Can't find current draw information for OLED modules

wapo54001

Senior Member
If the information exists, could someone point me to it? I think I've checked the various PDFs available and don't see any information on total current draw for the display board and driver Picaxe. hippy got my attention when he spoke of using TO-92s for most applications but a TO-220 for displays.
 

marks

Senior Member
Hi wapo54001,
it may depend which model you have some tests i did with the 20x4 @ 5v 55ma
i found you can safely drives these at 3v which will reduce current draw to 34ma with slight decrease in brightness.
recorded on drawing at #36 http://www.picaxeforum.co.uk/showthread.php?19474-Learning-to-Drive-an-LCD-DISPLAY/page4
so my prefference would be to drive these at 3.3v which seems to be common with new devices.
i havent tried the smaller version but have one ordered on the black special lol.
 

Goeytex

Senior Member
You can always measure the current to be sure, as it may vary significantly from model to model. Just put a 1 ohm resistor in series with the supply while filling the display with block characters. Then measure the voltage across the 1 ohm resistor. Each mv across the 1 ohm resistor will represent 1 ma of current. This will give you the max current. Then clear the display and measure again, this will give you the approx minimum current.
 

hippy

Technical Support
Staff member
My testing of a 16x2 OLED some time ago showed the 18M2 control board itself seems to draw about 5mA at 5V.

The OLED display seems to be less than 1mA when blank and about 34uA per pixel so that would suggest around 43mA if all pixels are on, 50mA for everything including control board as a ballpark to work to.
 

HertzHog

Member
=I think the approx. power consumption could usefully be added to the RevEd product data sheets..
I agree!

Quick question... I guess this answer is the same for LCD and OLED. My question is, after you have soldered up the board and connected + and - to the sub-board, but NO DATA pin yet, should you get something on the display e.g. a welcome message?

I have just soldered mine up, and I thought I had done a good job but while I can contact the 18M2+ via its serial lead, I can see nothing on the display. Is that no data so no display or it is not working? I don't think it is a contrast issue, 'cos I have tried changing that and I see nothing.
 

hippy

Technical Support
Staff member
My understanding is that the AXE133 18M2 is pre-programmed and will display a welcome message at turn on but do not have one to hand to test. The firmware can be re-loaded to ensure it does display a welcome message for testing by going to through the PE6 menu options of -

File -> Open Samples -> BASIC -> AXE133 - Serial OLED Display - > 18M2 -> AXE133 - Serial OLED.bas

Uncomment the appropriate line -

;#define use_OLED
;#define use_LCD

Comment out the following to not show the welcome message -

#define use_welcome
 
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