We choose this project to solve the problem at queen’s hospital. They have few analog dosing meters at hand right now. Besides this, they usually have calibration drifting which sometimes can be hard to read and give false readings.
We had two prototypes of phototherapy dosing meters, one from Rice university team and another which had been developed by senior polytechnic students. So we had to choose one and improve on it because they all had drawbacks. We choose the poly device after having a thorough analysis of the two devices.
Problems with the Poly design
- The first drawback with the poly design was that it was not using a blue light filter, hence giving false readings as it was prone to ambient light.
- The relationship which was used in the arduino program was not correct
Objective
So basically our main focus was to develop a low cost phototherapy dosing meter that suffers no calibration drifting, more accurate and portable. This partly involved changing the circuitry because we used a solar cell instead of an LDR that was used by the poly students. We used the Arduino Uno as a microprocessor and we coded it in C language.
Operation: The sensor will be covered by a blue light filter thereby measuring only the blue light from the Bili lights. Then it will pass a current through the circuit dropping a voltage across a resistor. This voltage then fed to a low pass filter, allowing less than 4 kHz to pass through. From there on, the output is fed into the arduino for processing. The arduino outputs the result on then LCD.
