Electric Nickel Board

Project Description

We intend to build an electric two-wheel scooter with a 3D printed chassis. The scooter will ride on 4.9” diameter skateboard wheels and the drive shaft will be run by a 12 V high torque motor. The scooter will have a contact braking system in which friction slows down the drive wheel. The motor and 12 V battery will be hooked to a variable speed controller so as to be able to accelerate the scooter to a desired speed. If we have time at the end of the semester, we would like to add an infrared proximity sensor as a means for collision avoidance. The sensor would allow us to compute the distance of objects in front of the scooter and if the rider is approaching an object or person, a speaker on the bottom of the scooter can sound a tone to warn the driver.

Overview

We intend to build an electric two-wheel scooter powered by a 12 V brushed DC motor. The scooter will have a speed controller to allow the user to accelerate to a desired speed. The main handle bar shaft will be able to pivot so that the user can manually vary the angle of the front wheel to steer the scooter. The scooter will have a brake on the back wheel so as to allow the rider to reduce speed through contact friction between the wheel and brake. Power will be provided by a 7 AH battery which allows the rider a considerable travel distance on a charge. The battery will be a Lead Acid battery and is rechargeable via an AC to DC 12 V wall charger.

Objectives

A successful scooter will be durable and able to withstand the weight of an average adult and be able to accelerate the rider to a reasonable speed. The speed controller should allow the user to choose the speed at which to ride and the brake should allow the user to stop in a reasonable distance. The battery should be able to sustain the scooter for a reasonable amount of time and the scooter should be able to power on and off so that it preserves battery when not in use.

Challenges

The main challenge of this project is going to be creating the CAD files to 3D print all of the parts so that they fit together. The printing of the parts will be challenging as the tolerances are quite small and we may need to print parts more than once in order to create a functional part. Also, we need to schedule enough time to print all of the parts as well as to have enough time to reprint them if necessary. The handlebar mount and front wheel mount will be difficult to design and will have to be sturdy enough to withstand the weight of a rider. User safety is an important factor as well as ease of use. Therefore, we need a means of acceleration that will stop accelerating the scooter in case the rider falls off. We need to isolate the battery and circuitry to minimize user injury by electronic failures. In addition, the break should operate smoothly so the rider can stop abruptly if necessary to avoid obstacles. The limited budget of $150 is challenging as the motor itself costs $50. Therefore, we had to pick and choose only essential parts for the operation of the scooter. Once built, the operation cost of the scooter should be relatively low with only the occasional need to recharge the battery.

Team Members

Ari Cotler, Serra Erdamar, Andrew O'Sullivan (TA)

Budget

• AmpFlow M27-150-P Brushed Electric Motor, at $49.66 at Amazon (link)
  • The motor will power the scooter.

• RioRand Upgraded 6V-90V 15A DC Motor Pump Speed Controller, at $10.99 on Amazon (link)
  • Speed controller will allow user to control speed of scooter manually.

• Skate Wheel - 4.90(Blue)x2, at $9.98 on Sparkfun (link)
  • Skate wheels will allow scooter to move.

• Skate Wheel Adapter - Shaft Connection, at $5.99 on Sparkfun (link)
  • This adapter will allow us to attach the back wheel to the shaft of the scooter.

• Ball Bearing - Non-Flanged, at $1.99 on Sparkfun (link)
  • The ball bearing will help and allow the front wheel to roll smoothly.

• Flanged Standoff A, at $2.95 on Sparkfun (link)
  • Used to attach front skate wheel.

• Shaft - Solid, at $2.09 on Sparkfun (link)
  • Used to connect handle bars to the scooter base.

• BESTORQ 240-3M-15 3M Timing Belt, Rubber, 240 mm Outside Circumference, 15 mm Width, 3 mm Pitch, 80 Teeth, at $4.23 on Amazon (link)
  • Needed to drive the back pulley and shaft.

• 12 V Lead Acid Battery 7AH, at $16.99 on Amazon (link)
  • Battery needed to power scooter's motor.

• Timing Pulley, at $13.99 on Amazon (link)
  • Allows the Back shaft to interface with the pulley

• Sparkfun shipping, $6.78
  • Shipping price

• Toggle Switch, at $1.95 on Sparkfun (link)
  • Used to turn scooter on and off.

• Steel Sheet Metal Screw, Zinc Plated, Pan Head, Phillips Drive, Type AB, #6-20 Thread Size, 1" Length (Pack of 100), at $2.53 on Amazon (link)
  • For fastening

• Steel Sheet Metal Screw, Black Oxide Finish, Undercut 82 degrees Flat Head, Phillips Drive, Type AB, #6-20 Thread Size, 1/4" Length (Pack of 100), at $3.83 on Amazon (link)
  • For fastening

• The Hillman Group 7731 Round Head Combo Machine Screw with Nut, at $4.94 on Amazon (link)
  • For fastening the brake lever

• Irwin Tools 4935635 Black Oxide Hex Shank Drill Bit, 7/64-Inch, at $3.49 on Amazon (link)
  • For drilling holes

• TOTAL = $141.69

Gantt Chart