Hardwired Ethernet and WiFi in same project

I am currently looking at some options to interface a fingerprint access system to my network. The device has an Ethernet port but I don’t want to run a cable from this to the router so I was thinking I could make a bridge device with a Cobra 3 and add WiFi and Ethernet to this.

The Ethernet port would be fixed IP and use a cross over cable. WiFi would be DHCP.

I want to capture the packets over the Ethernet port. The fingeprint device sends out UDP messages each time someone uses it. I will decode these and resend MQTT packets to the WiFi network for Node-red to handle the status of each user.

Should I use a different IP range for the Ethernet? eg, my main network is on 192.1678.1.x and I would put the Ethernet on 192.168.2.x or should I keep them the same and simply used a fixed IP for the fingerprint device and the Cobra 3 Ethernet that is outside the DHCP range setup on the router?

Has anyone done something like this and can confirm that this idea would work?

With the builtin TCP Stack in NETMF you can only use one Physical Interface with one IP address.
If you Need a 2nd Interface, you have to use one with an Serial Interface (like rs232, SPI, …) that Comes with an seperate Driver.
Ideally this 2nd Interface has it’s own onboard TCP stack.

I hope a 2nd IP or even a 2nd Interface will be supported by TinyClr at some Point.

Now that we have TinyClr, can’t we just do that?

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Looks like the Rasberry Pi might be the only solution in the short term. At least I think this supports both at the same time. My weekend project to check it out.

@ Dave McLaughlin - Let me see if I understand the Architecture:

Fingerprint device is attached via ethernet.
You want the device to be attached via WIFI.
You need to convert the fingerprint device’s data from one format to another.

If I understand correctly, then you could use a WIFI to ethernet bridge to put the data on the wifi network, then have “something” convert the fingerprint data that is broadcast into the MQTT that you desire.

If I could find a low cost off the shelf solution to do the Ethernet to WiFi then yes, that would work.


How low is low cost?

if you can find an old TP-Link device (in the $20-30 range) that will run DD-WRT, that would do… cheap on power too. Otherwise something like a wrt54g would also be ok but I’m sure it’d use more power…