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Use a Discarded Pipette Tip Box To Build an LED Matrix

Recently while working in a lab at UCLA after using a box of pipette tips I noticed how close the diameter was to a 5mm LED. So I decided to take a couple of the empty boxes home with me. I tested them out and the LED’s fit like a glove. I couldn’t ask for them to fit any better. The LED’s won’t fall out no matter how hard you shake the plastic and yet you can still use your fingers to pull them out. I haven’t actually made an LED matrix using this plastic, this article simply outlines my thoughts on using the pipette box as an LED matrix template.

LED

The particular pipette boxes I have hold 8 by 12 pipettes. The plastic is extremely rigid and should provide a strong case for an LED matrix. With a Dremel tool or even a box knife and a file these plastic pieces can be easily cut and joined together to make even larger LED matrices. If you leave the tray in the box, you could even use it as a project box with 8x12 LED matrix capabilities.

pipet box and tray

When joining trays together, to make sure multiple units fit together well, I would recommend cutting off the excess plastic as shown in the picture below. This will provide a very clean connection joint with proper spacing so that the combined units look like they belong together. Note that the upper edge and right edge have more plastic cut off than the left edge and bottom edge. This will help keep the spacing between the LEDs at the edges of the matrices (where two trays will meet) even.

LED matrix pipet box with edges off

A heat gun can also be used to heat form the pipette trays to different curvatures as shown in the picture below. The plastic does get really soft and almost liquid like when heated up too much and it doesn't take much extra heat to do it. The LEDs will still fit great when the plastic is bent inward as shown in the picture. LEDs will no longer fit when the plastic is bent outward (not shown). Once cooled down, the tray goes back to being very rigid as expected.

pipet tray bent using heat gun

The pipette trays are not made out of the best plastic. Paint will flake off and glue, if you can get it to stick, will not hold very well. One way to increase the hold of the glue would be to sand down the surfaces to be glued. I would recommend that a frame be built that holds the pipette tray by press fit or screws. This will provide the most secure mounting.

The particular pipette box I used is a set of ninety six 200µL tips from Fisherbrand lab supplies. If you want to find a supply of these empty pipette boxes I would suggest asking university chemistry departments. Sometimes they keep the actual boxes, but most of the time they are just thrown out because so many accumulate. Warning: make sure they are clean, some labs will use dangerous chemicals and biological agents around them so be careful. If you only want to use the pipette tray for your project, the boxes work very well for storing components. They stack easily and they are a good size for holding a range of different items.

LED side shot