Applications and Implications

Assignment

  • Propose a final project that integrates the range of units covered.

What will it do?

This device will be an open-source and fabricatable pixel-shifting digital microscope. What does this mean is that the microscope will shift the optical sensor (camera) to acquire sequential images of a specimen and then stitch them all together to create a high-resolution image.

Who's done what beforehand?

This project is in fact an attempt to replicate the work done in a paper titled "A portable low-cost long-term live-cell imaging platform for biomedical research and education".
I couldn't get in touch with the team to get the source files to do this so I decided to make it myself.

What materials and components will be required?

ComponentVendorURLImageItem PriceCountPriceNotes
Mechanical Elements
AQS Nema 17 stepper motor with in-built lead screw (4 starts-2mm pitch 8mm dia)AQS
Alternative
MTM BOM$28.392$56.78- Exists in the lab's MTM kit
- Will drive the X-Y mechanism
Gestalt BoardsN/AMTM BOM$15.22$30.4
USB to RS485 Cable 5.90' (1.80m) UnshieldedDigi-KeyLink$301$30
Light Duty Dry-Running Sleeve Bearing, 1/16" Flange Thickness, Nylon, for 3/8" Diameter, 1/2" OD, 3/8" LengthMcMaster-CarrLink$0.598$4.72
Highly Corrosion-Resistant 6063 Aluminum, Anodized Tube, 3/8" OD, 0.070" Wall Thickness, 6 Feet LongMcMaster-CarrLink$9.564$38.24
Optics
12.5x Magnification Eyepiece LensPZOLink$9.011$9.01Salvaged from an old microscope
10x Objective LensPZOLink$491$49
Raspberry Pi 2 Camera ModuleRaspberry PiLink$20.641$20.64
5V Unipolar Stepper MotorLocal MarketLink$4.951$4.95Will control the focus mechanism of the lenses
Control
Raspberry Pi 2 Model BRaspberry PiLink$351$35- Will control the X-Y and focus mechanisms
- Capture and stitch imaged
- Operate the web-interface and data logging
SanDisk SDSDQM-016G-B35 MICROSDHC 16GBSandDiskLink
Link
$71$7
Power
24 Volt Power Supply - 1.1 Amp Single OutputCircuit SpecialistsLink$13.401$20.64
Power Barrel Connector Plug 0.70mm ID (0.028"), 2.35mm OD (0.093") EIAJ-1 Free Hanging (In-Line)Digi-KeyLink$11$1
2.50mm (0.094", 3/32", Sub Mini, Miniature) - Headphone Phone Jack Stereo Connector SolderDigi-KeyLink$1.131$1.13

Where will they come from?

To be able to be replicate the device in Fab labs, the device will use MTM kit that is distributed throughout the Fab Labs Network.

Other parts (optics) can be salvaged from old microscopes or bought through any

How much will it cost?

It will cost approximately $300.

What parts and systems will be made?
What processes will be used?
what tasks need to be completed?
What is the schedule?

SystemTasksProcess
Focus Mechanism
It will responsible for focusing the lenses on the sample and will be controlled from a web interface.
lenses holder and rack and pinionLearn more about microscopy from MicroscopyU
Design and print the mechanism
  • Computer-aided Design
  • 3D Printing
  • Laser Cutting(Computer Controlled Cutting)
Design and fabricate a test mount of the test pattern to discover to test the focus mechanism and discover the height needed for the glass plate.
Stepper motor and driver:
Actuate the focus mechanism
Test current stepper board and modify if needed
  • Electronics Design and Production
  • Embedded Programming
Define stepping needed (rack and pinion and stepping code)
Install Raspbian Jessie Lite and RPi-Cam-Web-Interface for testing
  • Networking and Communication
Test with FTDI and Wi-Fi
Finalize stepper board and mechanism
Web interface
or manual control and feedback
Modify the web interface and test it with FTDI.
  • Interface and Application Programming
Test RaspberryPi Serial communication
Deploy the web interface to the RaspberryPi and test using its GPIO for RS232 communication.
6th of June
X-Y Mechanism
Will shift the camera into a snake-like grid for sequential images capturing.
Shafts holders and stepper mountsDesign and print the mounts, cut the base and test the mechanism manually.
  • Mechanical Design
  • 3D design and Printing
  • CNC Router (Computer Controlled Machining)
Carriage
Will hold the lenses and focus mechanism from the top and the Raspberry pi from the bottom
Design and print the carriage
Machine ControlCreate a virtual machine in pyGestalt and test for the least stepping possible.
  • Machine Design
Port virtual machine to the RaspberryPi and figure out how to use RS-485 from it. If failed use the cable.
Modify the web interface to control the machine
  • Interface and Application Programming
8th of June
Enclosure
Allows the building of another system on the top and the directional light source.
Enclosure for the mechanism in the baseDesign and Fabricate the enclosure
  • Computer-aided Design
  • CNC Router (Computer-controlled Machining)
Glass base for the specimen dish/slide with silicon pads to minimize shakingDesign a mould for the pads and cast them in silicon rubber
  • Molding and Casting
Customizable height control for the light source/height of accessory system
10th of June
Web interface
Will be used by the user to interact with the device from the internet
Web serverRedesign and finalize the user interface
  • Interface and Application Programming
Program the backend for the images stitching and data logging
13th of June

What questions need to be answered?

  • How would the focus mechanism work?
  • How does pyGestalt work and how to create a virtual machine with it?
  • Does Gestalt boards really need RS485 for control or can they be controlled by RS232?
  • Can the Grid stitching plugin work headlessly and would the limited RAM of the raspberry pi handle big a-mount of images?
  • Can the plugin be rewritten in Python and optimized to run on the RaspberryPi?

How will it be evaluated?

  • The quality of stitched images.
  • How easy is it to assemble the kit and operate it.

How will it be evaluated?

  • Can the device be reproduced in any Fab Lab?
  • Are the documentation clear enough for those who which to replicate the work/
  • Have I shown mastery in the processes mentioned?