$4 LCD solution for BoeBot (or other Stamp apps), plus a bit of soldering...
Matt Nowinski
Posts: 5
Thought some of you might be interested to know that All Electronics Corp. sells a parallel LCD that works well with the code/pinout provided by Parallax for their parallel LCD. The All Electronics LCD is based on the same driver chip: HD44780 from Hitachi. It can be found here (for $4.00):
http://www.allelectronics.com/cgi-bin/category.cgi?category=365&item=LCD-107&type=store
Parallax's parallel LCD docs and code can be found here:
http://www.parallax.com/detail.asp?product_id=603-00006
For the Boe-Bot, I put together a quick, strip-board based interface circuit according to the Parallax docs referenced above. See the attached PDF. I designed the circuit to plug right into the header on the Boe-Bot board. Works great!
Drop me a not if you are interested and/or have any questions.
http://www.allelectronics.com/cgi-bin/category.cgi?category=365&item=LCD-107&type=store
Parallax's parallel LCD docs and code can be found here:
http://www.parallax.com/detail.asp?product_id=603-00006
For the Boe-Bot, I put together a quick, strip-board based interface circuit according to the Parallax docs referenced above. See the attached PDF. I designed the circuit to plug right into the header on the Boe-Bot board. Works great!
Drop me a not if you are interested and/or have any questions.
Comments
A $5 GRAPHIC LCD (plus s/h) with LED backlight then go here.
http://forums.parallax.com/showthread.php?p=556815
Just in an effort to provide complete and correct information for others, one ought to note the following about the All Electronics LCD (Cat. No. LCD-107) you mentioned in your earlier posting. This way, others can decide for themselves whether this LCD is suitable for their needs.
As advertised, this is a 2 line x 24 character back-lit LCD (some documentation included) which uses EL (electro luminecent) technology for the back lighting. However, the required EL inverter is neither offered with the LCD, nor is one presently available from the All Electronics web site, although they have offered them at prior times. Even when they were offered, they were not specifically indicated for use with this LCD.
Again, just as a matter of information, a suitable EL inverter for back lighting this LCD will have at least the following specifications:
Typical output voltage - 100 Vrms (200 Vrms maximum)
RMS (AC) voltage frequency - 400 Hz
Typical current characteristics - 6 mA
Regards,
Bruce Bates
A quick note for newbies, though. The design I presented does not use the backlightig capabilities of the All Electronics LCD - in fact, I simply desoldered the power wires corresponding to the backlight. They are not required. This is something I should have mentioned. Furthermore, the LCD sold by Parallax is not backlit; hence, no capability is lost by giving this alternative a try. Hope this helps someone out...
·· I think the reason Bruce brought up the backlight is that on some LCD Displays the backlight is required for a proper display.· There are different types of LCD Displays, Reflective, Transreflective (Transflective), Transmissive, etc.· I forget which is which (I went through this once) but a few are difficult or impossible to see without the backlight, if required.· It's hard for someone to know, sometimes, without actually trying.
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Chris Savage
Parallax Tech Support
csavage@parallax.com
That's a good heads-up!
Based on my experience, the All Electronics Corp. LCD model I cited works great without the backlight. So, cheapo tinkerers, enjoy!
And of course, many thanks to the guys at Parallax for the wiring docs and sample code. This surplus LCD would not have been much use without it...