So I got an obsession with this kind of machines which come in different shapes and designs. I initially planned to build a very simple analog circuit powered by a pair of AA rechargable batteries connected to SunMod solar strip, along with a resistor, an LDR, and an LP2950 voltage regulator. The idea was to change resistance with light, so when you stand infornt of the machine and block the light it starts to draw. Then Alex advised that I use Arduino for better resistance control, so I said OK 🙂 The idea is the same but the components are slightly different, so is the protocol. In this case, we will get the value from photoresistor using AnalogRead and feed this into the transistor’s base pin via PWM and thus change speed of motor with resistance. It is working now, however, the sensitivity of the LDR doesn’t seem to correspond nicely with the motor spin, I increased the base resistor, but still..so more tweaking is needed and vamos a ver ! 🙂 //more to follow