I have been doing some research on combining three products. I would like to put the following 3 things together.
First I checked if there are any conflicting pins,
Arduino GSM Shield uses pins 2(gsm rx),3(gsm tx), and 7(modem reset).
Adafruit TFT 2.8" TFT Touch Screen uses pins 9-13(display), 8(touch), and 4(sdcard).
So I should be good with the 2.8" screen in the pin out department.
Next, I check the requirements to power each device.
Arduino GSM Shield overview page says that it is not recommend to use USB power as it is not sufficient enough to handle peak usage. Peak usage can draw up to 2A. It is recommend to use a power supply that can prove between 700mA and 1000mA.
Adafruit TFT 2.8" TFT Touch Screen description said "Onboard 3.3V @ 300mA LDO regulator, current draw depends on usage but is about 100mA for the display and touchscreen". Little confusded here but I think it uses 100mA, please correct me if I am wrong.
And then my thoughts on the physical build are based on a video I saw on Arduino Youtube page.
If you look at the screen shot of the video above, you can see that the presenter connected the Uno Board underneath the GSM Board... and still has more pins available on the other side of the GSM shield. I was wondering if it is possible to mount the TFT LCD from above on the other side of the GSM shield? Kinda of like a sandwhiching them all together then connecting it to a power supply.
Now I tried to google stuff like "How to combine Arduino Boards", "Stack Arduino Boards", etc. But Couldn't find anything. My guess is that you unsolder the current pins on it and replace it wih some sort of a double sided pin.
My questions and concerns, which brings me here. Hopefully someone with more knowledge on the subject could help me out here.
1.) What kind of external power supply will I need?
The GSM required 700-1000mA and LCD requires 100mA. The Uno product overview recommend to use a 7-12V power external power supply. I am un-familier with the measurements so I am not sure what to get for the power supply. Should I be looking for 9-12V? Will that be too much?
2.) Is the sandwich build possible?
I know the Uno and GSM would attach ok, but will I be able to attach that touch screen to the other side?
3.) Will the pin out on 3.5" screen be the same as 2.8" screen?
I could not find the pin out like I did on the 2.8" screens product overview, or maybe the terminology used went right over my head. I assume it would be the same, but I would just like to confirm with someone else before I did get it.
Thanks for reading guys, I'm sorry about the long write. I tried to make it a little more visually appealing for your reading pleasures, lol. So any thoughts of this build will work?