bike cellphone charger chris battaglia (me) ajeetesh govrineni (ee) kellen warriner (ie)
TRANSCRIPT
Bike Cellphone Charger
• Chris Battaglia (ME)• Ajeetesh Govrineni (EE)
• Kellen Warriner (IE)
Project Summary and Background• Second generation project (see right)• Design a bicycle cell phone charger for use
in Haiti and other underdeveloped countries•Includes generator, breadboard, and phone holder
• Total material cost should be <$15 and manufacturable on-site in Haiti•No heavy machinery used (lathe, mill, etc)
• Time needed to charge a phone must be reasonable for the user•Nokia and Blackberry phones. Primarily target is the former
• Design must be simple, robust, easily repaired/replaced, and adjustable
Old Design
Our Design
Design SummaryConsists of two main sub-assemblies1. Generator Housing
• Generator is enclosed in plastic cylindrical housing with shaft extending out
• Shaft is held against the tire of the bike, friction turns the shaft
• Held to bike frame via two rubber-lined clamps joined with a bolt and wing nut
Consists of two main sub-assemblies2. Phone Holder
• Contains breadboard and power connector
• Comfortably holds Nokia and Blackberry phones and adjoining cables
• Attached to handlebar of bike with two Velcro strips
Product Performance & Information• Half-charged a Nokia phone in 25 minutes
• Takes approximately 6-8 hours of continuous use to deplete the battery
• Requires 1-4 hours (based on speed) to fully charge a phone• Approximately 1:2 Work to Use Ratio on average
CONTAINED IN KIT
BicycleFrame
AttachmentConnecting
Power Cable
Phone Holder + Breadboard
Generator + Housing
Phone
USB Cable
Customer Needs and Results# Description Target Value Actual Value Result
1 Voltage Output 4.8-5.2 V 3.9-4.4 V Achieves minimum value at 9.67 mph.
2 Current Output >250 mA 110-410 mA Achieves target value at speeds >13.5 mph. Begins charging at 9.67 mph at 110 mA.
3 Material Cost <$15 ~$14.50 Meets target price, but only just.
4 # of Machines Used in Construction 0 0 Only hand/power tools used in construction.
5 Duration on Rough Road Conditions Before Misalignment >1 hour >1 hour No misalignment after an hour on rough road
conditions or repeat use on smooth conditions.
Quantitative Objectives
# Description Pass/Fail Result
6 Charger fits standard phone connectors Fits any standard USB cable (typically shipped with phone)
7 Aesthetically pleasing; provides user feedback Reactions to the design have been positive
8Easy to install, maintain, and use While it’s fundamentally easy to install, proper installation
takes several fine adjustments, instruction, and trial and error to do correctly
9Protects user safety While a potentially minor issue, the breadboard is
uncovered and may present a hazard. The generator shaft also becomes painfully hot to the touch after use.
10 Simple to manufacture CAD drawings have a high tolerance, process is very simple
Qualitative Objectives
~~
TestingTest Engineering Spec Tested Spec Test Pass/FailElectrical Testing Charge All Phones
Universal Connection Tested with USB Bike Charge Test Pass
Output voltage
4.7 V -5.3 V 4.8 V - 5 V Bike Charge Test Pass
Max Current
>750 mA >730 mA Bike Charge Test Pass
Current output at average biking speed
>750 mA 250mA< current < 800mA Bike Charge Test Pass
Mechanical Testing Rough Road Test
None Rough Road Rough Road Test Pass
Environmental Testing
Water Test Resists WaterIEC 60529
IP water test: Level 3 spraying water
Water Test
Pass
Dust Test Resists DustIEC 60529
IP dust test: Level 5 dust protected
Dust Test Pass
Impact Test Generator Does not break when dropped/bike crashIEC 60529
IP impact test: Level 5 (500 grams dropped from 40 cm)Actual test was 1 meter drop height
Drop Test Pass
Impact Test Phone Housing
Does not break when dropped/bike crashIEC 60529
IP impact test: Level 5 (500 grams dropped from 40cm) Actual test was 1 meter drop height
Drop Test Fail
General Testing
Bike Tire Range 60.6-71.1 cm 26 inch bike wheel (66cm) Measurements Pass
Total Cost
< $ 15 <$15 Pass
Weight
Less than current Less than Current Weight Test Fail
Number of Machine Tools Less than 0 Less than 0 Pass
Number of People to Produce
1 person 1 person Pass
Number of Tools to Install Less than 1 Zero (Hands free installation)
Pass
Cost to Install 0 0 Pass
Current Generated At Various Bicycle Speeds
0
50
100
150
200
250
300
350
400
450
0 2 4 6 8 10 12 14 16 18 20
Bike Speed (mph)
Cu
rren
t (m
A)
• Current/Voltage test• Output at various speeds• See above graph
• Rough road test• Road bike on rough terrain,
checked generator positioning
• Impact test• Drop test
• Environmental Damage test• Water and dust test
Suggestions for Future Work
• Better means of holding the nub of the generator shaft against the tire•Optimize potential output•Simplify installation
• Cheaper components / overall cost reduction•Certain items are large contributors to the overall cost
• Powerjack Cable, etc• Better generator? Remove breadboard?