Small LCD display help

Hey guys, I have a LCD display from my workspace, but I don't know how it works, I look at the pins but they were four pins and 2 connectors, 2 pins per connector. This was confusing, I look at the components but I don't know what they do, plus it's a MEC-301, please help.
This two pins of this display goes to the back light but there is two other pins that I don't know how it works, The segments just turns it on and stay on, sometimes it flashes too, if you don't know how to use this component then maybe it's old and unless.
I'm trying to program this display but I don't think it's PWM. It might be data send to it to make numbers and other characters.
IMG_20211102_081725

How did it work in your workspace? When you know that you may be able to use it with an Arduino.

Two requests:

  1. Are there any other Make or Model numbers on it? I searched and can't find any LCD/LED/TFT display related to the id "MEC-301".

  2. Please provide a better, more focused picture of both the front an the back sides of the board, and maybe a zoom of the connection points. The way connectors are labeled can provide a clue as to what kind of driver is required, e.g. serial, SPI or I2C.

I'm just curious, because it's a 7 segment lcd display, I want to see if it displays numbers also here's is the back of it.
MEC-301 back side

Well, if you're sure it is a 7-segment display, then you will need to find a multiplexer board to drive it. Otherwise the wiring and timing required is very intense. See here.

I think that will work, thank you, I'm going to get a multiplexer and try if it works.
Thank you haroldsutton.
:grinning_face_with_smiling_eyes:

1 Like

Nonsense. :grin:

The "multiplexer" - the driver electronics - is already in the COB chip on the board.

Given that there are only actually two 2-pin connections to the board, it clearly has a dedicated function - what is it actually? What does "from my workspace" mean?

No doubt one pair of connections is power, and the other is something to be measured - either a voltage or the resistance of a sensor. Plausibly, a thermometer module.

If you could supply useful focused pictures - at least 4 Megapixels - of front and back, we could likely identify something about the connections and how to safely power it up.

The chip in the top right corner is probably a regulator. Maybe something similar to the AMS1117.

This leaves 2 pins for the protocol. Could be anything. OneWire, i2c or just data+clock for a shift register.

Do you still the other board, where the LCD was connected to? Is it still working?
Also some better pictures would be nice.

Thank you all for my help, I like how you help me with a wiring, what is called and got my ideas. Thank you all :grin:

I think it will work, if it doesn't you can help me more.

Rintin I have struggles some how, it doesn't show temperature or humility. It shows segments lit then I adjust the resistance and it was flashing, I now know it's a thermometer, but It doesn't show numbers except flashing and segments lit.
I'm showing pictures of it.
Front of thermometer:

Here's the back of the themometer.

And this is the thermometer not show temperature but sold segments on.

Sorry for that, it's for everyone to help me.

Connect a thermocouple to the brown connector. If you don't have one, use a variable resistance to test instead.

Does the U2 part (smaller chip near white connector) heat up when you apply power? If it does, you may need to lower the voltage applied. Try to read its marking.

Thermistor.

We don't know for sure what was the original sensor...

It much of came from an ear temperature device.
ear_device

This type of LCD display is about the same size, and works very well with Arduino, using the standard LiquidCrystal library. Also available in 3.3V versions.

No, it's a LCD 7 segment display, with 7 segments on it.
Here's the picture.


The LCD display you're talking about is an LCD display that are 82 pixels and characters, this display has 7 segments on it and more segments like the battery icon and the E segments, also the dot segment and more segments, it's a thermometer not an LCD 82 characters.