Display suggestion? - Page 1
Forum section: electronics / projects

author: reagle
author_rank: Unknown
timestamp: September 24, 2013, 02:58:44 am
content: Hello all,I am mulling over a project idea which would require a display with the following parameters:Functional directly from 2xAA batterieslow-ish power (a few mA or less)Sunlight readableNeeds to display at least 6 digitsSmall (sub 1/2" tall)Cheap $2-$3Easy to drive /low pin countSo far most of the usual suspects fell off due to low voltage or low power requirements or height limit (character displays, OLEDs, segmented LEDs etc). More exotic ones like E-ink and memory displays are too expensive.Still looking at segmented LCD ones, but it's tough to find low voltage one with convenient multiplexing to minimize pin count.I am trying to avoid voltage conversion, but wondering if that wouldn't be the easy way outSo, did I paint myself in a corner here?

author: mariush
author_rank: Super Contributor
timestamp: September 24, 2013, 03:14:46 am
content: I would look at something like this:http://uk.farnell.com/powertip/pc0802ars-awa-a-q/lcd-module-8x2-stn-reflect/dp/1671493(ignore picture on page, look at the picture in datasheet)+ Cheap+ says it can work with as low as 2.7v (but I have doubts about that)- would maybe have problems with visibility under sunlighthttp://uk.farnell.com/midas/mc20805a6w-gpr/lcd-2x8-grey-stn-reflective-5mm/dp/2063125+ Better under sunlightDatasheet says minimum 4.7v but considering it's supposed to use only a couple of mA, it may work with a simple voltage doubler.Can be driven with 4 data wires, enable , rs,rw (one of these 3 being optional), you have 16 characters ...

author: dannyf
author_rank: Super Contributor
timestamp: September 24, 2013, 04:12:00 am
content: Segment LCDs fit the bill.

author: mariush
author_rank: Super Contributor
timestamp: September 24, 2013, 04:23:33 am
content: He'll have a hard time finding a cheap ready made segment lcd with SIX digits or more, plus that means having a microcontroller with lcd driver or something like that (lots of i/o pins used)

author: dannyf
author_rank: Super Contributor
timestamp: September 24, 2013, 04:39:55 am
content: Well then, those HD44780 displays without backlight are very readable under the sun and consumes little current.

author: reagle
author_rank: Unknown
timestamp: September 25, 2013, 02:04:54 am
content: Looks like a small character display+ a voltage doubler or a boost is probably the best course to take.

author: EEVblog
author_rank: Unknown
timestamp: September 25, 2013, 02:22:21 am
content: Quote from: mariush on September 24, 2013, 04:23:33 amNo shortage:http://www.digikey.com/product-search/en?pv415=4&pv415=5&FV=fff40008%2Cfff80095%2C10c0007%2C10c0008%2C10c0018%2C10c001e%2C10c0026%2C10c0029%2C10c002b%2C10c002c%2C10c002d%2C10c002e%2C10c002f%2C10c0030%2C10c0031%2C10c0032%2C10c003c%2C10c003d%2C10c003f%2C10c0040&k=lcd&mnonly=0&newproducts=0&ColumnSort=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25

author: reagle
author_rank: Unknown
timestamp: September 25, 2013, 02:32:20 am
content: Correct, finding segmented display is not a problem. Driving it from a small micro gets painful, as I am trying to stick to all through-hole parts without resorting to DIP44+ packagesThis is for a kit, so being easy to build is an important quality. Does anybody make a segmented LCD with integrated driver and I2C or SPI interface by the way?

author: mariush
author_rank: Super Contributor
timestamp: September 25, 2013, 02:36:54 am
content: Quote from: EEVblog on September 25, 2013, 02:22:21 amQuoteI agree that they're cheap in quantity, but not so easy to drive as they don't have a controller.

author: reagle
author_rank: Unknown
timestamp: October 03, 2013, 06:18:37 pm
content: Thanks for the suggestions- I ended up finding a small character display. Easy to drive and fits the mechanicals