LED triggered by LDR

The setting for the LDR exercise is the same as the button exercise except that the button is replaced by LDR(light dependent resistor) which leads to the environment light brightness as the factor controlling the LED's on/off. It is a simple interesting sensor-based electrical circuit.

The 2nd exercise is modified based on the previous one, but the output pin is shifted to the PWM which conveys not only the yes or no value but also how much the value is and what quality the value effects the environment condition.

button to control LED's ON/OFF & its brightness

After resting 4 2 weeks, i am back on my arduino journey. the new practice is about how to use button to control a LED's on/off and its brightness.

LED on/off is shown before, however, the interesting thing is setting the brightness by using the same button with PWM(pulse width modulation) concept. PWM is preset in arduino already. it is arrangement of the proportion of on and off to modulate the desired condition for brightness of LED or speed of motors etc.

it is a little exercise from chapter 5 in "getting started with arduino".