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.
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.
Component | Vendor | URL | Image | Item Price | Count | Price | Notes |
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Mechanical Elements | |||||||
AQS Nema 17 stepper motor with in-built lead screw (4 starts-2mm pitch 8mm dia) | AQS Alternative | MTM BOM | $28.39 | 2 | $56.78 | - Exists in the lab's MTM kit - Will drive the X-Y mechanism | |
Gestalt Boards | N/A | MTM BOM | $15.2 | 2 | $30.4 | ||
USB to RS485 Cable 5.90' (1.80m) Unshielded | Digi-Key | Link | $30 | 1 | $30 | ||
Light Duty Dry-Running Sleeve Bearing, 1/16" Flange Thickness, Nylon, for 3/8" Diameter, 1/2" OD, 3/8" Length | McMaster-Carr | Link | $0.59 | 8 | $4.72 | ||
Highly Corrosion-Resistant 6063 Aluminum, Anodized Tube, 3/8" OD, 0.070" Wall Thickness, 6 Feet Long | McMaster-Carr | Link | $9.56 | 4 | $38.24 | ||
Optics | |||||||
12.5x Magnification Eyepiece Lens | PZO | Link | $9.01 | 1 | $9.01 | Salvaged from an old microscope | |
10x Objective Lens | PZO | Link | $49 | 1 | $49 | ||
Raspberry Pi 2 Camera Module | Raspberry Pi | Link | $20.64 | 1 | $20.64 | ||
5V Unipolar Stepper Motor | Local Market | Link | $4.95 | 1 | $4.95 | Will control the focus mechanism of the lenses | |
Control | |||||||
Raspberry Pi 2 Model B | Raspberry Pi | Link | $35 | 1 | $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 16GB | SandDisk | Link Link | $7 | 1 | $7 | ||
Power | |||||||
24 Volt Power Supply - 1.1 Amp Single Output | Circuit Specialists | Link | $13.40 | 1 | $20.64 | ||
Power Barrel Connector Plug 0.70mm ID (0.028"), 2.35mm OD (0.093") EIAJ-1 Free Hanging (In-Line) | Digi-Key | Link | $1 | 1 | $1 | ||
2.50mm (0.094", 3/32", Sub Mini, Miniature) - Headphone Phone Jack Stereo Connector Solder | Digi-Key | Link | $1.13 | 1 | $1.13 |
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
It will cost approximately $300.
System | Tasks | Process | ||
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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 pinion | Learn more about microscopy from MicroscopyU | ||
Design and print the mechanism |
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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 |
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Define stepping needed (rack and pinion and stepping code) | ||||
Install Raspbian Jessie Lite and RPi-Cam-Web-Interface for testing |
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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. |
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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 mounts | Design and print the mounts, cut the base and test the mechanism manually. |
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Carriage Will hold the lenses and focus mechanism from the top and the Raspberry pi from the bottom | Design and print the carriage | |||
Machine Control | Create a virtual machine in pyGestalt and test for the least stepping possible. |
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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 |
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8th of June | ||||
Enclosure Allows the building of another system on the top and the directional light source. | Enclosure for the mechanism in the base | Design and Fabricate the enclosure |
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Glass base for the specimen dish/slide with silicon pads to minimize shaking | Design a mould for the pads and cast them in silicon rubber |
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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 server | Redesign and finalize the user interface |
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Program the backend for the images stitching and data logging | ||||
13th of June |