Created by Lam, Alcaeus H, last modified on Feb 18, 2018

ahlam2 - 110

dhickox2 - 110

jiaminz2 - 120

  1. Introduction

    1. Statement of Purpose

      With the recent rise in popularity of electric skateboards, safety concerns about long-term storage and usability should be addressed. Many DIYers are building their own boards instead of buying commercial solutions in order to spend less. But, this comes at the cost of adding proper safety measures. In our project, we will implement a safe and easy way for the user to disconnect the volatile battery sources that are commonly used. In addition, we will have an onboard led voltage indicator to show battery life, ensuring that the user will be able to avoid unexpected board shutoffs.

    2. Background Research

      Conventional power sources for electric skateboards are LiPo batteries and Li-ion cells. 18650/26650 Li-ion cells are safer to use than LiPo batteries, which are more susceptible to being damaged through improper handling. But due to the steeper cost and generally lighter form factor, LiPo's are most common in budget builds. With either method, the batteries should not be left in a closed circuit with the rest of the components. Battery indicators can often be found on the underside of the board, but whilst riding, a topside led indicator would be most accessible to the rider.

  2. Design Details

    1. Block Diagram / Flow Chart


    2. System Overview

      -12s lipo: this will most likely be a twelve cell lithium polymer battery with a 5 amp hour or greater rating but 18650 lithium-ion cells are not out of consideration since the technology can still be applied to that
      -MOSFET-based kill switch this will be our NAND-based kill switch for satisfying the ECE 110 requirements and it will be an improvement over your usual loop key 
      -VESC-based ESC: this will just be the smart motor driver we intend to use it is one of the best on the market and has several smart communication features we can use to control other function with the Arduino
      -Motor: this is just a motor nothing too fancy, but we won't go anywhere without one 
      -Arduino due: we want an Arduino due for the increased I/O capability and the 32-bit arm cortex increased processing speed, this will allow us to do a lot more with the board for control options and some complex math for speed and battery control
      -mom switch, this will be the momentary switch that allows the board to turn on and off
      - 5v power regulator, this will be the piece used to power the Arduino because an input of 60 volts is not recommended and voltage spices can be much higher than that
      -BMS this will most likely just balance the cells of the battery but if we have time it can be used to map draw stats on the battery and other important analytics to get the most life and performance out of the battery
      -speed wobble control, this is very complex an never has been done before so we do not wish to include this in our main project but it is very possible that we can get it done. the general principle is that skateboards become unstable at high speeds and with a computer controlled system for steering small imperfections in rider balance will not send them into the ground since they can be filtered much better than with traditional mechanical methods the only big challenge is an effective system that can take the weight of a rider and steer smoothly but be no bigger than current truck setups. 

  3. Parts
  4. Possible Challenges

    Managing the voltages/currents that run under this board is going to be a pretty important task. Due to the many different tolerances of our diverse parts, we need to make sure each gets the right amount of power and not short anything. Another possible challenge we could encounter is the consistency of everything working together. Since we have so many parts coming together, we need to make sure every subpart works consistently in order to effectively test our project. Getting the right parts on time while keeping cost low is also a challenge. Many parts of the project we can get for cheap prices could potentially come from China and might not be an option to get because of the incredibly long shipping times. Thus, we will be trading off cost for available parts for a lot of the shopping. Secondly, in order for our project to work, we need to have a working electric skateboard to operate on as well. If we do not have a working skateboard, it would be difficult to test with live situation/speed. 

  5. References

    [1] "Learn How to Build your own E-board", Electric Skateboard Builders Forum, 2018. [Online]. Available: https://www.electric-skateboard.builders/. [Accessed: 18- Feb- 2018].

    [2] T. Youngblood, "Make a Digital Voltmeter Using an Arduino", Allaboutcircuits.com, 2018. [Online]. Available: https://www.allaboutcircuits.com/projects/make-a-digital-voltmeter-using-the-arduino/. [Accessed: 18- Feb- 2018].


Attachments:

unnamed.jpg (image/jpeg)

Comments:

While we have had electric skateboard groups in the past be able to finish within one semester, keep it mind that it will be a decent amount of work. I recommend you try ordering your parts as soon as possible (even this week), and talk with the machine shop as early as possible if you need their help. Just as a reminder, we do collect any components that we fund, so we will be asking for your project back at the end of the semester (some skateboard groups have been under the impression that they get to keep the board at the end of the course). Lastly, I'm guessing that you won't have time for any kind of wobble control, considering that it would require relatively advanced knowledge and a substantial about of time and energy. If you have any questions, come talk to a TA!

Project approved.
Posted by chorn4 at Feb 21, 2018 17:02

Looks good!  Definitely doable if you put in the time.  Like Chris said, make sure you get those part orders in early!
Posted by mnwilso2 at Feb 21, 2018 23:46