We recently had a 5.94KW solar PV system installed – twenty-two 270W panels (14 on the northish side of the house, 8 on the eastish side), with an ABB PVI-6000TL-OUTD inverter. Naturally I want to be able to monitor the system, but this model inverter doesn’t have an inbuilt web server (which, given the state of IoT devices, I’m actually kind of happy about); rather, it has an RS-485 serial interface. ABB sell addon data logger cards for several hundred dollars, but Rick from Affordable Solar Tasmania mentioned he had another client who was doing monitoring with a little Linux box and an RS-485 to USB adapter. As I had a Raspberry Pi 3 handy, I decided to do the same.
My wife and I have been making our own bacon since January this year. The year is almost over so it’s well past time I documented the process for posterity, especially since I expect my typing to remain legible for longer than my handwriting. Also, I know there’s at least a couple of people out there who are actually interested in this 😉
I’m posting this in the hope that it will be of benefit to others building their own books scanners. Here’s a bunch of of construction photos:
- Top piece of column slots onto bottom piece (lots of drilling and chiselling – see http://www.flickr.com/photos/tserong/7856430300/in/set-72157631235755228)
- An unbelievable amount of time was spent sanding and painting everything. If you’re going to do this, do it before assembling the base, or you’ll spend a lot of time with masking tape on the drawer slides :-/
- Camera mounts are both towards the back, rather than one towards the back and one towards the front. More visually balanced. They’re still basically centered though (one is on the near hole of the mounting bracket, one on the far hole, so they’re pretty much centered to within 1cm or so of each other).
The cameras are Canon A480s I picked up a year ago, specifically because they were known to work with CHDK. They’re both powered from cheap knockoff (i.e. non-Canon-branded) 3.15v mains adapters. I was going to splice those into the shutter release switch, but to my intense annoyance that’s not enough voltage for a trigger, so I’ve got a separate 4.5v 1amp wall wart wired into a push button and thence to two USB cables. It’s a bit less elegant than it could have been, but seems to work fine so far.
Total cost was something like AUD $300-400, with about half of that being the cameras. Note that if you’re in Australia, you probably won’t find keyboard drawer slides and column slides in large hardware stores (Bunnings/Mitre 10), so may instead have to visit a more specialist architectural fittings store for those pieces. I also couldn’t find wing bolts to mount the cameras, so substituted short 1/4″ bolts and packed them out with a nut each.
(This was originally posted in the DIY Book Scanner forum – I’m reposting here for posterity).