See this BOM on FindChips if you are building the easy breadboard prototype version.

The latest version of the Arduino IDE is recommended. Get it from arduino.cc.

Install git and clone the GitHub repository by issuing git clone <a target="_blank" rel="noopener noreferrer" href="https://github.com/LightningStalker/Med-Timer.git">https://github.com/LightningStalker/Med-Timer.git</a> from within your sketchbook folder or download the ZIP file from the GitHub. Either way, you should end up with a folder named Med-Timer inside your sketchbook folder. The sketchbook folder is a directory named Arduino, either in your home directory on Linux machines, or inside the Documents folder on Windows and Mac OS.

Now start up Arduino IDE and Med-Timer should appear in the Sketchbook in the File menu. If not, just go to File -> Open and locate the place where you cloned/unzipped it in the step above. Open up Med-Timer.ino or click on Med-Timerin the sketchbook. Customize the timers and alerts under where it says morning dose. This should be fairly obvious if you have experience with Arduino sketches. If not, arduino.cc has everything you need to get started. See more about this further down in the Customization section.

The rest is obvious if you're familiar with Arduino. Plug in the Arduino USB and it should be automatically detected in Arduino IDE. Select your board under Tools -> Board and click the blue arrow ➡ button to upload or Sketch -> Upload and your timer should be ready.

Plug the Arduino into a breadboard and attach the buzzer to A4 and GND. Attach a switch to A12 and GND.

All input and output pins are interchangeable, of course, by modifying the appropriate lines of code. Pin D13 is used by the Arduino's onboard LED, however and use of other pins is recommended.

The time delay hours(), minutes(), and seconds() wrapper functions for the delay() function are provided for convenience. Use them to set intervals between doses.

Sometimes 2 or more different medicines are taken at differing intervals. The error variable has been provided for this purpose. The alert() function returns an unsigned long of how many seconds it has been running. In case the alert is not noticed for several minutes, this accumulating time value may be stored in error and subtracted from subsequent calls to time delay functions.

In the example POC, 2 medicines are taken in the morning at the same time before starting the timer. One is to be taken every 4 hours, and another to be taken once more again in 5 hours. If after running the 4 hour timer and calling alert(), that alert is then not noticed for 30 minutes, the 5 hour medicine will be delayed by that 30 minutes if a 1 hour timer is simply slated to run after the call to alert(). Thus, storing the runTime of alert() in error and subtracting it from the delay of the next timer ensures that the 5 hour medicine is indeed taken at the 5 hour mark.

The Timer library eliminates this problem and offers increased simplicity, possibly at the price of increased memory usage.