Retrieving LCD data to a PC

[jumpjack]

I have a power-consumption monitor which displays... power consumption on an LCD; I'd like to retrieve this data to my PC: can this be done? Could I use a PIC to "grab" signals from LCD pins and process them?

 

[seemanta]

detecting LCD data

Yes, it should be possible, although I never tried it personally.

Just connect the PIC in 'parallel' to the LCD.
You may then use the PIC to sense whenever the R/S,R/W and EN lines change state and then proceed to 'read' the data presented in the data lines of the LCD.

After reading, you can send this data via the parallel port to the PC where any program can be used to display it.

Hope this helps.

~seemanta

 

[jumpjack]

Re: detecting LCD data

Yes, it should be possible, although I never tried it personally.

Just connect the PIC in 'parallel' to the LCD.
You may then use the PIC to sense whenever the R/S,R/W and EN lines change state and then proceed to 'read' the data presented in the data lines of the LCD.

After reading, you can send this data via the parallel port to the PC where any program can be used to display it.

Hope this helps.

~seemanta

thanks, but I never played with LCD, don't know the jargon...
And, what voltage do they use? What should I look for? A digital output?

 

[seemanta]

detecting LCD data

Look up the data-sheet for the LCD. I presume you are using a Hitachi HD44780 compatible LCD. Most of the LCDs available are based on it, although they may not be directly manufactured by Hitachi. Also there are scores of material on the net for interfacing with LCDs.

R/S, R/W and EN are control lines in the LCD. It uses +5V for operation and yes, the output would be digital should you choose to 'snoop' on the LCD data as I mentioned in my previous post.

Good luck!
~Seemanta

 

[jumpjack]

Re: detecting LCD data

Look up the data-sheet for the LCD. I presume you are using a Hitachi HD44780 compatible LCD. Most of the LCDs available are based on it, although they may not be directly manufactured by Hitachi. Also there are scores of material on the net for interfacing with LCDs.

R/S, R/W and EN are control lines in the LCD. It uses +5V for operation and yes, the output would be digital should you choose to 'snoop' on the LCD data as I mentioned in my previous post.

Good luck!
~Seemanta

datasheet?!? How am I supposed to have the datasheet of an LCD of **broken link removed**?!? :?:

 

[seemanta]

detecting LCD data

Aaaah!! Now I get it. You have purchased it. I was thinking you made it yourself. In this case, it would amount to prying open your device and then 'hacking' it.

This my friend, would be difficult, if not impossible.
If you wanted to see the reading on a PC then you should not have purchased this.

~Seemanta

 

[jumpjack]

Re: detecting LCD data

Aaaah!! Now I get it. You have purchased it. I was thinking you made it yourself. In this case, it would amount to prying open your device and then 'hacking' it.

This my friend, would be difficult, if not impossible.
If you wanted to see the reading on a PC then you should not have purchased this.

~Seemanta

this is stuff for another thread: **broken link removed**
But I'm still interested on "hackin" mine...

 

[seemanta]

detecting LCD data

Then as I said, you would have to isolate the R/W, R/S, EN and yes, the data lines within your meter and then sense them.

Assuming of course, you have a HD44780 based LCD display.

 

[jumpjack]

detecting LCD data

Then as I said, you would have to isolate the R/W, R/S, EN and yes, the data lines within your meter and then sense them.

Assuming of course, you have a HD44780 based LCD display.

nope, it's not a dot matrix LCD, it's 7-segments based!

Added after 3 minutes:

To see if I can hack the LCD, I need some informations:
- are all 7-segments based LCDs working with same voltage/current?
- which voltage/current is needed to turn on one segment?

If I know which voltage to apply, I can just connect a voltage source to one pin, and move GND from a pin to the other till I see a segment turning on. But if I use imporper voltage, I'll burn all up!