Simple Ethernet Board with Register

Yes, that is certainly an option, a good one :-)

Cheers

Klaus

It will be running in a loop, I may need a regulation loop for humidity control etc. I have not yet decided if the node just transfers the data to a central node that has the necessary logic or that each node is self sustained

I have done visual C, labwindows, embedded C and a little HTML programming.

I would like to add a grapic interface for the control logic. What would be a good choice of app for that?

Cheers

Klaus

If you are talking about multiple nodes in different places, then RF might be a better choice than Ethernet. OTOH, serial might be cheaper if you don't need Ethernet speed.

It's nice, good price. I have extensive experience with the STM32, so I think the ENC28J60 module could be a good fit

Cheers

Klaus

I have ethernet in almost all rooms. I have considered wireless but am worried about security and availability issues. With ethernet I can do PoE if the Phy supports it.

But wireless is certainly easier when I need to expand it.

Cheers

Klaus

doesn't look like he is selling, but there's code

-Lasse

Very nice board :-)

Cheers

Klaus

Yes, security is always a concern. We will have AES128 on the devices. Key distributions will be a major issue. However, unlike Bluetooth, we don't have to pair arbitrary devices. We can have time sequenced one-time keys stored on both devices.

Since we can reprogram all the devices in this "closed" net at the same time, we can just tell them to ignore all other devices. The master node can also redistribute the key file on the fly.

If you put your devices on the Ethernet (and consequently Internet), you have a bigger security risk with your wired net than our wireless net.

That's true, if the ethernet is not encrypted. The key file is a pain, if you don't program it in fixed from the start, then it's easier.

Cheers

Klaus

A piece of twisted-pair Ethernet cable supports up to 7 relays; use relays with (say) 5 V coils and feed the cable with 6 V or 9 V or whatever you need to overcome the voltage drop. (Watch out for the current in the return wire.) If you later need more than a relay at a location, you can unplug the Ethernet cable from the relays and the relay driver and plug it into a real Ethernet port.

Or, use RS-232 or RS-485, which pretty much every microcontroller already supports. Use one pair in the Ethernet cable for serial data and another for power. Again, when it's time to upgrade to "real" Ethernet, just unplug the cable and swap.

If you only need to drive one relay, and the PHY provides the "link LED" function, wire the relay coil to the PHY's LED output. Then, disable or enable the Ethernet port at the other end under software control; then you need zero code on the microcontroller next to the relay. :) (If the PHY also provides a 10/100/1000 LED output, and you can control that on the other end, you can run more than one relay.)

Matt Roberds

If i understand it correctly, the existing cables are running IP over Ether net (and thus Internet). That's the reason of OP's choice of Ethernet boar d. It may or may not be a good idea. But as long as he is doing so, his d esign must co-exist with IP, including but not limited to, DHCP, TCP and UD P, etc.

If we are free to pick the media (Cat-3,4,5,6), then i choose none and go w ith RF. Power is likely available close to whatever equipment he is contro lling anyway.

How about a MPS430 ? $35, Looks like a CS8900 on it and lots of I/O.

Cheers

ernet (and thus Internet). That's the reason of OP's choice of Ethernet bo ard. It may or may not be a good idea. But as long as he is doing so, his design must co-exist with IP, including but not limited to, DHCP, TCP and UDP, etc.

Correct, the usage of the cabling can only be in the extend that only 4 wir es are used for 100BaseT and below, so if I upgrade to 1000BaseT it conflic ts with the usage of wires.

Cheers

Klaus

Not the main code, the USB Class driver for the USB-to-Ethernet adapter. I only see USB to serial in the CDC.

Best regards,

--sp

There is a TCP stack library and a USB host library. Your main code call t he host functions for USB emulation. Within the USB library functions, you need to put in hocks to call the TCP functions. But you also have to deal with the unique USB chip set. So, it's doable but still lots of work.

We were heading that direction, but switched to RF instead. It's a lot sim pler to just SPI the RF chip (MRF24J40).

How about this:

I have driven this board with an AVR Mega328P, but anything that does SPI will work. Al told, you'll end up with about $5 worth of parts, and a half-hour or so to build, if you're doing more than one. Then you'll need a relay.

In

Ethernet (and thus Internet). That's the reason of OP's choice of Ethernet board. It may or may not be a good idea. But as long as he is doing so, his design must co-exist with IP, including but not limited to, DHCP, TCP and UDP, etc.

go with RF. Power is likely available close to whatever equipment he is controlling anyway.

The use of Ethernet does not imply a connection to Internet, nor does a connection to Internet necessarily mean Ethernet (it could be DSLAM direct or some AAL device).

?-)

OK. I thought you would be running new cable for the home automation devices, rather than connecting to an existing network. That's why I suggested using all 8 wires for your own purposes.

Matt Roberds

This one is really nice, only 39USD:

Cheers

Klaus