[Today’s run: 7 miles, about 2 of that walking]
Ok, I’m going to get serious about one of my projects.
This is the project to have the emergency broadcast box pause the current reading and resume after the emergency thing is done.
Yes, this may mess up the schedule a bit if the emergency thing goes off a lot or if one single emergency broadcast is longer than normal. But I don’t think either of those things will happen very often. Short emergency broadcasts happen at least once a month.
One of the pieces I’m missing in my broadcast rack is a controller which can look for physical actions and do something about them. I’m going to start out by using a BeagleBone computer to do that. You may remember that my autonomous weather station project is using the BeagleBone. The thing is a $50 board which runs a flavor of linux. It has GPIO capability, which means I can watch for relay closures or read voltages.
My Sage emergency broadcast box has a connection on the back which has a relay closure when the unit interrupts the regular broadcast and sends it’s own stuff. The Sage is the next-to-last thing in the broadcast chain, right before the transmitter. The BB will watch that relay closure. When it grounds out, I can do something. In the end I want to send a message over the local area network to the Rivendell computer to pause the playout. But I’m going to start by just sending an email to myself whenever the Sage interrupts the broadcast. That will help me prove that it actually works because I should eventually get an email and I can go look at the online log in the Sage and see if they line up.
Ok, so first up is to get the BB configured for the GPIO relay closure. Next, and in parallel is to get the BB working for sending an email.
I found the PDF of the Sage manual and here is the information I need about where to hook the BB to the Sage. You’ll notice there are two physical connections for ENC RLY. I take this to mean that I run two wires to those two connections. When the Sage is “encoding”, sending an emergency alert over the air, the two wires will be shorted together. Otherwise they will disconnected from each other. So my next trick is to find some online references to the BeagleBoneBlack GPIO that tells me how to monitor for this condition.
