LCD or LED display via RS-232?

Hi OptoPals,
Any suggestions for a small (cheap!) little display, perhaps RS-232, for someone who wants to display just a line or two of info from a SNAP-PAC-R? (We’ve used various LED or LCD displays around here, with varying levels of reverse-engineering needed depending on the quality of the manuals…)

i use these displays and rip out the picaxe and put a custom programmed PIC 16f628A micro in that takes serial data and displays it (why? well because i couldn’t get the baud rates working between 2 micros on a project so when i replaced the picaxe with a 628A it just worked. No reason why it won’t work with a pac and the picaxe). the oled displays are damn sexy i think and if you put a max232 daughterboard on there somewhere you can interface with rs232 (its only TTL on the board).

i just did this exact thing only last week for a job where i used one of those oled displays, made a 232 daughterboard, used the 3 header pins on the cct board for power and serial data and bam!! away we went displaying data from a pac-s2. in the end i think the display was AU$30, pic free from microchip, max232 chip and parts ~AU$6. so pretty cheap display. only gotcha is that is a software uart not a hardware uart so i had to delay 5msec between sending characters.

You might take a look at using an Arduino Uno with LCD shield. If you shop around you can find the total solution for under $30 ( and much of the Arduino code already exists as open source libraries from the community. It would be left to you to write the Adruino code to receive the data and send it to the LCD.

I am using this 4x20 character backlit screen ($25) available from Digikey (p/n NHD-0420D3Z-FL-GBW-V3) or Jameco.
The Opto22 serial adapter is plugged into a RS-232 to TTL converter, Jameco p/n 2157845 ($10). There are other converters available from Digikey that are more expensive but might be more reliable.

The operation is easy, just send a few characters to set the cursor position, then send the characters to display. There are commands to clear screen, set backlit level, and create custom fonts.

Corey Hughes

There are several types out there that are simple to use, one being from parallax which is a simple 5V power with serial interface. I used them with IO Control years ago. Another is from Nematron with the optimate series if you want a nice panel mount but with those if you don’t communicate with it within 2 seconds it can start flashing. They’ve been bought out a few times so I’m not sure if they are still available.


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I found the programs for the LCD displays and attached them. I remember now that I used the blue lcd from Netmedia ( which has a serial interface built in.


GarySRV Control (57.4 KB)

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Wow! Thank you for sharing!