LTOst's breadboard bomb (not really)

It’s a prop bomb countdown timer built on a D1 Mini (ESP8266).
Hardware: D1 Mini, SPI OLED display, passive buzzer, 2 LEDs, and a relay module powered from an external 5V supply.
What it does: Counts down from 5 to 0 on the OLED with increasing beep pitch and blinking LEDs each tick. At 0 it triggers a relay, then runs a “boom” sequence — rapid LED strobing, a siren wail from the buzzer, and a “* BOOM * (not really)” screen.
The journey to get it working:
∙ Started with I²C OLED, swapped to SPI
∙ Fixed the display.begin() call (wrong init constant for SPI mode)
∙ Debugged the relay through several layers — wiring, voltage, current, timing — eventually isolating it to a code timing issue where the relay fired too late due to blocking tone_play loops and a duplicate digitalWrite in two places

yt: https://youtu.be/9-CtBhBM-d8?is=VOagViKt7MRDBosk

Woken: https://wokwi.com/projects/460665369926308865

This project uses AI

Used AI for description of the project, finding the right modules, all of the Wokwi, learning how to use modules, discussion of hardware and readme

Demo Repository

Shipped this project!

The thing i built a countdown timer prop bomb. It counts down displays it on a screen as well as LED’s blinking and a speaker playing (optionally you can use the relay which triggers when the timer hits 0). The hardest part was to get the relay to work since i used a WEMOS d1 mini (esp8266) and it didn’t quite have enough power to use the relay and all the other digital ports. I fixed this by using an external power supply for the relay, i also added a manual trigger, but removed it before the completion of the project.

0 Followers

Shipped this project!