This BYOC was designed to achieve one of my goals I had set upon joining the ISAC SRL EL program. The purpose of the BYOC is to act as an additional aid to spark interest when teaching cytometry to students. It has been designed to be affordable ($500-$1500), 3D printable and fun to build. I have included the build list, instructions, notes and highlight there are many opportunities for improvement/modification (I can attest to this with my experience over the last 6 years).
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- The laser interception point as of 2022 has been fixed at 127mm from the base. This 'fixing' allows for a simpler setup and easier modifications.
- Using the relatively affordable 'blackridge' air regulator from Supercheap auto, with a 0.1um PES filter in line, dial 3 full rotations and then dial back a 1/2 rotation of the air pressure regulator valve for this project. This provides approximately 2-3psi that is hard to observe on the blackridge air regulator.
- When focusing the laser it is important to focus it so that there are no striations seen when centered. Striations indicate a focal point either behind or infront of the stream. An optimal focus will have striations briefly when aligning the laser stream and it is crossing the edges but will result in no striations when centered.
- The microscope used in this project is a modified kids toy without any optical filters. To view the core stream interception point ensure the microscope is angled so that stray laser speckle does not overwhelm the scope.
- The testing rig LED can be run from an external pulse generator. >1000 pulses per second work well for the preamplifier circuit design. Try increasing the speed of the flash if there is a negative pulse.
- Photodiode - 9x9V for Photodiodes or none!
- APD - 9x9V + Polulu fine control. 86V saturates APD, 83V just detects, 85 less.
Notes - other references
mmHg to PSI
**Divide by 51.715 to obtain PSI**
| mmHg | PSI |
| 0 | 0 |
| 20 | 0.386735 |
| 40 | 0.77347 |
| 60 | 1.160205 |
| 80 | 1.54694 |
| 100 | 1.933675 |
| 120 | 2.32041 |
| 140 | 2.707145 |
| 160 | 3.09388 |
| 180 | 3.480615 |
| 200 | 3.86735 |
| 220 | 4.254085 |
| 240 | 4.64082 |
| 260 | 5.027555 |
| 280 | 5.41429 |
| 300 | 5.801025 |
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| Item | Qty | Purpose | Sources | Cost ($AUD) | Notes | Image |
|---|---|---|---|---|---|---|
| 600x600 tile | 1 | base | Local tile supplier | Free (tell them what you are making) | Aim for a free marble tile  | |
| 600x600 steel sheet | 1 | build platform | Bunnings (Sydney) | $26 | Ensure it is magnetic. Thickness does not matter, thinner normally means cheaper. I recommend sign steel. Have some fun and wobble it ;p | |
| 0.3M7TIA gear | 2 | holds HPLC in the centre of luer lock | Aliexpress | <$5 for 20 | https://www.aliexpress.com/item/33000449925.html?spm=a2g0s.9042311.0.0.86a84c4dqSRqUr |  |
| 450 extension springs | 19 (2 detectors), additional 6 per detector | provides pulling force to mirror, laser, lenses | Bolts & Industrial (Sydney) Century Springs (US) | $4 | We need to buy it from a reseller. Spring Catalogue: https://www.centurysprings.com.au/products/prod_catalogue.htm Can also buy about 10x cheaper from ebay. |
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| M3 socket screw | bag | used as screws to put the whole thing together | RS components or ebay | |||
| M3 nut | bag | Ensure outside dimensions are 5.5mmx5.5mm | RS components | $13.80 | RS PRO, M3 5.5mm Steel Square Nuts, Bright Zinc Plated Finish 837-262 |
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| 25mmx25mm optics | 2-3 | focus light onto detector from intercept point | Edmund optic | $52.80 | Stock #32-490 https://www.edmundoptics.com.au/p/25mm-dia-x-25mm-fl-mgfsub2sub-coated-double-convex-lens/2375/ | |
| 5mmx25mm optics | 1 | focus laser light onto stream | Edmund optic | $61.50 | Stock No. #87-913 https://www.edmundoptics.com.au/p/50mm-dia-x-250mm-fl-mgfsub2sub-coated-plano-convex-lens/30185/ | |
| 100um nozzle | 1 | eject stream | Intertronics or FISNAR | 38 pounds | https://www.intertronics.co.uk/product/preci-tip-precision-dispensing-tips/ IDMSPREC-M100-NS | |
| Luer lock connectors and 1/4inch BSP to barb fittings | 1 | to connect to nozzle | Bunnings & Kinesis Australia & USA KENT | I will need to seperate this column a bit more - information will be provided during the workshop. |  | |
| 30mm x 10mmx 3mm | 20 | mount items | Ebay | $18 | 20pcs N50 Strong Block Cuboid Rare Earth Neodymium Magnets 30mm x 10mm x 3mm | |
| Circular magnet | To mount APD instead of photodiode |  | ||||
| 20L Drum | 2 | used to create a vacuum | recycle bin | free | to make see instructions | |
| Regulator | 2 | adjust pressures | supercheap auto | $30 each or $30 for 2 | https://www.supercheapauto.com.au/p/blackridge-air-regulator/340078.html or | |
| APD or Photodiode | 1 minumum | convert photons to current | many sources including old instruments | $15 each | APDs used are AD500-8 TO52 package or BNC photodiode package | |
| Laser 532nm (or equivalent) | 1 | AIXIZ lasers | $38.50USD | https://www.aixiz.store/product-page/532nm-5-25mw-adjustable-power-3vdc-line-cross-attachable-ad-532-25adj | ||
| Electronics shopping list (per detector) | ||||||
| Prototyping board | 1 | $8.19 | ||||
| RJ45 breakout | 2 | $1.33 | https://core-electronics.com.au/breakout-board-for-rj45.html |  | ||
| LT1364CN8#PBF-ND | 2 | opamp used for I>V and for amplification | DIGIKEY | #13.73 each | https://www.digikey.com/product-detail/en/linear-technology-analog-devices/LT1364CN8-PBF/LT1364CN8-PBF-ND/891887 | |
| Cat7 RJ45 cable | 1 | $8 | Amazon/Ebay | |||
| Adjustable 10^5 25 turn resistor | <$1 | Jaycar (generic electronics parts store) | ||||
| Adjustable 10^3 25 turn resistor | <$1 | Jaycar (generic electronics parts store) | ||||
| 1N4148 diodes | 4 | <$1 | Jaycar (generic electronics parts store) | |||
| 10pF ceramic capacitors | 2 | <$1 | Jaycar (generic electronics parts store) | |||
| 10K resistor (1% tolerance) | 3 | <$1 | Jaycar (generic electronics parts store) | |||
| 100K resistor | 2 | <$1 | Jaycar (generic electronics parts store) | |||
| 1K resistor | 1 | <$1 | Jaycar (generic electronics parts store) | |||
| 22K resistor | 1 | <$1 | Jaycar (generic electronics parts store) | |||
| 0.22uF ceramic cap | 1 | <$1 | Jaycar (generic electronics parts store) | |||
| 1uF ceramic cap | 1 | <$1 | Jaycar (generic electronics parts store) | |||
| 2 pin molex pcb header 2.54mm pitch | 1 | $0.20 | https://www.jaycar.com.au/2-pin-0-1-straight-locking-header-2-54-pitch-single/p/HM3412 | |||
| 3pin molex header female 2.54mm pitch | 1 | used to connect to APD | $0.55 | https://www.jaycar.com.au/3-pin-0-1-header-with-crimp-pins-2-54-pitch/p/HM3403 |  | |
| hookup wire and crimpers | $0 | Spares in every household | ||||
| 9V battery connectors | 4 | buy different types of connectors to ensure flat 80-90V power supply | $1.40 | |||
| 8 pin IC housing | 2 | mount for IC chips | $1.25 | https://www.jaycar.com.au/8-pin-gold-insert-machined-pin-ic-socket/p/PI6452 | ||
| 4 or 6 way DIP switch | 1 | used to turn power on / off | $1.65 | https://www.altronics.com.au/p/s3050-4-way-dip-switch/ | ||
| shielded RJ45 port | 2 | needed to suppress noise | $1.75 | https://www.altronics.com.au/p/p1538-oupiin-8p8c-rj45-modular-socket-shielded-pcb-mount/ | ||
| Differential pressure regulation | ||||||
| pressure transducer - 24PCAFA6D | 1 | accurate pressure differential between sample/flow cell | Element14 | $61.89 | 0-1psi - 0-45mV - 2002508.pdf |  |
| OPAMP - breakout for pressure transducer | 1 | simple 2 stage amplification of 100 | Core electronics | $9.90 | BOB-09816 100x gain |  |
| LCD keypad | 1 | pressure output monitor | Core electronics | $16.50 | https://core-electronics.com.au/lcd-keypad-shield-for-arduino.html DFR0009 |  |
| arduino and case | 1 | arduino uno | Core electronics | $39.95 + $4.70 | CE05634 A000066 | |
| Aluminum laser mount and heat sink | 1 | holds and cools the laser | Aixiz laser supplies | USD$3.95 | 12X30mm aluminum mount for AixiZ 12X30mm units[AIX-ALM-MT-1] |  |
| 6mm nuts | many | mounts with 3mm threads | RS components | $12.23 pkt of 100 | RS PRO, M3 5.5mm Steel Square Nuts, Bright Zinc Plated Finish 837-262 |
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| Molex 2 way connector and crimp | 1x for laser power source | Allowing the disconnection renders the laser and power supply modular. | RS components |
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| Cable ties | many | Need I say more | 100mm x 2.5mm |
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| Polulu fine control stepup/down voltage regluator | 1 per APD detector | 9V batteries are coarse adjustment - this gets you finer control | core electronics | $27.15 | https://www.pololu.com/product/2869 The output voltage of the regulator is controlled with a 12-turn precision potentiometer. Turning the potentiometer clockwise increases the output voltage, and it can be measured using a multimeter. |  |
Instructions
Setting up the laser
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