Help with arduino/motor shield issue....

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sficarro2001
 
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Help with arduino/motor shield issue....

Post by sficarro2001 »

Hi,

I’m worried there may be an issue with my motor shield and wondering if anyone can help…

I’m using an Arduino Uno R3 (Atmega328 - assembled) with the Adafruit Motor/Stepper/Servo Shield for Arduino v2.

When I use just the Arduino without the motor shield attached, I can read the state of pin D2 (toggled with button) no problem (code and setup as shown http://arduino.cc/en/Tutorial/DigitalReadSerial).

When I attach the motor shield and follow the DC motor example (https://learn.adafruit.com/adafruit-mot ... l-software) the motor turns on and runs as expected.

So far, so good!!

However, when I try the digital serial read project with the motor shield attached (same code/setup except using breakouts for D2, 5V, GND on the motor shield instead of directly from the Arduino), the state of D2 appears to randomly jump around and is not changed by pushing the button.

Sometimes the state changes/jumps if I pick up or move the Arduino/shield unit. The same behavior occurs if I try switching the read pin (i.e. to D7, D3). When I take the shield off and run the same code, everything works fine again. This suggests to me either 1) I may have messed up when I soldered the headers onto the motor shield and there is a short somewhere or 2) adding the motor shield affects the ability to use digital inputs? I was wondering if anyone had any ideas about this.

Thanks!
--Scott

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adafruit_support_bill
 
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Re: Help with arduino/motor shield issue....

Post by adafruit_support_bill »

The shield itself should not affect reading on any of the digital pins. Please post photos showing your soldering to the shield.

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sficarro2001
 
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Re: Help with arduino/motor shield issue....

Post by sficarro2001 »

I installed the headers as described (first section Installing Standard Headers, https://learn.adafruit.com/adafruit-mot ... ll-headers). Once soldered, the standard breakouts now end in solder globs. Looking underneath the motor shield, it looked to me like traces ran from D0-D7 to the immediate nearby pads as for all arduino pins, (D0-7, D8-SCL, IOREF-VIN, A0-5) there appear to be nearby empty pads. I just assumed there was a 1:1 translation for all pins for easy install of connector blocks... using the voltmeter this is the case for +5V, +3.3V and GND. However, this does not appear to be the case for D0-7; when I jam the wire meant for D2 (from the digital read project) on the D2 solder glob (but not the nearby pad with newly installed connector block) everything works as it should. So, main problem solved, but I'd like to ask, what is the best way for reversible connections to D0-D7 on the motor shield if you've installed the standard header blocks (right now there is just solder on the pin sticking through)? If I could re-do this, I'd install the stacking system!

Thanks!

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Franklin97355
 
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Re: Help with arduino/motor shield issue....

Post by Franklin97355 »

Could you post clear, detailed pictures of both sides of your board showing any soldering you have done and the connections to it?

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adafruit_support_bill
 
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Re: Help with arduino/motor shield issue....

Post by adafruit_support_bill »

However, this does not appear to be the case for D0-7;
If you look at the back of the board, you will see that these are indeed connected to the corresponding pins. Please post photos showing your soldering.

Image

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sficarro2001
 
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Re: Help with arduino/motor shield issue....

Post by sficarro2001 »

Here are some (hopefully!) relevant pictures. Solder looks a bit thin on D2, but I did try other pins as well. Any insight much appreciated!
Attachments
100_3378.JPG
100_3378.JPG (240.98 KiB) Viewed 474 times
100_3381.JPG
100_3381.JPG (283.94 KiB) Viewed 474 times
100_3390.JPG
100_3390.JPG (341.49 KiB) Viewed 474 times

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adafruit_support_bill
 
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Re: Help with arduino/motor shield issue....

Post by adafruit_support_bill »

Many of your solder joints (D2 in particular) have not flowed onto the solder pad. The cross-section should look like the diagram below:

This guide has tips on identifying and fixing problem solder joints: https://learn.adafruit.com/adafruit-gui ... n-problems

Image

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sficarro2001
 
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Re: Help with arduino/motor shield issue....

Post by sficarro2001 »

You were right - I simply checked resistance b/w header pin and my connector block - open! After dropping more solder on, good to go! Thanks for the solder guide, very useful.

And thanks for all the help!

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