This is a simple pace-maker project that utilizes an ATtiny85. It is only halfway finished at the moment.

Step 1: Acquire the Necessary Sensors

Start by acquiring a vibration motor and the Makerfocus MAX30102 heartrate sensor, and connecting them to an Arduino Uno. Google pinouts for each part to get an idea of how to connect them.

Step 2: Add the Required Library

Add the Sparkfun 3010X library as shown in the screenshot. We will be using a part of the code from the heartrate reading example.

Step 3: Add Our Custom Code

The screenshots show the added code in addition to the heartrate library code.

Increase the Rate Size to 10 to obtain more stable average heart rate readings from the sensor;

targetPace sets the pace at which the LED blinks and the vibration motor actuates;

threshold sets the maximum allowed heartrate before stepping down the pace;

lowestPace sets the lowest allowed pace;

limitStop sets the rate at which pace decreases when the heartrate is over the threshold.

Step 4: Miniaturization

To miniaturize the Uno into an ATtiny85, prepare a power management board and a battery. Upload the program unto the ATtiny85 by following the Arduino Uno as ISP method.

* Remember to remove any codes associated with the serial monitor, otherwise ATtiny85 would not function properly.