Sunday, April 3, 2011

Project 23 - Basic LCD Control - Error in Book - Fixed

After some frustrating time spent looking over this circuit, I finally figured out the problem. Figure 8-1 does NOT show pin5 on the LCD being connected to GND. I'll take partial blame for this, however, because on page 172 Table 8-1 clearly shows to connect pin5 (R/W) to GND. I had to consult the data sheet to confirm that pin5 was R/W, but after doing that it was a simple matter of using a jumper wire to get it connected to GND.

Video is below - as you can see, I got the contrast to work by adding in the recommended potentiometer. That's a 5k, btw, not a 10k. Also the resistor for pin16 on the LCD is brown-black-black - a 10 ohm resistor. I got this 16x2 from Sparkfun, part # LCD 09054

So... Project 23 works... which gives me hope for Project 24 since it simply builds on this circuit a bit.


  1. That's great! By the way, to make your wiring look a bit neater, the wires for the power and ground rails (the white wire on the right looks like one) should be at the end of the solderless board and left there permanently because you'll rarely need to disconnect them and could use the room in the middle for everchanging projects.

  2. Great Job... Can you please tell me/us what is the name of the book that you use in the video ?

    Again congratulation for all the great tutorials ;)

  3. I'm reposting this since you mentioned comments may have been disabled temporarily. The picture here shows what appears to be a white jumper wire on the right connecting the power or ground rails. I suggest you keep it at the end of the breadboard so there's less clutter in the middle and you less likely would have to move it. I have power and ground wires that rarely are every moved.

  4. E.[Y]², are you asking about the book this blog is based on? That's "Beginning Arduino" by Michael McRoberts... there's a link to the book on the blog's main page near the top right corner.