# How to work out the interface of an LCD?

If I got an LCD, and I didn't know anything about it, and there were no markings on the pins, how would I go about interfacing with it? For example, I got this small (around 2.5") colour display out of an old printer, I tried everything I could, looking up a datasheet, asking on forums, but I was unable to get it to work. What is a general process I could use? Is there like, a few common interfaces I could use?

• First step: Count the number of pins. Second step: Observe the pins: Are they all the same size? Are they grouped in any way? Third step: Do the total number of pins or the number of pins in a group correspond with any protocols you can find? – Dampmaskin Jan 18 '18 at 9:20
• Okay, thanks for the advice, I don't have the LCD with me right now, but I will try it later. – skillz21 Jan 18 '18 at 9:21
• Very often these displays are custom designs so only the manufacturer of the display and company which made the printer know how to control this LCD. I expect that quite a lot of reverse engineering would need to go into this before you can use such a display in a meaningful way. If you really need a display for some project then it is often much less work to use a readily available display (from ebay for example) which also has software libraries (for Arduino or Rpi) to control it. – Bimpelrekkie Jan 18 '18 at 9:27
• Your best option is to buy a new one with all the data necessary to make it work - trying to reverse engineer it is probably a fruitless exercise... – Solar Mike Jan 18 '18 at 9:43

Another creative approach I can think of is to take a few pictures of your LCD and p̵o̵s̵t̵ ̵t̵h̵e̵m̵ ̵h̵e̵r̵e̵ use reverse image search. If your LCD is widely used, you will usually find out its model name. If not, I wouldn't even bother, since you can get a known LCD for as little as $2 from e-bay or similar. •$2??? Do you mean the 16x2 ones? I seriously doubt you could get a graphical LCD for that cheap. – skillz21 Jan 19 '18 at 3:46