Despite that I am new to Arduino, I am tasked to invent a serious alarm system and I chose Arduino. I study electronics, but virtually I am a software programmer and C is my area of expertise.

I ordered the parts I think I will need and the time is immensely pushing me. The delivery goes slow and it needs to happen before our planned vacation, because we've been robbed several times so far. I need to know if I will need another gadgets to deal with a problem I've discovered suddenly.


I plan to stack up these 3 shields

  1. Arducam-F Shield V2 Camera module shield /w OV2640
  2. 3.5" TFT LCD Display Touch Screen Module
  3. SIM900 Quad-band GSM/GPRS Shield

From what I've learned the shields 1 and 3 are compatible, as the arducam uses CS/SD, ICSP, VCC, GND, SDA and SCL or according to standard pin out table: I2C_SCL, I2C_SDA, SPI_SCLK, SPI_MISO, SPI_MOSI, 9, 10, Reset, 5V, GND and the GPRS shield uses D7 and D0/D1(or D2/D3), 3 I/O ports. For D7.

The arducam however seems to be not stackable and as far as I can not see it is impossible to make it stackable (Maybe even if I drill holes and solder stackable shield headers) So it must be the topmost shield.

What about the LCD shield? I also learned that such shields use a lot of pins, so it is possible that there will be no free pins. I also ordered lots of jumper wires of any kind, if that can help. Maybe I don't need to wire each of the pins in order to make it work or do some extra coding to get it work? I also don't necessarily need the other shields to work while I operate with the screen, so maybe there is a way I can connect/disconnect shields separately with a program or something else I can buy. I have a feeling that this LCD shield will leave no pins for the other shields and I should connect the arducam on another way since it is not stackable.

  • 5
    I don't want to disappoint you, but it seems a lot is at stake (robberies). Are you sure if you are new to Arduino / electronics, to create something critical in a short time, instead of buying a (probably more expensive) solution? Commented Jun 22, 2017 at 11:23
  • I agree with @MichelKeijzers that IF this project is for protection of a building then its a stupid idea. You should be able to purchase a commercial system with at least the same capabilities for not much more than you have already spent. I see the attraction in doing it for fun, but not for real. Would you operate on someone to remove their appendix? No, you don't have the skills and its unreasonable for someone to think you can jump into another field and just start achieving stuff. Commented Jun 22, 2017 at 11:32
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    @CodeGorilla What if I buy second arduino, optimized for the screen only and connect it to the main arduino creating I2C bus. I also bought motion sensor as a condition to activate the camera, I bought 4 li-ion lg batteries for independent power supply.
    – Edenia
    Commented Jun 22, 2017 at 11:52
  • 2
    @Ediana ... I hope you can finish it in time, I also have a 'hobby' project in mind, but it will take much longer than expected, but of course it's fun. I wish you all good luck (and see you already have tips/answers from others). Commented Jun 22, 2017 at 11:57
  • 1
    Comments are not for extended discussion; most of this conversation has been moved to chat. (cc: @MichelKeijzers) Commented Jun 23, 2017 at 22:51

1 Answer 1


Its not just a question of the stackability of the shields and the clash of pins you also need to consider what the shields do.

Stacking the GSM shield under the LCD is going to restrict is tx/rx power unless you have an external aerial.

The LCD will require a large amount of memory and processing power, a 3.5" inch display is really going to push an Uno to the edge, you aren't going to get much time for servicing the GSM and camera.

The camera is also going to require a large amount of RAM and processing time to handle still images. If you are processing video then I really doubt you will be able use the other shields.

You don't say if you are experienced in Embedded development. Its different to Linux or Windows dev where resources are almost limitless. If you don't have experience then you might find the transition quite hard.

Your question was are they compatible, I don't have the evidence but I would say no because of the resources they consume. Sorry I can't see this project going anywhere fast. :(

  • Code Gorilla, thank you for your help. I don't particularly have experience in embedded programming, but I have experience in something very similar - optimizational programming - using as little resources as possible (in terms of memory and performance)
    – Edenia
    Commented Jun 22, 2017 at 12:01
  • I think it should do, because I don't need all shields working in the same time. On the contrary, It occurs that I will use one in event.
    – Edenia
    Commented Jun 22, 2017 at 12:02

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