Here is the circuit of an Arduino-based Panic Alarm ... and the Push-ON (push ‘n’ hold) switch (S1) to activate the alarm function. An additional Electro-Magnetic Relay (EMR) is also attached to the ...

Thereafter, you should push the reset switch once to make the system fully functional ... That’s all! /* * SIM800L SMS RELAY v1.0 * Arduino Hardware (Author): Nano V3 (ATmega328) * Arduino IDE (Author ...

Push-wheel switches are somewhat older technology, but [John Boxall] from the Little Bird Electronics blog shows us that they are still quite useful today. In a quick but thorough demonstration ...

[Ed] was tasked with adding push-button degaussing ... to use an SSR to switch the coil, and after making lots of transistor-based designs on paper, grabbed a nearby Arduino.