EEVblog #1045 - How To Drive an LCD

How to drive a static LCD display with digital logic and an Arduino / microcontroller.

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[Maltanx]

I really miss these educational video.
Please, bring back fundamentals Friday!

[PilotPlater]

Very cool. How LCDs were wired in products was always black magic to me and now it makes perfect sense.

[kktech]

These “Fundamental Fridays” were the highlight of the Eevblog. They were really good.

[aryesegal]

Thank you very much, Dave! Please keep these coming, driving LCDs was something I always wanted to learn how to do. As a beginning hobbyist, these kind of videos educate me a lot. I really appreciate all the time and effort you're taking to share with us! :)

[Darieee]

Would be interesting to see how dc-damage actually looks, and how long it takes to set in

[simplelyf]

Love the way you make hard things easier to understand!! Thank you Dave !

[glenslick]

Had to scroll back through the video a few times to catch the part number of that display. Looks like it is a Lumex LCD-S101D14TR. At Digi-Key it is part number 67-1506-ND. Currently listed at US $4.24 each for quantities under 10.

[MrMadDrago]

Nice!! You’ve answered a lot of questions Ive had Itching at the back of my head ... thanks Dave!

[brooknet]

You explain it so simply and clearly - thanks, Dave. I am proud to say that I sussed-out how to avoid the non-zero average voltage before you explained it fully, but I was completely ignorant of the 'stuck segment' issue until you mentioned it. From a long time ago, I recalled that LCDs are driven with a pulsed signal, but I didn't know why. Now, I do. Cheers.

[dentakuweb]

How can you NOT like a video with logic gates in it? :)
That's a very clever circuit.

[marcinborkowicz]

Dave, you should get Nobel Prize in education (and I'm sure the committee will create this new category especially for you)! Great video, man!

[reginaldmorton]

I needed this guy in engineering school 15 years ago__ much appreciated for the lessons.. NorCal

[bbreeuwer]

This is pretty much like a bridge (amplifier) circuit. They both have the same dc offset but relatively it's zero.
Very handy if you don't want a negative voltage.

[Lordniksidor]

Good on ya Dave, my LCD arrived from China yesterday now you make a video, I was looking for a modeling software, David did a video on that the next day... it's almost like our cycles have synchronized... cheers mate!

[daniszabo]

i really like this channel, i can't imagine what i would have done with electronics if he had been my teacher. he's awesome at explaining things.

[TomTRobot]

I think the simplest demo of how the LCD can see +/-5V across the segment while using logic that is only driven with 0V to 5V is by starting off using a battery-powered voltmeter. Call the negative probe on the DVM "LCD common" and show that if you hook common to 0V (logic ground) then when the driver is putting out +5V the meter reads +5V and when the driver is putting out 0V the meter reads 0V, but if you hook the the common to +5V (logic power) then when the driver is putting out +5V the meter reads 0V while when the driver is putting out 0V the meter reads minus 5V. Dynamically switching the LCD's common between 0V and 5V (relative to the driver) is analogous to dynamically moving where the negative lead is connected on a DVM. When common is hooked to 0V at the driver, the swing from the driver looks like 0V to 5V at the LCD segment, when hooked to 5V at the driver the reference is moved and the swing looks like 0V to minus 5V at the LCD segment.

[HsMalsn]

Love that episode!
The feel is just easy going Dave,
Thanks for the lesson : )

[MrJawol]

Top-notch quality educational material on Youtube

[telkentexas]

I love Dave Jones. He makes all others look like amateurs.

[upoupil]

make sense for beginner like me. thanks mr. dave.
your explaination answer many question of mine.