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election day 2015
Tuesday, November 3 2015
This morning I immediately began tinkering with my custom caller ID circuit. I soon discovered the source of the noise pollution on the phone line. I'd installed an audio transformer rotated 90 degrees from the way it should have been, meaning my downstream circuits had been connected directly to the phone line. It's hard for a transformer to isolate a circuit when one wire connects to one coil and another wire connects to the other one. Fortunately, nothing bad really could have happened even in that configuration due to the presence of capacitors and zener diodes. The real test of a circuit like that would have been a phone ring or a lightning storm, and neither of those had happened. In any case, it was easy to remedy, and once I did, I wrote a short script to test to see if the EM92547B would produce any caller ID information the next time we got a phone call. We seemed to be getting a large number of them in recent days, mostly urging us to vote for Democratic candidates in today's election. It was fortunate that I'd decided to use an Arduino Pro Micro as the controller for this circuit; it is the smallest & cheapest Arduino that comes stock with two hardware serial ports. One is the built-in USB support, though there is also an RX and a TX, which uses separate serial circuitry. I needed the RX for communication with the EM92547B, and I needed the USB to see what was happening. (I could have used SoftSerial to emulate a serial port, but it's always better to use actual serial hardware instead of attempting to emulate it.)
After more than an hour had passed and no phone call had come in, I realized this was no way to debug a circuit. Then I remembered that I have a Google Voice account that allows me to make unlimited domestic phone calls. (Here it is 2015, and I still don't have a cell plan of my own!)
Calls to my device produced a lot of noise data, but also a string of numbers. I did some research and confirmed that the caller ID serial data is expected to flow at 1200 baud, though it only uses seven bits per byte with one stop bit and no parity. With this configuration, I still wasn't getting any human-readable data. But then something else I found online tipped me off to the fact that the numbers I was seeing were a date in the form MMDDHHmm and that the "P" I saw soon thereafter referred to a "Private Caller" (which is how my seemingly-numberless Google Voice account was being labeled). So yes, my circuit was working, the only problem with it after all the hours of work I'd done beforehand being that rotated transformer. All I had to do now was write the necessary code and implement an answer & hangup relay.
The day had become so unseasonably warm that I could leave the front door and laboratory window open. I went down to the greenhouse briefly at some point and found the temperature was 102 degrees Fahrenheit.
After Gretchen came home from work and other things, we drove down to the Hurley town hall to vote. Most of the other people there didn't look like the sort of people who vote for democrats. As always, we voted straight "Working Families" party where possible, though for some reason Working Families was supporting the Republican in the race for Ulster County Legislature, so of course we voted for Doug Adams (who has successfully wooed us by knocking on our door, sending us liberal-friendly mailings, and carpeting the area with his signs). His primary opponent (Richard Parete) had evidently defected from the party after losing that primary. There was another race where only Republican and Conservative Party candidates were in the running, and for that one I wrote in Gretchen's name.
After that bit of democratic business was over, Gretchen and I parked the Prius in the field just south of Wynkoop about a third of the way to Hurley Mountain Road and took the dogs on a walk down a dusty farm road to the south. It was gorgeous evening, with luminous overcast, humid air, and light that seemed to make the fertilized cover crops to our east glow green. To our west, though, the vegetation was all dead, as if it had been hit by a neutron bomb. Beyond all that, there were still enough fall colors to make the Hurley Mountain escarpment into something of a lumpy purplish quilt. The evening was warm enough that I heard a lone surviving Katydid making its cha-cha-cha call at a speed proportional to the temperature.
For linking purposes this article's URL is:
http://asecular.com/blog.php?151103 feedback
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