I do a lot of trail riding, and being a steward of good riding etiquette, I use a digital horn (more of a “beeper”) to alert hikers when I’m approaching. Most are appreciative of the gesture, and there are always some who seem to think trails are for hiking only. So, a high pitched loud chirp does the trick and also makes for a good laugh as some think it’s their phones or strange birds. Point is, it is loud and gives ample notice. I previously had an RBBell which finally gave up the ghost. As there’s nothing on the market like it, I decided to break out the skills and make my own flavour of it. Read on to see how I used a 110dB piezo buzzer, 555 timer, a cap, some resistors to make it so!