Crafting Material Interfaces

So I wanted to see if I can make something useful, and also challenge myself in terms what I had not done before (I must say a great portion of this class has already done that).

The aim of my project is to create a high blood pressure sensor, such that at a certain ‘danger’ mark, an LED will light, and a buzzing sound will be produced. I thought of combining a couple of existing devices, in particular a mercury sphygmomanometer as well as a metal detector to create this new sensor.

In a mercury sphygmomanometer, mercury rises up a glass gauge according to the blood pressure measured on a patient’s arm. The idea is to attach a metal detector that functions as an alarm or a warning to a certain mercury mark. As the reading for hypertension is 160mmHg, the detector is attached here.

Here are the parts that I was working with:

On the bottom left is the board and the metal rod that will form the bulk of the metal detector, and moving to the left I have laid out the various capacitors, resistors and diodes. The bottom right is the solder, which will turn out to be the trickiest part of this project.

Here is the underside to the board pre-solder. For a neophyte like me, this is intensely intimidating!

And this is how it looks when it is done!

This is how the metal detector component looks when it is done. The little red dot is the LED light, and the round black tack next to it is the buzzer. The aluminum dial allows me to adjust the sensitivity of the metal detector.

Unfortunately, the metal detector doesn’t work, I am not sure exactly why. The instructions warn me that the most common problem is due to the circuit breaking or shorting from poor soldering, so that could be it.

But the idea is to attach this metal detector to the sphygmomanometer, like so: