Arduino 5 Minute Tutorials: Lesson 8 - Wheatstone Shield & LCD

@emtiyaz If you have design related questions, feel free to post a new topic on the RobotShop Forum

I get this error message when I try to upload the program on the arduino software:
C:\Users\Mattias\Documents\Arduino\libraries\Wheatstone-Bridge-Amplifier-Shield-master\Examples\strain_gauge_shield_and_lcd_arduino_uno_code\strain_gauge_shield_and_lcd_arduino_uno_code.ino:102:34: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings]

How do i fix this?

@Mattias Evans: We compiled the example with a fresh install of the Arduino IDE 1.6.7 and a copy of Wheatstone Bridge Amplifier Shield library and did not receive any warning or errors. If your Arduino IDE is not up-to-date, we recommend that you update it now.
Also, you may want to check this page and search for -Wwrite-strings on it. It describe the use of this warning, which is off by default for C but on by default for C++. Please note that you can simply disable or ignore this warning as it is not an error.

I can’t ignore these messages as it states that there is a problem uploading to board.

@Mattias: Blog comments are not the best place to answer complex technical issues. Please post about this on our forum here or open a support ticket here.

Any advice on this error message?
Imgur

@Raji It seems like you need to add a specific library; look for it on the Arduino website.

@ColemanBenson I have the same error but I can’t determine what is missing or wrong. Do you have any idea of what I have to installed?

@Luc What error exactly? If it’s the same as Mattias Evans, please see @scharette’s solution.

@ColemanBenson Not the same as Mattias Evans but the same as Raji: error ‘unknown type name ‘LiquidCrystal’’ on the line ‘extern LiquidCrystal lcd;’ I have opened an issue on the github’s repository (https://github.com/RobotShop/Wheatstone-Bridge-Amplifier-Shield/issues/)

@ColemanBenson In fact, I have found the error. In the example of the library, the ‘strain_gauge_shield_and_lcd_arduino_uno_code’ directory contains a ‘.c’ file. To obtain a correct compilation the extension must be change to ‘.cpp’.

@Raji, Luc: Thank you for reporting this error. A fix has been added to the GitHub (renaming to .cpp).

EDIT Comment was moved to the forum of RobotShop due to its length and technical nature. It can be found here: https://www.robotshop.com/forum/wheatstone-amplifier-shield-lcd-issue-arduino-zero-t14987.

@Lawrence: We have answered your comment on our forum (post here). Please note blog comments are meant for small clarifications of details in the article. For integration issues or other troubleshooting, please use our forum. If you received a defective part or have other complex issues, you can open a support ticket here.

You use A1 and Strain2 in the example above. The LCD shield does not seem to use A0 so would it be possible to use a switch to connect either A1 or A0 to A5 as required to show the output of both Strai 1 and Strain2, not simultaneously of course.

@Bill the 16x2 LCD Shield Kit for Arduino uses the A0 pin for buttons. That’s why we used the “bent pin” workaround to connect A0 (from the LCD Shield) to A5. With this hack, you still have access to Strain 1 and Strain 2 (A0 and A1).

Hi there,
When I follow all instructions above I get no change in raw ADC when applying a force to the load cell. Using a different example I have already made sure the ADC does change when applying a force to the load cell. Do you know why this might be?

Thanks,
Max

Hi there, when I follow the steps above to calibrate the setup and go to apply force to the load cell the ADC value does not change. When I’ve tried different examples I’ve made the ADC value change by applying a force to the load cell - so I think there must be connection issue between Arduino and LCD Shield?
Thanks

@Max Blake: Since these are technical questions, we recommend that you continue this support request on the forum. Since you already have topic there about it, we recommend that you post additional details there, such as pictures of your setup (showing clearly all components, wiring, etc.). These extra details would certainly help with identifying potential issues and solutions.

WheatstoneBridge wsb_strain1(A0, 365, 675, 0, 1000) excuse me please can i have an explanation about these values and where do they come from please