lcd wrong characters

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#1
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I still busy with my line following robot, after an interrupt of a few weeks(read a month), I have the following problem:

When I power-up my robot, the sensors are 'seeing' white, so the motors are off the lcd is working OK. When I let the sensors seeing 'black' the motors turn on and the lcd isn't working OK anymore. See http://lcdprob.naffets.nl for some pictures/movies of what I'm see. What you see, when the motors are of are the ADC values off the sensors.

Last Edited: Mon. Mar 5, 2007 - 03:24 PM
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Do you ever get the proper characters on the display?

WHenever I get the "extended" characters, I have a problem with the communication speed.

Are you using a parallel or serial interface? If serial, it could be a baud rate problem.

If parallel, then it could be a timing problem, or a signal line (4 or 8 bit modes) could be stuck high.

-Tony

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Yes, I'm able to send and show the right characters on the lcd. When I turn on the motors, I get the wrong characters.

The motors have an external power supply. The ground is only wired together.
BTW it is a parallel interface

Last Edited: Mon. Mar 5, 2007 - 03:37 PM
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EMI interference maybe?

- Jani

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And what I do about it? I've some 4007 diodes between the to motors.

Sorry, I cannot find the schematic :S

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You need a BFC on the 5V line.

Imagecraft compiler user

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Thanks, but what is a BFC? Or are you joking?

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You get an interesting result if you look up BFC on WikiPedia. I have a sneaking suspicion the answer you are looking for is there ;)

Cliff

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I've got one on the bench here... its blue, about 2" diam, 3" high, has #6 screw terminals on top, couple 1000 uf at 35V.... by golly the VCC is rock solid with that bad boy on it.

Imagecraft compiler user

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Thanks for the tip.... will try it!

@Bobgardner You are the funniest at home? :mrgreen: