In this post we are going to construct an electronic notice board which can display short announcements sent from your cell phone.
We will see:
How to operate this project
Are you a teacher or principal or someone in an office who makes frequent announcements or passes important announcement to your colleagues? Then this project can make your life easier. You can pass or make a short announcement to your colleagues from anywhere in the world by a push of a button.
This electronic notice board may be placed at corridor which is the sweet spot for making announcements and only place where students/employees/colleagues gather and talk, making announcement on a notice board placed at these spot will make the announcement to go viral with your colleagues.
The proposed electronic notice board may be place beside an ordinary notice board. This electronics notice board makes pleasant music whenever new message/announcement is received; it also shows the time when the announcement/message was received.
Working of Electronics Notice Board:
The proposed electronic notice board utilizes the existing cellular infrastructure; that is, the existing wireless telecommunication system. We will be accessing the GSM / 2G network on 900 MHz or 1800 MHz band.
To access the GSM network we need hardware and appropriate firmware, fortunately we have ready-made development kit and this hardware is commonly known as “GSM Module” we can use SIM 800 or SIM 900 model for this project, you can also try any other GSM module.
Illustration of GSM Module:
The module is as small as Arduino UNO R3 and has 4 pins Vcc, GND, Tx and Rx. You should always power the GSM module with wall adapter.
There are 2 push buttons, power and reset; 3 LEDs one for power and one for status and one for network; we will not be using the RS232 port.
This is the flipside of the GSM module which reveals full size SIM card slot, where you need to insert your valid SIM with working SMS facility.
The GSM module is connected with Arduino via software serial which provides bidirectional communication between the two boards. The Arduino is the brain of the project and GSM module is that heart of the project.
The Arduino is the decision making device which controls the LCD display and decides whether to display the incoming SMS or to reject. The GSM module connects the Arduino to cellular network.
To display an announcement on LCD, you should start you SMS with @ and your message/announcement and end with *, only then the Arduino accepts the SMS and display on LCD. You will learn how to operate this circuit at the end of this post.
The displayed message will be scrolling left like flash news with the time it received.
Real-Time Clock Module:
To keep track of received message’s time, we are utilizing an RTC module.
The RTC module consists of 3V lithium battery, IC DS1307 and couple of pull-up resistors and a bypass capacitor.
The battery can provide backup for at-least couple of years without being powered by an external supply.
There are 4 pins Vcc, GND, SDA and SCL; it communicates to Arduino with I2C protocol.
Now let’s explore about LCD display.
I2C LCD adapter Module:
We are using ordinary 16 x 2 LCD display with I2C adapter module. The LCD’s I2C adapter module just utilizes SDA and SCL pins for communication just like the RTC module.
This module reduces the number of wires connected to Arduino from LCD display.
As you can see only four wires are connected to the LCD module.
This LCD adapter module can be soldered directly on the back of LCD display or can be plugged on bread board like illustrated above.
There is a pre-set resistor which can be adjusted with a small screw driver which controls the contrast of the display.
A jumper on the right side controls the backlighting of the LCD, removing will disable the backlight. We can also control the backlight in the code.
We will be constructing this project one with LCD adapter module and one without the LCD display.
Now let’s dive into the circuit diagram:
Circuit Diagram for GSM Electronic Notice Board:
The circuit is powered from 9V wall adapter with 1A current; the circuit is self-explanatory and connect the wires as shown in the diagram, the above circuit is with I2C LCD adapter module.
You can download the I2C LCD library from here and add to Arduino IDE:
With completed hardware setup turn on the circuit from 9V wall adapter with at-least 1A rated.
Send a message which is not greater than 39 character including spaces. Above 39 characters, your message will be truncated and the information you’re trying to communicate will be unclear.
You should start you message with “@” and end you message with “*”. Example: @2mro school is holiday due to rain*. Message without the start “@” and end “*” characters, your message will be rejected and will not be displayed.
You should send the message to the SIM card number which you installed on the GSM module.
Once your message is received, a pleasant music will be played to notify that a new message is arrived. Your message along with time will be scrolling to left like flash news.
If you have any questions regarding this project, feel free to comment below, you can anticipate a guaranteed reply from us.