How Can I Build an Easy Weight-Activated On/Off Switch?

I remember using pressure-sensitive strips under rugs when I worked at an alarm company. You could try using two strips of thin aluminum spaced apart and place them under the dispenser. When enough weight is applied, they touch and trigger the switch. It's a simple method that might work for your project!

You’ll definitely need a switch and possibly a spring for the weight activation, but keep in mind that the weight of a soap bar may be too low for some systems to work effectively. Light or capacitive sensors might be a better option if that becomes a problem. Good luck!

A micro switch with a 3-inch lever could also work well for your setup. It’s pretty straightforward and can be activated with a little weight. Just make sure it’s sensitive enough for the amount of soap you have!

For a weight-activated switch, you could go electronic by using load cells with an Arduino to monitor the weight. When the weight drops below a certain threshold, it'll trigger the switch. If you prefer a mechanical approach, you could try a lever or pulley system that activates when the soap weight reaches a low point. Both methods can be effective!