Post Reply 
Generic Calculator Shield for Arduino Photo-journal
03-12-2015, 08:05 PM
Post: #23
RE: Generic Calculator Shield for Arduino Photo-journal
(03-12-2015 07:23 AM)Marcus von Cube Wrote:  I'm not aware of any seven segment display device that is not multiplexed. The human eye is so slow that you will not notice a flicker unless you move the device in front of you. Multiplexing will reduce the power requirements to what a single digit or segment (depending how far you go with multiplexing) draws.

Yes... similar to PWM; only one digit is 'ON' at any one time... so, let's say we have 24 digits-- that means that at any moment in time 23 digits are technically 'OFF' but because of persistence of vision we still see them 'ON'... but, because they are off most of the time, it seems somewhat higher voltage would be required (or smaller current limiting resistors) so that the digits light just a little brighter for the 1/24 time that they are actually 'ON'?

I do actually see the flicker with my eye... and it drives me crazy (near sighted people are more sensitive to the condition for some reason). My display flickers a bit too because the 24 bits that fly by actually hit all LED bars before they come to rest. Since I have no latch enable line on my 273 devices I can actually see the flicker each time the display is written... but only because I'm sensitive to it, and partially because I'm looking for it.

Well, for a large display, multiplexing is required; a relatively mute point for me, since I probably won't be motivated to actually build my Wang 700c replica... but, I'm crazy, and you never know!


Kind regards,
Find all posts by this user
Quote this message in a reply
Post Reply 

Messages In This Thread
RE: Generic Calculator Shield for Arduino Photo-journal - MarkHaysHarris777 - 03-12-2015 08:05 PM

User(s) browsing this thread: 1 Guest(s)