The Count-a-Drop Pipettor

Count-A-Drop Pipettor - 

Precision Droplets, Counted Automatically

For lab nerds, biohackers, makers, or anyone tired of losing track of pipetted drops.

What It Does

This is the scientific sibling of the Count-A-Click Pen - reimagined as a droplet-counting pipettor. It clicks and counts every drop you pipette, combining mechanical satisfaction with lab-grade usefulness.

How It Works

• Insert a standard 5 ml pipette (available on Amazon)
• Press the plunger through the side cutout to draw in liquid
• Adjust the stroke length using the fine-tuning nut:
  • Set it to release exactly one droplet per click
  • Or adjust up to approximately ~0.5 ml per click
  • Each click includes a small stroke overrun, allowing the release of a clean, complete droplet every time
• A built-in lever releases pressure from the push mechanism:
  • Use it after finishing, when the pipette is empty, or if you want to refill
• Each click both dispenses and counts-ensuring consistent dosage and perfect tracking

Assembly Requirements

• 1x Bambu 2x40 mm dowel pin
• 1x Bambu 2x30 mm dowel pin
• 2x small compression springs (0.3x3x10 mm)
• 1x standard 5 ml pipette Amazon Link
• Tilt plates printed in ABS-GF for proper mechanical function under load

Assembly Instructions

1. Counter Mechanism Assembly

Follow the exploded view and refer to the assembly video to put together the counter unit.
 

2. Pipettor Module Assembly / Upgrade

If upgrading from the Count-A-Click Pen, the main structure stays largely the same. Install the pipette module in place of the pen insert and connect the stroke adjuster and reset lever accordingly.
Detailed positioning can be seen in the pipettor-specific exploded view and video.

Things to Keep in Mind

• Not an easy print: This project requires precision and patience.
• Clean plate: Ensure your build plate is spotless for good adhesion. Using a supertack plate can help.
• Small parts:  These are very small, pushing the limits of a 0.4 mm nozzle.
• Support residue: It's crucial to remove all support residue to ensure proper assembly.
• Challenging assembly: Due to the small parts, putting everything together can be tricky.
• Tolerances: Depending on the filament and your printer, tolerances might vary.
• Material: The pen prints in PLA, with some parts using "support for PLA" filament as an interface.
• Lubrication: Moving parts only on the Counter Assembly should be lubed (e.g., Bambu lubricant oil).
• Do not apply lubrication to the pipette section
• Assembly: Gears must be assembled in their exact intended positions to function properly
• Ensure the counter mechanism runs smoothly before attaching the pipette section
• Changing print profile parameters can affect fit and functionality

Use Cases

• Repetitive droplet dispensing in labs or workshops
• Small-scale chemistry or bio experiments
• Teaching, prototyping, or liquid-based creative projects
• Enjoying the tactile feel of a mechanical click while dosing precisely

Disclaimer

This is not a calibrated lab-grade instrument, but a functional prototype intended for experimental, educational, and hobby use.
Additional notes and points will be added based on community feedback.
If there's enough interest, a refined version could be developed for more reliable, long-term use in practical settings.

Count-A-Drop Pipettor - Every drop, accounted for.

Click. Count. Dispense. Done.