Yes, there is a chance to realize one simple non-arduino project of a forgetful plant waterer! If you are looking for this option, digital output of the module must be linked to the little circuit ...

The circuit oscillates at 91 kHz with a 48% duty cycle. You can use almost any common NPN or PNP transistors, as long as they have moderate forward-current gain of 50 or more and can handle 100-mA ...

[Kevin Darrah] wanted to make a simple 3.3V regulator without using an integrated circuit. He wound up using two common NPN transistors and 4 1K resistors. The circuit isn’t going to beat out… ...

Buzzer Basics: Technologies, Drive Circuits, and Live Sound Demos The positive temperature-coefficient (PTC) thermistor in the pnp transistor’s current-control circuit prevents short-circuit damage.