system
August 23, 2010, 4:42pm
1
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
system
August 23, 2010, 4:55pm
2
Here's the pinout (it was on the auction listing):
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.
system
August 23, 2010, 5:17pm
3
Ok, I figured that was the case. Do you think using one diode (would you recommend an LED?) would suffice?
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."
HD44780 Datasheet, HD44780 datasheets, HD44780 pdf, HD44780 integrated circuits : HITACHI - Dot Matrix Liquid Crystal Display Controller/Driver ,alldatasheet, Datasheet, Datasheet search site for Electronic Components and Semiconductors, integrated...
Lefty
system
August 23, 2010, 6:15pm
5
Thank you so much for the information, it is perfect. I'll try ordering some of those diodes on ebay or something.
system
August 23, 2010, 6:23pm
6
cmiyc
August 24, 2010, 4:15pm
7
Those are the exact diodes that were recommended. You can also pick them up at RadioShack.
system
August 24, 2010, 4:26pm
8
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.