Turn off and turn on a LCD IIC/I2C/TWI Serial 2004 20x4? How to do it?

Projects General Guidance
1

Good evening dear gentlemen from the arduino forum,

I have a question that I hope you can help me.

I have a LCD SainSmart&reg IIC/I2C/TWI Serial 2004 20x4 which you can find in the following link

In the project that I am currently doing I need to take care of the battery consuption and it is required that in certain periods of time I turn off the LCD. I already tried using a switch buttom which is connected to the 5V pin of the LCD (this LCD only has 4 pins SDA SCL VCC GND) and of course it works to turn the LCD off but at the moment that I trun it off everything that was in the display and that should be there disappears, and some strange characters appear, therefore, I believe this is not the solution that I need. I was reading something about turning the back light off, but is that what I really need? Is there a code like for example:

lcd.turnoffwithoutmessingupthescreen(); or something like that? Could you please help me?

Best regards,

Sebastian

2

Once you turn off the LCD it has to be reinitialized before it will begin to work properly. As to what it was displaying prior to turning it off will have to be restored by your software. You can read the contents of the DDRAM and store in an array before turning the display off. When the LCD is turned on and initialized return those bytes to the DDRAM.
By far the backlight is the major consumer of power and is easily turned off by setting the bit that controls the backlight to '0' (usually). You will need to look at your datasheet for the display to determine which bit of the PCF8574 has to be cleared.
Another option would be that most of these I2C interfaces include a jumper for enabling and disabling the backlight. You could replace the jumper with a switch or transistor. I use a 20x4 I2C LCD and the backlight draws about 20 mA.

3

Thank you so much for your response, any other ideas please?