Input Devices

Objective of this weeks Assignment

Input Devices

What are Input Devices?

A hardware which is used to provide control signals to microcontroller in order to perform a tasks. The data will be logged in system, using this data we can perform tasks which is linked to that data set.

The following components may be used as Input Devices:

• 1.) Switch
• 2.) Potentiometer
• 3.) Light Dependent Resistor (LDR)
• 4.) Photodiode
• 5.) Opto-isolator
• 6.) Proximity switch
• 7.) Thermistor
• 8.) key pad
• 9.) Hall Effect Sensor
• 10.) Phototransistor

I have used an ATmega328P with a sound sensor and a touch sensor connected on pin a2 and an led on pin a3, which will turn on the led.

To be familiar with ATmega 328P one must read the datasheet thoroughly. Since, there will be a lot of information in the data sheet, its better to refer to the pinout of the ATmega.

- I loaded the Arduino bootloader into into the Atmega328P.
- I used an Arduino Uno to load the Arduino ISP.
- Later, I configured the Arduino IDE to use the Arduino Uno as an ISP Programmer. (Click: Tools>Programmer>Arduino as ISP)
- Now it’s time to talk about our Atmega328P, I loaded the bootloader on it. (Click: Tools > Burn Bootloader)
- The ATmega will be ready to program.

Troubleshooting

- Make a backup copy of the file: avrdude.conf
- Open the file avrdude.conf in a text editor
- Search for: “0x1e 0x95 0x0F” (this is the ATmega328P signature)
- Replace it with: “0x1e 0x95 0x14” (this is the ATmega328 signature)
- Save the file
- Restart the Arduino IDE
- Continue with the rest of the steps as mentioned above, and once bootloading is complete restore the backup copy you made.

For this assignment I did the booting process on my previous board from assignment 10. I decided to use the same board, which I developed.

The board shown below will be used to achieve the goal.




I started milling the board and soldering all the components on my board.

Components needed for the board:

ATmega328P microcontroller	Capacitor C1,C2 22pF
C3 100uF	R1 10k ohm
C5 100nF	R2, R3 499ohm
LED 1	LED 2
1 USB connector	AVRISP SMD
1 Cystal 16MHz	1 Switch
Jumpers J1	Jumpers J2
Three 6 pin connectors	one ribbon cable
Two single header pins	SMD Jumper J3

Final Board designs:

Downloadable file: finalboard.brd

Downloadable file: finalboard.sch

Steps involved are :

Sensing : Adding a sensor to my microcontroller board.

Studying the datasheet of the sensor and understanding the sensor calibration curves, if any.

Workflows used in circuit board design. (using keil to add components and design my board)

Programming the board through Arduino IDE

- Touch Sensor

Grove - Touch Sensor enables you to replace press with touch. It can detect the change in capacitance when a finger is near by. That means no matter your finger directly touches the pad or just stays close to the pad, Grove - Touch Sensor would show a HIGH output.



Specifications:

Operating Voltage: 2.0 - 5.5V
Operating Current(Vcc=3V):1.5 - 3.0μA
Operating Current(VDD=3V):3.5 - 7.0μA
Output Response Time: 60 - 220mS
Used Chipset: TTP223-BA6

- Sound sensor

Grove - Sound Sensor can detect the sound strength of the environment. The main component of the module is a simple microphone, which is based on the LM358 amplifier and an electret microphone. This module's output is analog and can be easily sampled and tested by a Seeeduino



Specifications:

Operating voltage range: 4-12V
Operating current (Vcc=5V): 4-8mA
Voltage Gain (VS=6V, f=1 kHz): 26dB
Microphone sensitivity (1Khz): 52-48dB
Microphone Impedance: 2.2KΩ
Microphone Frequency: 16-20Khz
Microphone S/N ratio: 54dB


Touch ___________________________________________ Sound___________________________________________

Video for touch

Video for Sound

Downloadable files:

Downloadable file: touch.ino

Downloadable file: sound.ino