Tuesday, November 24, 2009

First Power Graph

I got around to putting the data into RRDTool. I just updated the post with some better looking graphs. I used this guide for creating stacked, outlined area graphs.

Sunday, November 22, 2009

Back to Juggling Multiple Projects

Earlier this week, I started work on a new xPL app, currently called xPLSys. It monitors disk space, memory and cpu utilization and sends xPL messages containing the data. I'm not exactly sure how I want to package those messages as there really isn't a schema to hold the info I want to send - so either I make up my own schema or send multiple messages - one for each stat being watched. It's been running for a few days now but has been pushed aside for something else.

My Brultech ECM-1240 power monitor arrived Friday, and I started installing it that evening. I finished up most of the wiring Saturday morning and have been deciphering the serial protocol for real-time updates. I've been using our xPLSerial app to interface to it and code up the interactions with the built in scripting engine. I have to say, it's a very cool app and you should download it and donate ;). Despite being distracted by CAL's upset of Stanford (HOORAY), I figured out the serial protocol last night and have now been fine tuning my script. I've been thinking about rolling this into an app, but there is virtually no cpu utilization with the script running in xPLSerial.

I did make a change to xPLSerial to assist with debugging and that change will get pushed out eventually. I'm also considering removing the xPL from the name and calling it something else. It's really a serial port scripting engine with built in xPL functionality, but doesn't require xPL. In the meantime, I need to figure out what I'm going to do with the power data I'm getting every second.

Saturday, November 14, 2009

Solar Contract Signed & ECM-1240 Ordered

We signed the contract a couple days ago with Real Goods Solar (Regrid Power) for a 3.68kW system. Projected install date is late February and power on in March. Might as well have it come online when there's more sunlight.

I also ordered the ECM-1240 power monitor from Brultech. I decided to put current transformers on the lines from the solar array, but I will have to extend those via Cat-5. They should be able to go 100 feet, but it looks like it will be very, very close to 100 feet or possibly more. Hopefully, it will work. I've already opened up a hole in the wall next to the sub-panel, installed a mudring and drilled through the stud next to the subpanel so I can pass CT wires from the subpanel to the mudring. I also ran a couple Cat-5 wires through the wall behind the subpanel to a closet in the adjacent bedroom. I'll need those to connect to the Cat-5 drops in that room to extend the solar array's CTs and possibly get the ECM-1240 on the network via a Lantronix MSS-100. With luck, it'll get here before the Thanksgiving break so I'll have time to work on it.

Tuesday, November 10, 2009

Power Monitoring

As we get ready for the solar panel installation, I've been looking into power monitoring systems. I'm going with the Brultech ECM-1240. This is their 2nd generation energy monitor and has been very popular with the Cocoontech crowd so it has been well tested in the real world. Brultech Support has been very helpful responding to my emails with timely replies. I am looking at purchasing Package A, which comes with the monitor, 2 200A split core current transformers (CTs) and 5 MicroCTs. I'll also need 8 more MicroCTs and possibly a couple of the 80 amp MicroCTs (for our AC unit).

We have a main panel with the electric meter that services the AC unit and a sub-panel inside our house. Everything else is fed from the sub-panel, so that's where the ECM-1240 will be. It will be easier because I can shut off the main breaker to the sub-panel, whereas the main panel has no shut off. The less I muck around in there, the better. I will have to connect the CTs from the AC breakers to the ECM-1240 upstairs by the sub-panel. The CTs can be routed over Cat-5, I just need to figure out how to get the CT wires out from the main panel and into my garage, but that can wait until the solar guys do the install. Maybe their electrician can help me out.

As for the solar install, we've finally decided on an array size, an inverter & an installer, but I'm waiting for the data access to be finalized before signing the contract. I've chosen not to use the ECM-1240 to monitor the solar array as I am working with the solar installer on getting access to the inverter via an RS232 add on board. They've been very responsive so far and hopefully this item will be resolved soon.

Friday, November 6, 2009

BlueTrackerScript Released

I figure everybody is tired of reading about solar and wants me to get back to automation stuff. I'm releasing BlueTrackerScript, an app that I use at work to tell if I'm at my desk (this affects forwarding for Google Voice Automation). Of course, you'll need a bluetooth adapter for your PC, leaving bluetooth running on your cellphone, and you'll need to add some actions to the included sample script, blue.js.

Since I use this on my work PC, I want it to be able to communicate with my home server without any interaction necessary (setting up ssh tunnels, etc.). So I created two special URLs on my public webserver, one for detection and one for timeout. The script will fetch the appropriate URL using Wget. On the webserver, it watches the access log for access to those specific URLs from a specific IP address (my work IP), and passes a message to the automation server if it detects those URLs have been accessed. The automation server then adjusts Google Voice forwarding.

BlueTrackerScript is available here.

Thursday, November 5, 2009

Cleaning Solar Panels Uneccesary?

Yup, I'm still on my solar tangent. Getting close to deciding on a contractor, but not yet. I ran across this Google study on their solar installation. Their study shows that tilted panels, like virtually all residential rooftop mounted systems, don't need to be regularly washed. Rain does a good job of cleaning off the dust. This would discount SunRun's solar panel washing benefit. Panels that are installed horizontally do benefit greatly from a cleaning, however. To see more details on the Google study, check out their slides.