit design and soldering
==== Design skills ====
prototyping, design a charger to attach to your bike
==== Other skills ====
none
==== Deliverables ====
Students build a working bike-powered cell phone charger.

===== How this lesson fits into the curriculum =====
PEN lessons that meet the requirement are noted in brackets.
==== Curricular knowledge and skills ====
Basic circuits, batteries (battery lesson), gears, motors (shake dynamo)
==== Extracurricular skills ====
probably none
==== Follow-up lessons ====
none

===== Practical Work =====
==== Demonstrations ====
Teacher demonstrates how the spinning bike wheel will spin the motor shaft.
==== Experiments ====
None
==== Design/Build Work ====
Students will build a mechanism for spinning the motor shaft on the bike wheel. They will then design a protective cover to attach the motor to their bike.


===== Logistics/Resources =====
==== Building materials ====
Motor, charging circuit, mobile charging cable, bike spoke, enclosure, plastic bit to grip the wheel, rods
==== Demonstration materials ====
Cell phone
==== Other materials/equipment ====
Multimeter to test voltage
==== Classroom logistics ====
Probably one teacher per 12 students, groups of 1-4 students per bike charger

===== Optional Questions =====
**Why should students want to participate in this lesson?**

Build something awesome

**Why should teachers want to teach it?**

Useful demonstration of the science from previous lessons

**If this lesson (and its prerequisites) were the only PEN lessons someone took, what should they be able to do?**

Turn a motor into a cell phone charger. Design and build a protective case to mount charger on bike.

**If you had to teach this lesson tomorrow morning, what would you spend tonight working on? (assuming that materials were not an issue)**



**If you hadn’t taught this lesson before, what questions would you have for someone who had taught a very similar lesson?**



**If the only materials available were broken radios, TVs, and computers, could you do all the electronics in this lesson? (assuming you had solder, soldering irons, etc.) If not, what would be missing?**

If you had a good motor (from a broken printer?) and a cell phone charging cable, then possibly.

**If the only structural materials available were dish-cloths, cardboard, and plastic bags, could you make the mechanical bits of this lesson? (assume equipment as above) If not, what would be missing?**

No-- something more solid and durable for the case.