You’ve probably heard that caffeine is a drug. That is true and it is possible to overdose on caffeine and die. Heathline reports that a lethal dose of caffeine is around 10 grams. But a typical cup of coffee only contains around 100-200 milligrams of caffeine, so you’d have to drink at least 50 cups to reach a lethal amount. However, some coffee, such as from Death Wish Coffee Co, contains much more caffeine and that makes it easier to overdose. With that in mind, Michael Pick used an Arduino to build a custom coffee machine.

According to Pick, Death Wish coffee contains up to 728mg of caffeine per 12oz cup. Theoretically, that makes it possible for a person to drink enough coffee to overdose on caffeine. There aren’t many people out there who drink that much coffee, so this project is entirely tongue-in-cheek. But it is still fun to see an actual progress meter counting up to your death with every cup of joe that you brew. That is exactly what Pick’s coffee machine does. It tracks each cup of coffee brewed and displays the caffeine overdose progress on a small OLED screen attached to the front of the coffee machine.

Pick started with a basic Keurig K-Express coffee machine that features single-button operation. He connected an Arduino Uno to that button to count each press. The Arduino’s sketch tracks the number of button presses and calculates the “Death Percentage,” which is based on 20 cups of 8oz each. It then shows that percentage on the OLED. Pick mounted the Arduino inside the Keurig’s enclosure and 3D-printed a custom front cover that houses the display. With this hardware, Pick now has a coffee machine that will tell him if he is going to die.