OLED burn-in

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bugs
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OLED burn-in

Post by bugs »

I use the small I2C OLED displays for a few projects and one of them has been powered on for probably a couple of years.
I noticed that some pixels were dimmer than others so I removed the OLED and connected it on the bench with a test program displaying ONLY a white rectangle.
The result shows the effect of long use.
The dark bars (and poor focus) are due to the camera.
image.png
I should have used a "press to display" pushbutton.

The SSD1306 has a register which allows a small amount of brightness control so I will add a few extra lines to the program to set the level to zero. This does not dim the screen very much. The attached program demonstrates the default level (&H7F) and the max and min (255 and 0).


CODE: xxxx.bas

--------------------------------------------------------------------------------

'Brightness variation demo for SSD1306 OLED display
'at I2C address $3C

'------------------------------------------------------
' this section could be in the setbright sub routine
Dim MyArray(2)
MyArray(0) = &h81 ' SSD1306 brightness register
MyArray(1) = &H7f 'default brightness
i2c_addr = &h3c : register = &h00: length = 2
'-----------------------------------------------------

OLED.INIT 0 ,1 ' init the OLED upside-down
OLED.CLS ' clear the screen
OLED.FONT 2
OLED.COLOR 1
OLED.PRINT 10,10, "HELLO WORLD"
pause 2000
do
demobright 255 'maximum level
demobright &H7f 'default level
demobright 0 'minimum level
loop
end

sub demobright(bright)
OLED.COLOR 1
setbright bright
oled.rect 0,0,127,63,1 'fill screen with white
OLED.COLOR 0
OLED.PRINT 10,10,str$(bright)
pause 2000
end sub

sub setbright(bright) 'this puts the specified byute into the correct SSD1306 register
MyArray(1) = bright
I2C.WriteRegArray i2c_addr , register, length , MyArray()
end sub
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Electroguard
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Re: OLED burn-in

Post by Electroguard »

Glad you've reminded me... I had intended adding a radar sensor to automatically brighten my tft touchscreen heating controller and have it dim out during inactivity, but forgot all about it.
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Re: OLED burn-in

Post by AndyGadget »

Do TFT displays burn-in?
I've just checked my earthquake display which has been running continuously at full brightness during the day and 1/4 brightness at night since August and I can see no sign of burn-in.
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Re: OLED burn-in

Post by Electroguard »

I used to think it was just CRT's which 'burned' by losing part of their phosphorous coating, but I have noticed that it also happens to flat-screen monitors and laptops.
So if it also happens to OLED's then it's likely to happen to anything which emits light, and there's no point me taking chances with a bright TFT.

Especially as it seems that chinese manufacturers don't tend to do re-runs after the initial huge production run of a new item, which is when prices are at their competitive cheapest.
So instead of selling off older clearance stock cheaply, the warehouse prices just keep on steadily rising with reducing availability... I couldn't get a replacement TFT now for anything like the original price I paid.
Same goes for Wemos D1 Mini 32's, Sonoff B1 lamps, and S20 relays, and all my original old workhorses.

I hesitated with the epaper32 for a couple of months and the price with touchscreen case almost doubled due to popularity reducing stocks, and I expect the manufacturers will only ever be doing newer products - so when you miss the bus you'll pay for a taxi.
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Re: OLED burn-in

Post by AndyGadget »

I hadn't thought about Chinese production that way, but I can see that you're right. LCD modules are stupid prices now.
I missed the boat on the e-paper modules too. I had a couple on order via AliExpress some time ago but the seller disappeared just after supposedly shipping them. I had to wait a long time but got my money back in the end.
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Re: OLED burn-in

Post by AndyGadget »

I just had a look at prices for Nextion displays - OUCH!
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Re: OLED burn-in

Post by Electroguard »

Yeah, that's the problem nowadays... settling on a cost-effective useful display which Annex supports, then buying enough extra to last for the foreseeable future.

Same applies to all the modules really... except that I think it may be possible to create replacements fairly easily using EasyEDA, cos the circuit design seems quick and easy, which is converted to pcb layout that can be sent for manufacture including supply and installation of all the SMD 'dust' which would otherwise be beyond me.

As a first project I'm working on a dual Wemos footprint board that will take either the original wemos D1 mini's, or the ESP32 successors such as TTGO, breaking out everything to headers, and using the common pins connecting to a couple of I2C headers (perhaps also TFT), plus providing plenty of headers for 5V as well as the usual 3.3v and Gnd. Is easy to add smd buttons and LEDS etc as well.
Some things I'll leave as optional through-hole components that I can solder in myself later if needed.

And when done, it should be simple to duplicate another above it with all support pins connected and TX and RX cross-linked, so it could either be used as 2 snap-off separate modules, or as a dual esp board.

And using the same dual-footprint allows for creating dual-footprint plugin expansion 'shields' that can be used with the original 16 bit wemos D1 mini's and the es32 successors, and the plugins might include I2C headers and radar sensor headers or anything.

Plugins could even cater to piggy-backing non-wemos footprint devices such as esp32 CAM, with all the wemos shields still available (underneath) and possibility for a dual esp to gain extra pins or processing power or whatever.

Nothing would ever become redundant, cos a new plugin adapter could cater for anything.

I need to design the circuit (almost done), layout the pcb, upload to jlpcb... then they send back the populated modules in about a week apparently.
And assuming the components remain available, more modules can be ordered if needed without having to pay silly money for missing the boat.

I think EasyEDA offers facility for sharing projects, so maybe I will try to create an EasyEDA shared access for anyone to be able to order their own pcb or ready-made items direct from jlpcb if they wish (I've only heard good things about them).

The same could apply to anyone else who uses the free EastEDA online circuit designer and PCB designer, they could share their pcb designs for other Annex users without needing to share any Annex scripts, so it might open up a lot of new doors for a lot of people.
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