I have bought a SIM900 shield for an ordinary Arduino Uno board. The problem is that it doesn't have long pins on the bottom side, making it impossible to click on mu Arduino Uno. The shield I have is this: enter image description here

As you can see, there are identical pin spaces next to the red and yellow plastic female pin things. Can I just solder new pins in the free spaces and will it work like that? I notice that the yellow and red plastic female pin holders on my board are on the free spaces in this picture. I supposed I can just use the adjacent foles to solder long pins so I can use it for my Arduino?

  • It might be wisest to send it back, since it's not functionally an "Arduino Shield" without those. You could modify it, but if you have to do so to even try to use it, what will you do if it turns out not to work? Commented May 9, 2016 at 0:30
  • Good point... I haven't come around to soldering the pions on yet. However, it took 2 months to receive the package, I am not going to send it back to China... We'll see what happens :). Commented May 9, 2016 at 6:01

1 Answer 1


Yes, you can.

There is two methods of making shields stackable:

  1. Use the quite hard to source extra long pinned headers to go right through and down (such as these https://www.adafruit.com/products/85) , or

  2. Use separate headers and pins and (if you are using through hole) offsetting them.

Your shield uses the second method, but the descending pins haven't been populated. By populating those pins you are just completing the build.

  • Thanks, then I will solder some pins to the board so I can stack it on top of my Uno :). Commented Mar 31, 2016 at 16:12
  • You'll have to clean out the holes first. Commented May 9, 2016 at 0:31

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