I have a couple of projects in mind for my R-Pi which I thought I'd share. I'll likely combine them with some of my R-Pi hardware fixup ideas. Again, feedback welcome.
1. NTP Clock, mine will be based on the EM406A http://proto-pic.co.uk/20-channel-em-406a-sirf-iii-receiver-with-antenna/ primarily because I have a couple already, but the UP-501 may be a better choice http://proto-pic.co.uk/32-channel-up-501-gps-receiver/
Nothing particularly difficult here, the receiver has a PPS output which gives an accurate pulse at the start of every second. Wire this up to an available GPIO pin, and the serial tx/rx to the Pi onboard serial port and the rest is software.
I'll also include an RTC chip so that it can keep local time if the GPS network should ever go away.
I'm intending on trying to power the Pi + GPS from a TMLM04105 (177-2160) which is a tiny 4W 5v SMPS, again I have a few of these already. An ECL15US05 is an alternative if 4W isn't sufficient.
Something like this: https://picasaweb.google.com/selsinork/Prv?authkey=Gv1sRgCKjI3MiDpL7taQ#5765856610331714914 any needed level shifting being taken care of by using 74VHCxx gates which tolerate up to 7v inputs
2. A 4 channel remote mains power switch for some PCs. I already have an expensive APC AP7922 16 outlet network controllable PDU, but find it lacking in a couple of ways. It would be nice to be able to know when the PC is actually turned on, to be able to remotely push power and reset buttons, and to get access to a serial console.
So, Pi with a MCP23017 for 16 GPIO pins, four groups of four pins giving me four channels.
Of the four pins:
1. to switch a mains relay, allowing complete removal of power
2. reed relay connected in parallel with power button
3. reed relay connected in parallel with reset button
4. input connected to the PC's power LED - this lets me determine if the PC is powered on.
Next is two SC16IS762 (2101310) dual port SPI to UART chips to give me four serial ports that I can connect to the PC's to get access to serial console. I'll use some RFC2217 software to redirect these over the network.
The end idea with this one is to give me complete out-of-band control. I've had some experience of the onboard remote access chips, and lets say it's been less than wonderful - fine until you really need it! Even with expensive stuff like HP iLO or Dell DRAC you can still find yourself in a position where you need to be able to do a proper power cycle and then physically push a button. So I'm hoping this project will at least partially solve it for me.
It doesn't escape my attention that combined with an RTC something like this could be used to turn lights on/off at given times, heating control whatever... Also, I can connect many MCP23017 to the one Pi to expand the number of channels etc.
So, there's a couple of my ideas.. What are your ideas for your R-Pi projects ?