We got our hands on a few cheap 2×16 red/black LCDs of eBay for $5 a piece, these are the same LCDs from the unboxing video. In preparation to build the soldering iron driver, we tested them out with the Bus Pirate LCD adapter and the USB LCD Backpack. Initially we were worried that the red on black LCD would need a negative voltage supply, contrary to the advertisement, but it works great on a simple supply.
The USB LCD Backpack is available for $16.95 at Seeed Studio.
These looks great. They use some back light to light trough that red chars or ?!
btw, where did you get these lcd’s? how much were they?
It is red LED backlight through red chars. It was around 5 bucks from seller egochina, they have a bunch but it looks like most color combos (and this one) are sold out. Here is an example (I hate ebay links because they die eventually):
http://www.ebay.com/itm/Character-LCD-Module-Display-LCM-162-1602-HD44780-/190370286920?pt=LH_DefaultDomain_0&hash=item2c52f40d48
cool, thanks, very interesting.
My favorite way to generate a negative supply voltage is to steal the negative voltage off of a MAX233 or MAX232 chip. They can supply up to 10ma at -10v and up to 20ma. They are unregulated, so at higher current draws they put out a reduced voltage. This behavior is documented in the Maxim datasheet for the part.