4 Replies Latest reply on Sep 5, 2019 6:53 AM by linuxengineer

    Power Raspberry Pi and Access Point

    mike400hp

      I am working on a project where I want to integrate a Raspberry Pi and a wireless access point into the same enclosure.  The AP came with a power supply with a output rating of 12V ... 2.0A.  What I am looking for is assistance designing a small board that will take power from a wall plug AC adapter and split it out so that I can power the wifi board and the Raspberry Pi from a single plug.  Here is a very rough sketch. 

       

      Screen Shot 08-20-14 at 10.52 AM.PNG

      I need the custom built board to be small and provide as clean of power as possible.  I'm going for reliability.  Anyone have an idea how to get this done?  I would even consider commissioning this work out to someone who is looking for a project.

        • Re: Power Raspberry Pi and Access Point
          shabaz

          Hi Michael,

           

          There are off-the-shelf modules that will take the wall plug adapter voltage (make it a 12V DC wall adapter) and convert to 5V for driving the RPI. The AP can be powered directly since it is 12V. So, in summary you'll only need one wall adapter running into the overall enclosure as you mention.

           

          See these DC-DC converter modules, most of these are suitable. Try to allow some headroom in case the RPI has any ancillary devices plugged into it's USB ports that consume power. So (for example) a 5V 2A DC-DC converter may be more suitable.

            • Re: Power Raspberry Pi and Access Point
              mike400hp

              That makes sense.  The WiFi AP came with a 12v 2amp AC adapter.  I wonder if I can solder the DC-to-DC regulator onto the back of the PCB of the AP where the power supply pins come through.  What are your thoughts on the amps?  If the AC adapter is giving me 12V and 2amps, do you think I can run both the RPI and the WiFi AP?

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                • Re: Power Raspberry Pi and Access Point
                  shabaz

                  Hi Mike,

                   

                  The voltage is important, the devices will consume the appropriate current (amps). You need to ensure that you deliver 12V (and 5V through the DC-DC converter) with a sufficient capability so that the AP and RPI devices will be able to consume the current (amps) they need. Higher capability is ok for your supply, but lower is not. 12V 2A sounds low to be honest but it might work. I'd go for 12V 3A or 4A which gives you plenty of margin.

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              • Re: Power Raspberry Pi and Access Point
                linuxengineer

                I opensourced on Github a (largely) self-configuring AP that works with a Pi 3B+ and Pi 4.  Here's the link for the Element14 Project Page:

                 

                Raspberry Pi Access Point

                 

                Really just need a pi, Internet connected router with a free port enabled for DHCP and an Ethernet cable to uplink the Pi to the router. And of course my Github repo "pi-ap" and off you go.  Only thing you might need to change is the DHCP subnet if the default (192.168.0.0/28) clashes with an existing subnet on your LAN.  HTH- Terrence Houlahan

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