Smart Medicine Cabinet: Build a Sensor That Reminds Patients When to Take Medication
Summary
Michelle Maranowski, PhD, Science Buddies
This science project is based upon the following Clever Scientist award-winning project: Balasingam, Arjun. (2010). Smart Medicine Cabinet: Using Homemade Sensors, a Microcontroller, and a Laptop to Help Patients Take Their Medicines on Time.

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Abstract
Have you ever had to take prescription medicine to get over an illness? To get better, it is important to take the medication in the proper manner and at the proper time. Wouldn't it be cool if there were a tool or piece of automated equipment that held your medicine and reminded you to take it? A tool that would know when you picked up the bottle and took your medicine? Building a smart medicine cabinet is what this science project is all about!Introduction
Making a new tool can be a daunting experience, but if you think about it in pieces, it becomes more manageable. For example, the medicine cabinet should contain some kind of sensor that senses when the medicine bottle has been picked up. It should have a microcontroller that monitors the "pickups," and a computer that takes input from the microcontroller and issues information and alerts.
This science project can be as simple or as involved as you'd like it to be. You could simply demonstrate a sensor that registers when a medicine bottle has been placed on it. Or add to the sensor by attaching a microcontroller that interfaces with a computer—Science Buddies How to Use an Arduino would be a good guide. Then you could write a computer program that displays instructions to the user to remind him or her of the medication schedule. An interface would allow the user to input the medication schedule and signal to the user that it is time to take a medication. Finally, you could add LEDs (light emitting diodes) that act as indicators to the user.
Regardless of how complex you decide to make this science project, the first step is to build an electrical sensor that senses when a medicine bottle has been picked up or placed on it. This sensor should be based on a voltage divider. A voltage divider is a circuit that is used to supply a voltage that is different than the available battery or power supply. Figure 1, below, shows the sensor circuit in two modes. The red squares are conductive metal pads. Figure 1.a. shows the sensor when there is no bottle in place. Here, since there is no connection between the metal pads, current moves through the two resistors (the voltage divider). Figure 1.b. shows the sensor when a bottle is in place. In this case, the bottle bridges the gap and current flow is through the metal pads and the lesser of the two resistors. If you decide to stop with building the electrical sensor, then you will need a digital multimeter to monitor the voltage change (if you need help using a multimeter, check out the Science Buddies resource How to Use a Multimeter).

This magnetic sensor has 2 charged plates seperated by a small gap and connected with a high resistor. When an object, like a pill bottle, is placed on the sensor it bridges the gap between the plates and allows current to flow through so the sensor can know that an object is present. When there is no object to bridge the gap between plates the current has to travel through the resistor and that voltage drop will let the sensor know that there is no object present.
Figure 1. These diagrams illustrate one way the smart medicine cabinet sensors could function. (1.a.) The sensor without the bottle. (1.b.) The sensor with the bottle. (Courtesy of Arjun Balasingam and Wen Phan, 2010.)
If you would like to extend the science project with a microcontroller board, you can learn more about the Arduino Uno, a popular microcontroller, on the Science Buddies How to Use an Arduino page. The tutorial will step you through how to buy and set up an Arduino.
Building a smart medicine cabinet might sound complicated, but remember, every big project can be broken down into smaller more manageable pieces! And this is a project that could certainly be a big help to you or to anyone you know who is taking medication.
Bibliography
- Wikipedia Contributors. (2010, October 4). Voltage Divider. Wikipedia: The Free Encyclopedia. Retrieved October 28, 2010.
- Nave, R. (n.d.). Voltage Divider. Retrieved October 28, 2010.
- Arduino Homepage. (n.d.). Retrieved October 28, 2010, from www.arduino.cc/
If you need clarification on electronics terminology, take a look at Science Buddies' electronics primer. The following is a link to the Introduction. At the bottom of the Introduction are links to other helpful pages.
- Science Buddies. (2010). Electronics Primer: Introduction. Retrieved October 28, 2010.

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