Randy P. posted:I just want to throw in a comment regarding shift registers. If you're planning to use shift registers for either input or output with an Arduino, I highly recommend Macetech's Centipede shield. They are more expensive than just buying a bunch of MCP23017's and hooking them up yourself, but they are ridiculously simple to use, with an included Arduino library, and support up to 128 I/O ports per Arduino (my project uses 7 Arduino Megas and 7 of these boards.) I don't use them as "shields" because I'm using Megas and need two on several of my Arduinos -- I just wire them up separately. I use them to control turnout relays (using the relay board previously mentioned, with 16 relays per board = control 8 turnouts per board), for monitoring isolated track occupancy (using time-delay-off relays), for illuminating control panel LEDs (including RGB LEDs,) and for monitoring control panel turnout pushbuttons. Here is the product page link:
http://macetech.com/store/inde...o&products_id=23
64 ports for $25. They also provide great tech support.
Randy
P.S. FYI, I am building an autonomously-controlled 15'x30' layout, with Arduinos monitoring occupancy, scheduling routes, throwing turnouts, and more -- and sending Legacy commands to all motive power via the Legacy serial interface. This project was inspired by Prof. Chaos's layout, and the YouTube videos he posted. My Arduinos communicate with each other via an RS485 bus. If anyone is interested in this, we can start a separate thread about it, and share ideas. I've learned a lot of things the hard way -- the RS485 bus was a nightmare to get working reliably, for example -- and it should have been trivial.
Thanks for sharing the shield Randy. I will look at it more later and probably maybe make mine own if I could. I plan on using the MCP23017 for block detection.
I'm working on several projects for my layout. The current one is using JMRI and Arduino CMRI library for turnouts, block detection, signals, and more. I also have Legacy control tied in. I would be interested in talking to you about your project. Specifically the topic at hand here. Block occupancy.
