Hello, has anyone else been having occasional trouble being able to connect to the RACHEL-pi WiFi from a raspberry pi 4 and/or have any recommendations on how to fix this problem?
Thanks.
Hi @acedillo
Is this using the latest 32bit image? I haven’t heard of any issues, but there can be interference if you’re using a USB drive to boot with the Pi4 rather than a MicroSD card. Do you have more information around what you’re seeing?
James
Hi James, Thanks for your response. It’s using the 64bit experimental image, and it is using the USB drive to boot. Have you by chance heard of any ways to get around the interference of using the USB drive to boot (other than hosting the content on an SD card instead)?
Hi @acedillo - You should at least be able to initially connect to the wifi when booting from USB 3.0. It’s possible you’re having issues due to low voltage. You won’t see low voltage errors in terminal over SSH, but you will when the device is booted with a monitor connected.
Outside of design flaws in the board itself, any interference would probably be with the 2.4ghz band. It’s possible switching to 5G is a solution. The hostapd.conf file settings can be changed to 5G.
There is a new RaspiOS available so I will be looking at this new images this week. 64bit has always been experimental from the Raspberry Pi Foundation’s releases, so hopefully they’re more stable now. I’ll give the option for 5G in an updated image that you can try.
James
Thank you. We will look into seeing if the issue is from low voltage. And definitely we will try your new image file once you have released that. Thanks!
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Hi @jamesk, I wanted to follow up on this thread with a separate issue that our team has been encountering when using RACHEL with the raspi 4’s hotspot. When we do connect to the RACHEL hotspot from an rpi 4, we’ve noticed that it very consistently caps out after being connected to on only 6 devices. Do you have any ideas on why it cannot support more than 6 devices at one time? And/or do you have any suggestions on how we can increase the number of devices that are able to connect to it (for example, do you have any specific USB WiFi adapters that you would recommend for the device)? Thanks.
Hi @acedillo - I want to give you a heads up that the new images ( 64bit included ) are delayed due to another issue with creating wifi hotspots that has shown up in the latest RaspiOS ( dhcpcd blocking SSID broadcasting… ). Unfortunately each OS update seems to make the Raspberry Pi a worse option for projects that create hotspots. I am working on a fix.
From my understanding, the driver that is provided to the Raspberry Pi Foundation from the manufacturer of the wifi chip is the limitation on the user count. They are storing a list of associated MAC addresses within the chip’s memory and as more clients connect, less is available. At some point it resulted in wifi crashing, and now I believe they just set a limit lower and lower. For some versions it was 8 clients, for the 64bit image it must be 6. The Raspberry Pi Foundation have said they don’t have a way to get them to fix this. There’s a post about it here https://github.com/raspberrypi/linux/issues/3010 that has been ongoing for some time. There is an option in there now that has an alternative firmware, https://github.com/RPi-Distro/firmware-nonfree/tree/bullseye/debian/config/brcm80211/cypress. I would try installing that to see what happens. When things are up and running I’ll create images with that firmware too.
I have only tried adapters that are from Amazon ( Tiger branded ) and had to build the drivers manually to get it supported. I suggest trying any adapter that’s being sold specifically for Raspberry Pis. For 2.4ghz Edimax are the ones that work the best
James
Thanks so much for all this info, James. Really appreciate it.
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I hope that helps testing the existing images. Unfortunately I don’t have an update on the other new images yet. I may have to restructure how the network works on RACHEL-Pi to get around the issue.
If you do try that driver with the older images and a 5ghz hostapd configuration let me know.