Connecting groups of sensors across long distances to an UNO

Hi, I have a project wherein I have to connect groups of light, temperature, and sound sensors for data collection in clusters throughout a warehouse. Is there any device or special technique I can use to wire everything simply? Reducing clutter is pretty important as is cost.

I found an answer in another forum/thread. The solution for my problem looks like http://smartgreenhouse.org/index.php/products/robotics/catkit-long-distance-connectivity. Just a matter of hooking each sensor up to the 3 pins and plugging the whole thing together from what I've been reading. Does anyone know more about these CATkits?

I just assembled my first cat and kitten tonight and will try to find time this week to get them online to see how well it works. I intend to wire them up to some disused CAT5 in my house and some sensors.

I assumed it would talk SPI over pins 11-13 (plus one other for SS) with an Uno, but the example provided uses pins 0, 1 and 2 for an 'SPI LCD' device. So that kind of surprised me. Pin 13 is not even routed to any of the 3 RJ45 jacks. So that leaves one doing their SPI more slowly via software. I don't suppose that's problem in practice - for remote sensor and control links.

Pins 12 and 13 have been intentionally left as passthrough pins so other shields can have h/w SPI connectivity. Only Pins D0-D11 and A0-A5 are connected to the RJ45 for a total of 18 signals. If you are using an ethernet shield for example, D10 and D11 should remain unused by the sensor network.

As the previous poster mentioned, for virtually every other (lets call them low speed) SPI situations, the SPI LAT/DAT/CLK lines can use any other group of digital pins. For example we have a 4x20 LCD display using SPI on D2/D3/D4 over a 25ft CAT5 cable connected between the CATkit shield and the Kitten.

There is a "next generation" CATkit shield on the way for the MEGA and DUE board formats which specifically connects the h/w SPI ports (50-53) to an optional RJ45 connector for high speed SPI over CAT5.

:slight_smile: