Action Item #614


Find the right Wifi dongle for combine AP / client mode use

Added by Hammel about 6 years ago. Updated over 5 years ago.

Target version:
Start date:
26 Mar 2018
Due date:
% Done:


Estimated time:
01 - Critical


The monitor (re: RPi w/ PiBox) needs a wifi module capable of both AP and client mode. To verify the module supports this, run iw list and check for the valid interface combinations section. It should look similar to the following.

valid interface combinations:
         * #{ managed } < = 1, #{ AP, P2P-client, P2P-GO } <= 1, #{ P2P-device } <= 1,
           total <= 3, #channels <= 2

The important bits here are the managed and AP entries, which signify that the module supports both. Also, if channels > 1 then the AP and client can run on different channels. Otherwise they have to run on the same channel.

Actions #1

Updated by Hammel about 6 years ago

  • % Done changed from 0 to 10

Aside from the dongles already listed in usbhandler.conf from PiBox core, I found the following which may prove useful.

Also, the TP-Link WN821Nv2 I already have, which is not a nano adapter, should be tested next since I think any Atheros adapter should work.

Note: I think an adapter with an antenna (or even two, if there are two radios) would be best for picking up remote sensors. The problem appears to be that some WiFi dongles require the use of an external hub to operate correctly because they draw so much power. That may explain why they didn't work so well in my demos at Maker Faire.

Actions #2

Updated by Hammel about 6 years ago

  • % Done changed from 10 to 20

A bit of research on the state of wifi dongles for the Raspberry Pi shows that the Pi Model B had issues with dongles and that it usually required an external powered hub to work correctly. Other models also have this problem but to a lesser extent. The Model 2 and later seem to be much better about this.

This may explain why early development had such a hard time with the wifi dongles when demo'ing at the Maker Faires.

Actions #3

Updated by Hammel almost 6 years ago

  • Priority changed from Immediate to Normal
Actions #4

Updated by Hammel almost 6 years ago

  • % Done changed from 20 to 40

For Ironman I'm using a TP-Link TL-WN821N which allows both client and AP at the same time, but only if on the same channel. This dongle is huge but it works and I don't have time to research better options at the moment.

Also: I tried to bring up the on-board Pi 3 wifi using brcmfmac and it's associated firmware. The module loads but didn't work, at least not while I had the TP-Link installed. So more research on this is required. For now the on-board will be disabled by not loading the driver by default.

Actions #5

Updated by Hammel over 5 years ago

  • % Done changed from 40 to 100

The problem with the dongles wasn't the dongles but power issues with USB ports on the Pi's. I managed to fix this by resoldering the server's power switch and using a power supply known not to give the firmware's low voltage warnings. And a micro-WiFi-dongle worked just fine for this.

This is sufficient for this issue. I can get around to the onboard WiFi on the Pi 3's and Zero's at some future time.

Closing issue.

Actions #6

Updated by Hammel over 5 years ago

  • Tracker changed from Test Status to Action Item
  • Status changed from New to Closed

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