How to send LCD output to Arduino?

[aatefi]

Hi All,

I have a RPM speed meter (https://www.amazon.com/gp/product/B00VKAT8A2/ref=ppx_yo_dt_b_asin_title_o05_s00?ie=UTF8&psc=1) and the output of the senor is shown on a LCD. I can see four pins (+5V, GND, Rx, Tx) on the LCD (red box in image below). I am wondering how can I send the LCD output to Arduino (for example print the data on Arduino serial monitor)?

Thank you for your help in advance.

Abbas

[Railroader]

Usually sending data from an LCD is not supported. However those two pins, Rx and Tx, are interesting.
Do You have access to an oscilloscope so You can have a look at the Tx?
Try to get hold of technical documentation for the unit....

[jremington]

Why do you think these are "outputs"? RX is usually an input.

[anon57585045]

Why not just sample the tachometer signal from the fan directly, using an Arduino input? It's been done successfully by hundreds or thousands of people.

[aatefi]

Hi Railroader,

Thank you for your reply. It seems reading data from LCD it is not possible or complicated, so I am going to read the signal from the sensor.

[Railroader]

I thought so too but didn't want to show off.....

[aatefi]

Hi jremington,

Thank you for your reply. I thought since the LCD had RX and TX, these are pins to receive and transmit data.

[aatefi]

Hi aarg,

Thank you for your reply. Since the LCD directly shows RPM, I was wondering I can directly read the data from LCD.

I found the code from the link below to read rpm from a hall effect sensor (similar as mine), do you think will it be useful for my application?

Arduino tachometer without lcd screen

Hi everyone. I was trying to make my own tachometer without lcd screen so i can use my serial monitor to read RPM (rounds per minute). All of the tutorials (i found a lot) were using lcd screen. So i managed to find someones code with the use of serial monitor only and i tried it out. I found that he was wrong in the conversion of RP(ms) to RPM so i made a correction and want to share it with you. in my case worked just fine with a hall sensor. The infrared sensor was not that accurate. Before …

[jremington]

@aatefi

these are pins to receive and transmit data.

Sure, but what data?

The sensor you linked does not have an LCD. It has a seven segment LED display.

[aatefi]

jremington,

Oh, I am sorry. You are right, it is a LED.
I mean the data shown on LED which is rotational speed in rpm.

[jremington]

Ask the seller about the purpose of those connections.

An oscilloscope or logic analyzer might reveal something interesting on TX.