Pedal Power
Pedal Power for the Occupy Movement
To support the self-sufficiency of Occupy member sites, the Pedal Power group aims to facilitate the low-cost construction and effective usage of pedal-powered electrical generators and related technologies.
The goal for this design was low cost, with most materials sourced from Home Despot and/or local hardware stores. Can be built relatively easily by anyone with access to drill press and basic tools. Circuitry includes voltage regulator ($1.50 from digikey), a few capacitors/resistors, and a diode.
11/26/11: UPDATE IN PROGRESS
Contact Info
Group email: pedalpower@mit.edu
List admin: moallem@mit.edu
(** PLEASE DO NOT RELOCATE OR RADICALLY MODIFY THIS PAGE WITHOUT FIRST CONTACTING LIST ADMIN. KTHX **)
Parts/Materials List
"A-frame" bicycle stand
Rear legs: TWO (2) x 20" lengths of 1" x 1" (cross-section) rectangular steel tubing
- e.g.,
- Alternatively, can use up to 2" x 1" (cross-section) rectangular steel tubingfor added stability
Rear cross-piece(s): TWO (2) x 12" lengths of 1" x 1" (cross-section) rectangular steel tubing
- e.g.,
- Alternatively, can use single piece of 2" x 1" rectangular steel tubing
Front legs: TWO (2) x 20" lengths of 1-inch angle steel '
- e.g., http://www.homedepot.com/h_d1/N-5yc1v/R-202183502/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053
- Alternatively, can use 20" lengths of 1" x 1" rectangular steel tubing
Front cross-piece: ONE (1) x 16" (minimum, up to 30" maximum) long rectangular steel tubing, cross-section 1" x 1" (Note: If adding optional rubber feet, use longer front cross-piece for wider, more stable stance.)
Front-back connectors: TWO (2) x 20" long steel flats
[SPECIFY FASTENER HARDWARE!!! ]
____________________
Rear-wheel (skewer) supports:
TWO (2) x 3/4" diameter (imperial size 3/4) socket cap bolts, length: 5" (Note: Can alternatively use hex-cap bolts; lower cost, but additional machining required)
FOUR (4) x size 3/4 Hex nuts
____________________
Generator and mounting assembly:
ONE (1) x 24V DC motor (100 to 350 watt)
ONE (1) x heavy-duty door hinge
ONE (1) x strong L-bracket, at least 3" long on one side
TWO (2) x mounting plates (approx. 5" x 5", either steel or thick aluminum)
ONE (1) x roller bearings (should fit motor shaft perfectly)
ONE (1) x roller: solid aluminum cylinder, 1.25" to 1.5" diameter (Note: Can alternatively use Nylon cylinder with thin aluminum pipe as sheath)
[SPECIFY BRACKETS, FASTENER HARDWARE, AND DISTAL ROLLER SUPPORT!!! ]
[INCLUDE EXAMPLE LINKS!!!]
____________________
Electronics:
ONE (1) x low-voltage schottky diode
- e.g., http://search.digikey.com/us/en/products/SR1045-TP/SR1045-TPMSCT-ND/2334476
- e.g. (alt), http://search.digikey.com/us/en/products/MBR1645G/MBR1645GOS-ND/918588
- Note: Regular diode will work, but schottky diode minimizes power loss
ONE (1) x adjustable positive voltage regulator
- e.g., 5-Amp low dropout (LDO) linear voltage regulator: http://search.digikey.com/us/en/products/LD1084V/497-3413-5-ND/669183 [LD1084V Datasheet]
- e.g. (alt), 7.5-Amp LDO linear voltage regulator: http://search.digikey.com/us/en/products/LT1083CP%23PBF/LT1083CP%23PBF-ND/888922 [LT1083 Datasheet]
- Note: Appropriate adjustment of maximum output voltage commonly requires several additional electronic components, as specified in voltage regulator datasheet. For the LD1084V regulator used below, the required components are two capacitors (both 10 uF) and two resistors (120 Ω and 1.2 kΩ)
Two (2) x aluminum heat sinks
- Can use scrap aluminum bar or thick sheeting, so long as there is a flat surface for mounting to components
- IMPORTANT: Depending on circuit configuration, it may be necessary to connect diode and voltage regulator to separate, non-contacting heat sinks. (Remember, aluminum conducts electricity!)