Have a question on Arduino? Ask our expert Simon Monk

Hi Shelton,

Yes, it should be possible to build your own.

This blog shows details on what they did to make a line following robot, and includes a diagram of how the sensor works, with a circuit diagram.

http://www.ermicro.com/blog/?p=1097

Hope that helps

Cheers,

-Nico

thanks a lot !!

i also have an arduino, can it be used to make a line followin robot??

an arduino uno

I need to drive an I2C liquid crystal display (FEC: 206-3203) using an Arduino mini-pro, as part of the control system of an item of equipment to be manufactured in small quantities. I had hoped that using ready made libraries would speed the development, but it seems maybe not as much as I had hoped.

It seems that the LiquidCrystal_I2C library I downloaded is not suitable to drive this display - does anyone know of one that is suitable?

Failing that I need to choose the best way forwards. One approach would be to wire in an ISP connector and program it all in C. (I am not yet a very experienced C programmer but have coded several embedded projects including one using I2C. My core skills are power electronics and analogue.) Another approach would be to stay with Arduino code and use the I2C library to write display drivers using Sketch. This might be quicker if it works, but is it likely to hit a roadblock somewhere forcing me to start again and use C?

In either case there will have to be some trial and error because the data sheet for the display is only almost clear on how to use it.

Can you suggest another and better approach to try?

Have you tried the I2C LCD library that comes with the Deuligne LCD deisplay?

http://shop.snootlab.com/lang-en/snootlab-shields/135-deuligne.html

You may find that you can adapt the C for this library to work with your Arduino sketch if the messages are different.

I tried this library, and its own Hello World demo gave me an error message at compilation:

C:\Programs\Arduino\libraries\Deuligne/Deuligne.h:68: error: conflicting return type specified for 'virtual void Deuligne::write(uint8_t)'

C:\Programs\Arduino\hardware\arduino\cores\arduino/Print.h:48: error:   overriding 'virtual size_t Print::write(uint8_t)'

If I could make the display respond at all, I imagine that would be about half the work of the entire project done.

I don't have time now to learn enough about C++, as distinct from C, to have a reasonable chance to correct this code, so:

The remaining question is whether it is better to write the display initialisation and subroutines to write to the display in Sketch, or whether it is better to wire in an ISP header and program it all in C, building on bits of code I have already written. Have you any insight into which is more likely to work out better?

Arduino sketches are just C, occasionally using C++ but only as libraries. Also, if you have written functions in C, you can just paste them into your sketch.

I would forget about trying to integrate any of you other code until you have got the simplest possible hello world example working with just the screen and an Arduino board.

If you have the datasheet for the I2C screen and know what kind of messages it expects, then use the Arduino Wire library (http://www.arduino.cc/en/Reference/Wire) to send it those messages.

Absolute noobie - please accept my ignorance - looking to learn. Question regarding results of Uno and LCD w/I2C Controlled + Keypad Shield kit (Adafruit PID# 772)

Assembled LCD assembly w/o any apparent problems. Shield sits well ontop of UNO.  Uploaded the Adafruit specified "Hello World" sketch. Upon applying power (8x1.5 alkaline AA) the LCD screen lights a bright blue for app 0.5 sec then goes dark.  The words "Hello World" display faintly, along with the counter which increments 1 per second.

Question one:  Is the blue background that initially displayed, supposed to remain lit?

If I press the "Select" buttion, the blue screen illuminates, the word "Select" is displayed, and the counter continues to increment.

Question 2:  Is this what is supposed to occur?

I'm sure there are more queries to come, but need to wrap my head around this first.

Thanks.

Ken

Welcome to The 'Duino Zone.  The chances of finding someone to help with experience with your exact equipment or probliem is much greater over at the vendor's forum.

Even LadyAda endorses this policy when she says: "If you need help getting other LCDs to work, please contact the place you purchased it from, they'll be happy to help!"

Photo

Important Info

Never the less, I will endevor to assist you. Point number ONE:  Zee little orange pot on zee right hand side is for adjusting zee contrast of zee LCD display screen.  You should gently  adjust it as needed.   Point number TWO:  One or more of your batteries could  be bad, which usually results in diminished voltage level and/or current capacity.   Point number THREE:  According to the data sheet for the HD44780 you are over driving the display voltage wise.  It says: Power supply for LCD drive VCC –V5 = 11 V (max).  That might be confusing but the other way that is said is easy to understand:  Wide range of liquid crystal display driver power is 3.0 to 11V Your battery power pack is 8*1.5=12 V.  I would find a way to cut back on the voltage a bit; I think it will help the display to last longer.   Point number FOUR:  The data sheet for the I2C port expander chip makes mention that the chip will function as intended when the circuit design meets these requirements: Operating voltage: - 1.8V to 5.5V @ -40°C to +85°C - 2.7V to 5.5V @ -40°C to +85°C - 4.5V to 5.5V @ -40°C to +125°C And I don't see any voltage regulator chips installed on that shield.  The user guide should have indicated to you the appropriate input voltage.   Point number FIVE:  IMHO, optimum care and feeding of this shield calls for 4.5 volts.  That is only three 1.5 volt cells and the shield will even function reliably under most conditions with only 3 volts.

And just so you know:

-=Syntax Matters=-

See that little trimmer above the switch. Turn it with a screw-driver it should adjust the screen contrast.

Did you load a sketch onto your Arduino? What were you expecting it to do?

As to the other questions - Billabot is right - join the Adafruit forum, they are pretty good.

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