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Topic: Need URGENT help with IC alternatives (Read 1 time) previous topic - next topic

AWOL

I've merged these to save anyone else wasting their time.

OP, DO NOT CROSS POST.
Is that clear enough?
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

twirap

okay guys. Thank you! I got home and ended up ordering that chip on ebay (Initially I didnt because I am short on time which is an issue when shipping is concerned) In the meantime I will build a voltage divider instead with the above recommended method

twirap


Let's start with the simple one.

For the LEDs you will need resistors - 120? to 150? should be fine (R=V/I = (5 - 2.8) / 0.02).

As for the chip, all that does is convert the 0-5V of the arduino to the 0-3.3V that the display needs.  You can achieve the same result in a large number of ways, not all requiring a chip.

For low-speed communications resistors arranged in "potential dividers" can be used.  For higher speed you can use diodes, transistors, any number of methods.


I ended up not needing any resistors because the digital i/o pins have very controlled current so the LED did not blow or even raise in temperature... I just connected led to GND and digital pin 13 and that worked just fine. The led is 2.8 v with 20ma current... The arduino has a 3 v power supply too so I would think that works well with this led as well.

twirap


You might find this video by Jeri Ellsworth helpful.

http://www.youtube.com/watch?v=XNIpvop0ruI&feature

Have you thought about using a voltage divider if you're going from 5v to 3v3 in one direction?



This is the first time I am even working with LCD displays. Buffers, level shifters is all new term to me :( I am not entirely sure of which way to go about it other than pay x5 more for that chip online since I did not find it at that store and making these voltage divider stuff is sooo complicated....

twirap

I am a little confused...

http://www.ladyada.net/products/nokia5110/#wiring

says you need a level shifter for a 5v microcontroller...Although arduino has a 5 V output pin there is also a 3V output pin...cant I just use that? I dont care about the backlight for now.

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