Week 16: Applications and Implications
Assignments
The assigments for this week are:Propose a final project masterpiece that integrates the range of units covered.
Final Project: Flatpack Personal mobility device (PMD)
My proposal for the final project is to build a flatpack PMD. The details are documented in the final project page.What Will It Do?
The flatpack PMD will be a simple vehicle that will be able to travel over short distance in urban settings (I.e., along pavement and roads).Who’s Done What Beforehand
Commercially, there are a huge variety of PMDs, including electric scooters, electric bicycles, and electric wheelchairs (which falls into another category of Personal Mobility Aid, or PMA). There had also been many DIY projects, mainly with the aim of bringing the cost down. Simpler projects involved adding new seats or chassis to available products , while more elaborate projects which build the electric wheelchairs from design and stock material are available on instructable or their own website.
Photo from hackoday
Photo from Instructables
Photo from Open Wheelchair Foundation Within Fab Academy and Centre of Bits and Atom, there are a number of projects related to mobility, such as:
skateboard project by Jonathan Abasolo:
Strobotby Omar Al Dajani:
User tracking trolley by Theo Gautier:
Press Fit Go Kart by Andrew Mao:
What Did I Design
I had designed the following: Chassis of the PMDThe original idea was to have a box shape as the chassis, so that there will be a storage space. However, after taking into account the measurements and prioritizing compactness of the PMD, I decided to forgo the storage space and instead opted for a stool design.
Throttle system
The throttle system consist of two components. The first of which is the circuit board that I designed:
The other component will be a foot control connected to the circuit board as the input device.
Wheel mount
The wheel mount was designed and 3D printed to fit to the chassis.
What materials and components were used
These are the material purchased specifically for the project:| Part | Details | Source | Quantity | Unit Price (USD) | Subtotal |
|---|---|---|---|---|---|
| Brushless hub motor wheel | Dia. 10 inch, 36V, 250W | Taobao | 2 | $27.12 | $54.24 |
| Motor controller | 36-48V, 350W | Taobao | 2 | $5.38 | $10.76 |
| Lithium ion battery | 36V, 12Ah, including casing and charger | local source | 1 | $250.00 | $250.00 |
| Motor controller | 36-48V, 350W | Taobao | 2 | $5.38 | $10.76 |
| LM2596 Power Converter Module | DC 2.5-40V to 1.25-37V | Shopee | 1 | $1.67 | $1.67 |
| Part | Details | Quantity |
|---|---|---|
| Plywood, 18mm thickness, min. 650mm x 450mm | Used material | 1 |
| Plywood, 15mm thickness, min. 500mm x 500mm | Used material | 4 |
| PLA filament | - | 120g |
| M6 x 30mm Screws | - | 16 |
| M6 nuts and washers | - | 16 |
| Misc. items | Wire connector, crimp pins, crimp pins housings, etc. | various amount |
| Part | Details | Quantity |
|---|---|---|
| FR1 board/td> | - | Min. 30mm x 40mm |
| Attiny412, SMD | - | 1 |
| Reistor, SMD, 1206 | 1K Ohm | 1 |
| LED, SMD, red | SMD, 1206 | 1 |
| Capacitor, SMD, 1206 | 1uF | 1 |
| Header pin | 2.54mm, pitch horizontal | 1x 5 pins, 1 x 6 pins |
What Processes Will Be Used
Additive:3D printing for the wheel mounts. Subtractive:
Large format CNC milling for the chassis.
PCB Milling for circuit board. Programming:
Embdedded programming using Arduino IDE
How Will The Project Be Evaluated
The flatpack PMD, as a basic personal transporter, should at the minimum be able to be ride on and be navigated by the rider. As such, the PMD should be able to perform the following tasks:- Able to hold an average person's weight
- Able to move forward
- Able to turn left and right according to the user's control
- The speed of the PMD can be controlled electronically