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It is possible to stack two different Add-Ons in Raspberry Pi 3?
Posted: Tue Nov 14, 2017 12:08 pm
by jfcmartins
HI! I need to create a project that has GPRS/GSM and GPS, but there are no products with both functionalities. I found some Add-Ons that may work but I'm not sure if there is any way to stack both. I know that is impossible to put one on top of each other because there aren't compatible. The products are:
There is any way to stack this Add-Ons in Raspberry Pi 3 Model B?
Re: It is possible to stack two different Add-Ons in Raspberry Pi 3?
Posted: Tue Nov 14, 2017 1:05 pm
by DougieLawson
Re: It is possible to stack two different Add-Ons in Raspberry Pi 3?
Posted: Tue Nov 14, 2017 1:10 pm
by hippy
Both seem to use UART for communications so, if both use the same UART pins on GPIO, that will be an issue. You will either need to use separate UART connections, or provide a means to only electrically connect one board at a time to the UART pins.
You may be able to stack them by modifying one of the boards to re-route tracks or perhaps by adding an intermediate board in the stack.
Re: It is possible to stack two different Add-Ons in Raspberry Pi 3?
Posted: Tue Nov 14, 2017 2:00 pm
by scruss
what for you ask identical question on stack exchange? It's kinda rude to go NEED ANSWER NOW from volunteer communities:
pi 3 - It is possible to stack two different Add-Ons in Raspberry Pi 3? - Raspberry Pi Stack Exchange
As I said on RPSE, boards based on other chipsets such as the SIM908 combine GSM/GPRS and GPS on one module.
Re: It is possible to stack two different Add-Ons in Raspberry Pi 3?
Posted: Tue Nov 14, 2017 2:46 pm
by fruitoftheloom
Re: It is possible to stack two different Add-Ons in Raspberry Pi 3?
Posted: Wed Nov 15, 2017 10:36 am
by jfcmartins
With that product I can run both Add-Ons at the same time? I want to make a project that receives the coordinates (GPS) and send to a server (GSM/GPRS)...
Re: It is possible to stack two different Add-Ons in Raspberry Pi 3?
Posted: Wed Nov 15, 2017 10:37 am
by jfcmartins
I'm sorry. I didn't know that I can't post on both sides... But thanks anyway for the sugestion
Re: It is possible to stack two different Add-Ons in Raspberry Pi 3?
Posted: Wed Nov 15, 2017 10:37 am
by jfcmartins
That's a nice product but it's too expensive for what I'm looking for
Re: It is possible to stack two different Add-Ons in Raspberry Pi 3?
Posted: Wed Nov 15, 2017 10:38 am
by DougieLawson
jfcmartins wrote: ↑Wed Nov 15, 2017 10:36 am
With that product I can run both Add-Ons at the same time? I want to make a project that receives the coordinates (GPS) and send to a server (GSM/GPRS)...
That's the way I see Alex Eames' latest product. I've bought one to free up the GPIO pins on my RPi2B which has a BT/WiFi pHat on it.
Re: It is possible to stack two different Add-Ons in Raspberry Pi 3?
Posted: Wed Nov 15, 2017 10:55 am
by jfcmartins
DougieLawson wrote: ↑Wed Nov 15, 2017 10:38 am
jfcmartins wrote: ↑Wed Nov 15, 2017 10:36 am
With that product I can run both Add-Ons at the same time? I want to make a project that receives the coordinates (GPS) and send to a server (GSM/GPRS)...
That's the way I see Alex Eames' latest product. I've bought one to free up the GPIO pins on my RPi2B which has a BT/WiFi pHat on it.
Thanks! I think that might work on my project. The only thing that concernes me is if with the two boards I posted are compatible with the FullpHAT. There's space for the two boards in the FullpHAT?
Re: It is possible to stack two different Add-Ons in Raspberry Pi 3?
Posted: Wed Nov 15, 2017 11:39 am
by hippy
jfcmartins wrote: ↑Wed Nov 15, 2017 10:55 am
The only thing that concernes me is if with the two boards I posted are compatible with the FullpHAT.
They might not be if your two boards are expecting to use the same UART pins ( as previously noted ) unless the FullpHAT caters for doing that. I don't know; you'll have to read the documentation.
Re: It is possible to stack two different Add-Ons in Raspberry Pi 3?
Posted: Wed Nov 15, 2017 6:34 pm
by scruss
jfcmartins wrote: ↑Wed Nov 15, 2017 10:37 am
That's a nice product but it's too expensive for what I'm looking for
USB serial GPS, then? Won't have the fancy clock features that GPS hats have, but will work with GPSd. Also, really cheap.
GSM/GPRS modules can draw a huge amount of current when they start up, btw.
Re: It is possible to stack two different Add-Ons in Raspberry Pi 3?
Posted: Thu Nov 16, 2017 10:37 am
by jfcmartins
scruss wrote: ↑Wed Nov 15, 2017 6:34 pm
jfcmartins wrote: ↑Wed Nov 15, 2017 10:37 am
That's a nice product but it's too expensive for what I'm looking for
USB serial GPS, then? Won't have the fancy clock features that GPS hats have, but will work with GPSd. Also, really cheap.
GSM/GPRS modules can draw a huge amount of current when they start up, btw.
Yes, that's one of the possibilities... I found one very interesting (
https://www.amazon.com/GlobalSat-BU-353 ... rds=BU-353) but the priority is to find a board to put the entire device in a case.
So the Raspberry Pi will get slow when I use the GSM/GPRS module?
Re: It is possible to stack two different Add-Ons in Raspberry Pi 3?
Posted: Thu Nov 16, 2017 11:18 am
by hippy
jfcmartins wrote: ↑Thu Nov 16, 2017 10:37 am
So the Raspberry Pi will get slow when I use the GSM/GPRS module?
I don't see why it would. There will always be some impact when the Pi has more to do but unless it were being hammered with data I would not expect it to slow down drastically.
Re: It is possible to stack two different Add-Ons in Raspberry Pi 3?
Posted: Thu Nov 16, 2017 5:10 pm
by scruss
jfcmartins wrote: ↑Thu Nov 16, 2017 10:37 am
So the Raspberry Pi will get slow when I use the GSM/GPRS module?
Not slow: just you need to have a power system that can supply 1 amp or so to the GSM/GPRS module on top of providing whatever your Raspberry Pi needs. If that power's not available, your Raspberry Pi will likely shut down unexpectedly.
I recently worked on a project with GSM-based Electron boards, and while they're a pretty low-power ARM microcontroller, their phone startup current is about 800 mA.