Week 4

This is the fourth lab week for Y2 project. With the first four weeks work, our group project have already achieved the prototype of the conveyor belt sensor by using two Arduino Uno chips. Below is the pictures of our first  temperature-temperature and temperature-speed circuit respectively.

Figure 1: prototype of the temperature-temperature circuit

Figure 2: prototype of the temperature-speed circuit

Below is the proposals of this week;

1. Test the output Pin 9 of the Arduino UNO chip utilised in temperature-speed circuit;
2. Draw the Arduino layout circuit by using software Fritzing;
3. Start soldering the circuit according to the Arduino layout schematic;
4. Test the electric fan working on the temperature-temperature circuit and try to combine these two functional circuit.

The output of Pin 9 from Arduino board in temperature-speed circuit is shown in figure 3(a) and (b):

Figure 3(a): Pin 9 output when the temperature is 42C

Figure 3(b): Pin 9 output when the temperature is 51C

It can be shown that in figure 3(a), the average output voltage is around 276mV and in 3(b) is 498mV. The comparison between different temperature conditions indicate that, for higher temperature, the duty time in PWM voltage output will also increase to drive the motor in a higher speed.
The layouts of the temperature-speed circuit and temperature-temperature circuit are shown in figure 4(a) and (b) respectively:

Figure 4(a): Arduino schematic for temperature-speed control circuit

Figure 4(b): Arduino schematic for temperature-temperature control circuit

Here in figure 4(b), an PMDC motor is replaced for the electric fan.
The rated voltage of the electric fan is approximately 5V. After adjusting and testing, a 6V battery is connected to the collector of the transistor and a $1000\Omega$
The last part of this post, I will show you a draft interpretation of our temperature-speed circuit roughly: