I made a test using the Dettol plunger pump to deliver water to a becker. Using a balance, I determined the volume delivered. You can see the unmount process from my last post Dettol No Touch Tearsdown.
To control it, I cut the infrared led and I connected the anode of the LED to the emitter of a BC548 transistor and the cathode of the LED to the ground. The transistor was pulled-up to the 5V with a resistor of 510 ohm connected to the collector. To switch the transistor, I used a push-button pulled-up to 5V. The base of the transistor was connected between the resistor and the push-button. So, when I press the button, I simulate the hand cutting the infrared light beam. Only the supply power of the Arduino board was used with a prototype shield from Sparkfun. I did not change the electronic circuit inside of the pump because I wanted something simple to be controlled.
|De Dettol infrared webcam|
To confirm if the system was working, I used my webcam modified without the IR filter.
|Dettol infrared webcam|
The next video shows in detail the electronic parts and the wire that holds the IR LED.
The plastic parts that contact with solution is made of PP. It make it acceptable to acids and bases.
I used crystal PVC tubes of 1/8" and a 2cm of crystal PVC tube to make the connection with the inlet of the pump and two clamps (yellow and green).
A balance with 0.1g of precision was used to this test. Considering the density of the water is 1g/mL, the volume add each time that I press the button is 1.5mL. It is a huge volume for a fine titration. However, this pump could be useful for big volumes. One possible application could be use two pumps (one with an acid and other one with a base) to mount a pH-stat: a device that dose acid and base to maintain the pH constant.
If you have a suggestion, open the discussion.