classroom demos with standalone network access

[sgbaird]

First, you should check with your institution to see if they have a 2.4 GHz WPA2 network option (for example, University of Utah has a network option for this geared towards IoT-style devices, but University of Toronto doesn't allow WPA2 connections). If the institution doesn't support that, then it's probably best to go with one of the WiFi hotspot options from #83.

Alternatively, you can have students use WiFi hotspots from their mobile devices. If using a phone's mobile hotspot, you may need to turn on "extend compatibility" or "maximum compatibility" settings to make sure it's a 2.4 GHz WiFi signal that you're sending out. Likewise, on some devices (e.g., iPhone), you may need to turn off "Limit IP Address Tracking".

Some access points (phone mobile hotspot, router, etc.) may impose limits on the number of devices that are allowed to connect. It's not clear which ones give a maximum number of connections as a recommendation (based on splitting bandwidth) and which ones give it as an upper limit (somewhat arbitrarily) imposed by the device.

Note that whatever device is used should support 2.4 GHz.

Recommendations

This is based on the summary of options I collected in #83 (comment). Note that data transfer is likely to be fairly low in a classroom setting, so the lower fixed costs options are preferable. For a lab setting with many devices connected and frequent communication, the higher fixed cost and lower data rate is preferable.

Up to 15 Students/Teams/Devices

• Hologram Global IoT SIM Card ($5.00 + $8/100 MB) + Alcatel Link Zone 4G LTE Mobile Router ($59.99)

OR

• KeepGo Mobile Hotspot ($129 + $3/100 MB)

Up to ~30 Students/Teams/Devices

• Hologram Global IoT SIM Card ($5.00 + $8/100MB + $0.70/month/device) + (Cudy N300 Router ($89.90) OR Alcatel Link Hub Router ($82.99))

[sgbaird]

WPA Enterprise MicroPython example at https://raspberrypi.stackexchange.com/a/140111/137101

EDIT: based on the MicroPython docs it doesn't seem like this is implemented within network, but maybe still worth trying.

[sgbaird]

Thoughts on using blues.io

One option is to go with a https://blues.io Raspberry Pi starter kit, connect it to a Pico W that acts as a receiver for other Pico W's in the room, and get the Pico W's to communicate with each other (assuming it's possible to directly communicate between Pico W's without an external WiFi network). This way, you don't have to worry about people misusing WiFi and potentially consuming a lot of bandwidth.

The main thing is how an instructor wants students to interact with the demo. It differs somewhat from a prototyping environment, where it might make more sense to go with one of the prepackaged options in #83 like https://www.amazon.co.uk/dp/B016ZWXYXG/ + an appropriate SIM card or https://travelwifi.com/portable-hotspots/sapphire-2 since the concerns about misuse might be less. Of course, if there's a WiFi network that the Pico W can connect to directly, even better - and if that involves MAC spoofing (assuming it doesn't violate terms of service), then that avoids the need to host a separate WiFi network (hotspot).

To have a set of 10+ demos in a single classroom (with perhaps groups of 2-3 students) and given the constraint of the Pico W that it can host up to 4 clients as an access point, either there needs to be some finagling of connecting and disconnecting from the network (i.e. only 4 "allowed in the room" at a given time) or setting up multiple Pico W's that act as access points.

Maybe better at that point to go with https://www.amazon.co.uk/dp/B016ZWXYXG/?th=1 and a prepaid cellular IoT sim card (e.g. IoTDataWorks, ThingsMobile, Hologram), especially since then all students can connect to the same network.

Sparrow DevKit (i.e. going with a LoRa gateway) is another option.