May 27, 2015

Simple passive mono/stereo to stereo audio mixer circuit

A while ago I needed a very simple pasive miker to join one stereo and two mono signals together before amplifying them...

There is some mixed information on how to properly connect a mono signal to a stereo input, but most of it uses active mixing.

May 24, 2015

Repair faulty HC-SR04 ultrasonic sensor (solve erratic no-readings problems)

Recently I got some of these cheap sensors from Chinese suppliers, for a workshop I had to teach.
A couple of students reported that their sensors were behaving in an erratic way, sometimes working, then stopping again, the working...
After replacing them with more expensive ones bought at a local store, I decided to try fixing the faulty ones...

Feb 17, 2015