The project of A sensor-driven mood lamp in week three Meeting

In week three meeting, students researched the circuit diagram of the operational amplifier.

The main function of an operational amplifier is to amplify the input signal, and the function is better with the more open loop gain (Avo). Open-loop gain of which values range from 20,000 to 200,000 is the gain of the op-amp without positive or negative feedback. Input impedance (Zin) is the ratio of input voltage to input current, and is assumed to be infinite to prevent any current flowing from the source supply into the amplifiers input circuitry. The output impedance (Zout) of the ideal operational amplifier is assumed to be zero acting as a perfect internal voltage source with no internal resistance so that it can supply as much current as necessary to the load. The Voltage Gain (Av) of the operational amplifier can be found utilizing the following formula: 

Voltage Gain, (A)=Vout/Vin 

and in Decibels or (dB) is given as:

20log(A) or 20logVout/Vin in dB 

After that, we understood the main function of this operational amplifier. Then, we tried to wire the circuit diagram of LED and took a video of that in the follow:

It could be seen that when the student's hand was closer to the receiver, the LED light was brighter. That phenomenon was conform to the situation for the distance sensor. 

And in the next week, students will connect all the elements in this design in one circuit and test it to acquire the result. 

Figure 1 shows the code of the ordinary situation we choose when starting the board.

Figure 1: demo code

After that, we started to test one group of RGB LEDs. LEDs were divided into two groups, one group were connected in series and two groups were connected in parallel.

The video shows one group of RGB LEDs shining after downloading the code.