Fablabbombay | Sudarshan Kondgekar

Using ultrasonic module to check distance

In this week exercise I have decided to test working on ultrasonic module HC-SR04. This module has 2 ultrasonic sensors one of them sends a pulse and other one receives. This makes it possible to measure distance.

HC-SR04 Pins

Ultrasonic sendor module provided 4 nos of pins to interface it with other controller.

VCC : This pin is connect to 5 V power supply
Trg : To trigger measurement cycle. Make it ON for 10uS
Echo : This will become ON for travel time and give reading in uS

Designing of Ultrasonic board

I have decided to take a reference from Ultrasonic board available at Here
I have started designing it in Eagle

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Final Board Designed using Eagle

This board is an improved version of board. Which has eliminated all airwires.

Components soldered on Board

I had observed that initially there was a mistake in board

I had resolved it using a jumper wire connecting GND pin of HC-SR04. Later I had also modified board layout to correct this issue.

Programming of Board

Steps of programming

Program Board Using Arduino or FabISP Use prgram
- hello.HC-SR04.c : This is a program to be burned on board
- hello.HC-SR04.make : Make file to burn program
- hello.HC-SR04_SYK.py : Pyton program which creates UI to show readings on screen.
You need to install TKinter python library to create UI using python. Without which you will encounter with following error.
```
Traceback (most recent call last):
  File "hello.HC-SR04_SYK.py", line 17, in 
    from Tkinter import *
  File "/usr/lib/python2.7/lib-tk/Tkinter.py", line 42, in 
    raise ImportError, str(msg) + ', please install the python-tk package'
ImportError: No module named _tkinter, please install the python-tk package
```
Instructions to install Tkinter can be found here -> http://www.greenteapress.com/thinkpython/swampy/install.html
On Linux you can use following command to install Tkinter
sudo apt-get install python python-tk
Additionally you may encounter with error like
```
Traceback (most recent call last):
  File "hello.HC-SR04_SYK.py", line 18, in 
    import serial
ImportError: No module named serial
```
Resolve this by installing serial.
sudo apt install python-pip //First install pip
pip install pyserial
This will install required pyserial package
Connect board to PC using FTDI USB cable
Run hello.HC-SR04_SYK.py python ptogram to start UI
python hello.HC-SR04_SYK.py

Video of Ultranosic sensor working

Files for download

This board is an improved board which has eliminated all airwires

InputBoard.brd InputBoard.sch hello.HC-SR04.c hello.HC-SR04.make hello.HC-SR04_SYK.py