Almost finished now, so I thought I'd post some pics (sorry about the flickr hosting! now on Imageshack): Outside: (I still need to file those buttons down, and increase the backlight strength) And nightshot: On the inside: An FT232BM board (USB->serial) on the right, and a board with an AT90S8515 AVR that spreads all the way across behind it. You can just see the top edge of the LCD (at the top, duh) And an exciting photo of it months ago, before I'd even made the usb converter! I'm gonna write a how-to guide for the electronics later this year (after GCSEs I guess), using a USB PIC (18f2550), rather than the nasty surface mount FT232BM I used, assuming the demand is there, so say if you want one! ch424
That's pretty cool. I know plenty of people will like a USB or even serial way of cooking up an LCD. I used the parallel port myself, but for those of you with a printer this is pretty cool
OK, 14 votes out of 271 views is 5% -- looks like a yes then! Thanks for the comments beast and smoguzbenjamin. ch424
If this could be done with a (relatively) cheap PIC and a 4x20char LCD i'll be interested.. (finally a use for my PIC programmer! )
I've got a PIC18f2550 coming in the post from Thailand (WTF?), which cost £4.39, or $8.25US (If I were american EDIT: or Norwegian ). You might need to do a software update on your pic programmer though. Yes, it will work with a 20x4, as long as its an HD44780 LCD. In terms of features, I aim to have: software backlight control (on/off, and maybe pwm brightness), hardware contrast, matrixorbital style buttons (up to 25), and matrix-orbital style GPO controls, as well as all the regular display controls (like go to top-left, clear screen etc.) If people can think of other features that I've missed, please could they post them? Thanks, ch424
just wondering: What's so special about the 18f2550? Oh! And how about software support... Will i be able to use programs such as jaLCD?
the 18f2550 has built in usb support, allowing for less parts. I'd love to see a kit for the 18f2550 or 4550 since I've got programmers and a couple PICs on the way to me. does the 18f2550 have enough I/Os to support what you want to do?
It has built in USB! And 256 bytes of EEPROM to save the LCD settings in! w00t! It should support any software that supports serial LCDs. Yes: 8 pins for lcd data, 4 for lcd control (E, RS, RW, BL), 2 for USB, 10 for buttons = 24 and there are 25 I/O pins, leaving one for GPO. If I only used a 4-bit wide data bus, there could be 5 GPOs. ch424
ah! ofcourse! This might turn up to be good... I don't know about upgradiong the programmer.. i guess the only thing needed will be an adapter if the programming pins is in different locations. It might need an upgrade on the software side...
If you use one of the microchip IO expanders that use I2C, you could have tons of buttons and/or GPOs
Thanks for the suggestion, I'll have a look! But you realize that 10 pins for buttons = 5+5 Therefore with multiplexing 5x5=25 buttons. And 5 gpos is quite a few, right? Well, if you read the first line of my sig... Thanks for the other comments ppl! ch424
Looking pretty good, I like it. The lines could have been neater where you have cut out for the lcd itself.
Looks nice I look forward to a guide, so I can build one =) I like the "above the monitor" idea. Or maybe a long-cabled one that I can stick outside my [bedroom] door, and broadcast messages on (I am [not quite] 15, hence living with my parents, so it'd be pretty cool =))
looking good! one of those projects i wish i had the electronic know-how to pull off without a guide you mean like "hey i got ladies in here, stay the f*** out!"
Cool idea, but if someone presses two at once, it would give a different button altogether (eg button 9 and button 18 together would produce 27) and you'd be like wtf? Also, 25 is the max supported by most computer-side software. You're right there I've tidyed them a little bit since the photo was taken, but ther'e still messy Cheers for the other comments ppl ch424
But you'd get that with Multiplexed buttons too (Press 1 and 17 and you'd get "Phantom" signals for 2 and 16) Now that I didn't know, though I've not seen that "Limit" mentioned anywhere...
