Hello, at first I want to apology if I posted not to right place(I am new user).
My goal is to listen lcd backlight screen and get this data to PC. Imagine ordinary device with such screen, for example calculator. When I click on ‘5’ button i want to synchronously send this data on PC, and then make additional calculation. If it is possible, please reply.
It’s possible… Since you posted in an Arduino forum, you can send a character to an LCD screen then simultaneously (well almost) to the PC through Serial.
Can you give me more information? What to learn, how to to achieve this?
You can use Google. “arduino lcd” “arduino serial” etc…
We are not here to do the work for you. Once you get started, if you have a specific issue you can’t solve, that is where we come in. But, to type all of the instructions to do this project, no, sorry. There are tons of tutorials for the Arduino that is already typed and most with pictures even.
Actually you need to give us more information. While possible to do, how it's to be done hugely dependent on the display and what access you have to it. Do you have some specific device in mind ? Do you have access to the pins connecting the display to whatever is sending the info to the display ?tungula:
Can you give me more information? What to learn, how to to achieve this?
OK, my device is “CP-3007 is a ultrasonic distance measurer”, here are pictures [
At first I am interesting which additionally device should I have to achieve my goal.](http://postimg.org/image/6ciltcrpb/)](http://postimg.org/image/degjfjvb3/)](http://postimg.org/image/ocrsxqjwf/)
It’s going to take some “simple” hacking but if you’ve not done this type of work before, then perhaps not so simple …
Your last pic shows the LCD w/20 pins to the PCB. It’s likely that 16 of those are the following functions (though the actual pin numbers may be different).
Your job is to ID the 8 data lines and 3 control lines (RS, E, R/w). Of the latter 3, one (R/w) is generally not used and left in the write state. It’ll take a bit of informed guesswork and testing to arrive at the 10 used.
You could use an Arduino Uno (you’ll need to find or write some code) as a low-cost, low-speed logic analyzer or use a Bus Pirate.
https://www.sparkfun.com/products/11021
https://www.sparkfun.com/products/12757
https://www.sparkfun.com/products/9544
Your choice. In the end either way should allow you to collect the data needed to recreate what’s on the LCD.
As I see no my scheme only first 7 pins are connected
If true that means they used the also common 7 pin data scheme. The upper 4 data bits are not used and instead the lower 4 bits are used to clock in 2 nibbles, one after another. Read about that here ...tungula:
As I see no my scheme only first 7 pins are connected
http://arduino.cc/en/Tutorial/LiquidCrystal
Now I am surprised that there’s not a power pin and a backlight pin(s). Perhaps they’re on middle layers you can’t see ?
Or it could be some serial interface for the data. As I said, it’s going to take some “simple” hacking.
Are there traces going under the LCD to the other pins? Total traces on both sides are more than 20, so Mee_n_mac might be right after all. Those on the right in the 2nd and 3rd image must be going somewhere, and I see nothing else connected on the board there. Could they not also be going directly to the number and symbol segments?
Tungula, can you make a picture with working display, showing numbers and additional symbols? So we can figure out how many segments are on the display.
This Atmel document may help with getting a better understanding of directly driving LCDs with an AVR chip (which most Arduinos are) , that do not have driver circuitry onboard (dumb glass). Or to just understand how the distance meter might do it. To make the segments go black they need AC signals. Static DC signals damage it. So it might be useful if you can also get some kind of oscilloscope to measure the signals on the pin. The frequency is not so high, so even a poor-man’s oscilloscope (Arduino or soundcard based) would do.
It can probably show more segments than that.
Just to illustrate the above. On one face of the PCB (shown below) you can see 4 traces going to pins on that side (outlined in red). Then there are 1+4+9 traces that are going out and under the LCD (outlined in blue) to ... somewhere ? On the backside of the PCB I don't see any vias or other indications of some connections. I doubt they are being routed to where they go if they're to go to someplace other than the LCD.Valen:
Those on the right in the 2nd and 3rd image must be going somewhere, and I see nothing else connected on the board there.
AFAIC there are 18 connections to the LCD and an O-scope or logic analyzer would quickly determine which pins do what.
Thanks guys for such support, but at first I want to simplify my work as controlling monitor is quite difficult task for me. Let’s first control just keyboard.
I find that connect two pins simulates click event on device, how to simulate this with event from PC with USB connection? (As I have already googled some pages find that I should use transistor)
This link describes how most keyboard switches are arranged in general.
http://blog.komar.be/how-to-make-a-keyboard-the-matrix/
There is a 8 trace- ribbon cable connector on the side of your main pcb that likely goes to a smaller pcb with the front push buttons. But that is not shown on your photo’s. The switches are likely using carbon pads to connect traces on the keyboard pcb when you push it. You’ll have to follow these traces to find out which button makes which pins connect to each other. Also be aware that some buttons might share traces, as the link above should explain. You have 10 buttons or so on the front, but only 8 pins, so something must be shared. There could be diodes parallel to the switch of a button. This is important for it’s function so make sure you include this in your investigation.
Only after you figure out which buttons make which connections on the connector should you worry about how to get this connected to the PC/USB/Arduino/whatever.
Actually I have already investigated. Now, I worry about second part, “PC/USB/Arduino/whatever”.
That is great news. If you want suggestions then you should share those results. We don’t know how your specific range meter is working.
Voltages
Current (directions)
Resistances
Were there any diodes?
Which/how many pins do what with a certain button.
etc.