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Topic: 6 volts ok for this LCD? (Read 836 times) previous topic - next topic

Major25

I am going to be prototyping something on a breadboard with a HD44780 type LCD (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=310232911382&ssPageName=STRK:MEWNX:IT) and was wondering if a 6v source would be ok, or should I stick much closer to 5? My plan is to use 4 AA batteries (1.5v each, 6v total) to power the breadboard.

Also, as I bought the LCD on ebay and it didn't come with a data sheet or anything, does anyone know what the pin-out for those pins is likely to be?

Thank you

TchnclFl

Here's the pinout (it was on the auction listing):

http://www.sure-electronics.net/mcu,display/DE-LM005-4.jpg

I would try to stick closer to 5V.  Do you have some diodes?  Stick 1-2 in series between the batteries and the LCD.  Your normal 1n4001 diode has ~0.7V drop.

Major25

#2
Aug 23, 2010, 07:17 pm Last Edit: Aug 23, 2010, 07:17 pm by Major25 Reason: 1
Ok, I figured that was the case. Do you think using one diode (would you recommend an LED?) would suffice?

retrolefty

#3
Aug 23, 2010, 08:11 pm Last Edit: Aug 23, 2010, 08:14 pm by retrolefty Reason: 1
Quote
Ok, I figured that was the case. Do you think using one diode (would you recommend an LED?) would suffice?


Most LEDs drop 1.5 or more depending on their color type. A single silicon diode should be OK (say a 1N4001). From a HD44780 data sheet:

"The low power supply (2.7V to 5.5V) of the HD44780U is suitable for any portable battery-driven product
requiring low power dissipation."

http://pdf1.alldatasheet.com/datasheet-pdf/view/63673/HITACHI/HD44780.html

Lefty


Major25

Thank you so much for the information, it is perfect. I'll try ordering some of those diodes on ebay or something.

Major25

Do these look like they'd do the job? I just want to make sure before I purchase :]

http://cgi.ebay.com/12pcs-1N4004-rectifier-diodes-1amp-upgrade-1n4001-/330413495176?pt=LH_DefaultDomain_0

James C4S

Those are the exact diodes that were recommended.  You can also pick them up at RadioShack.
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TchnclFl

Yeah 1n4001 and 1n4004 are essentially the same (different reverse voltage tolerances I believe).  Both will work fine.  They're also very useful for other stuff such as motors and other coil-driven devices.

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