Thursday, October 1, 2009

Priming for Microhydro

It's been more than a year since my first (and last) post. We're coming up to the final stages of approval or our micro hydro application. As far as we can tell the biggest hurdles are overcome - First Nations approval, Environmental Assessment done, Fisheries and Oceans okayed, and approval from the downstream license already on the creek we want to use.

There should be enough power to handle 4 household comfortably for 8 months of the year while the creek flows high during the non-summer months.

The environmental report leads directly to my next personal project. Even though we had planned on only running it 8 months of the year, the environmental report recommended leaving a minimum flow in the the creek.

Perfect opportunity to learn more about wireless RF transceivers and micro controller boards.

My plan is to develop a micro controller application that will remotely sense the water flow and automatically shut-off or redirect the intake for our micro hydro pipes.

To start with I ordered the XBEE XSC 900 MHz Development Kit which comes complete with two evaluation boards - one that plugs directly into the computer, and the other has a 'null modem' attachment so it's easily configured with the included X-CTU software to do a 'range test' of the two Xbee Modems.

According to published specs, these little modems (about 1" square) can transmit outdoors line-of-sight for more than a mile. The real question is can they do it in the real world - or at least in an outdoor environment filled with trees and bushy sloped areas?

Day 1: Called support line because I couldn't get the modem to be recognized by the software. Newbie error - receiver was not seated completely into board.

Day 2: Learning something new at this age is proving difficult.
Decided to test it on Nose Hill in Calgary,
a huge undeveloped area with many trees and open areas. Hooked it up to supplied 9V industrial alkaline battery, placed it in a wooden box, and again inside a plastic bag, only allowing the small (2") wire antenna to protrude. Took dogs for walk and placed it in a secluded very bushy area far from the parking lot. According to Google Earth it was around 1km away. This would be a real world test.

Proved to be more of a test in patience.

I returned that afternoon with my truck, laptop and the other modem, only to arrive at the first location to find out that the Modem Driver had disappeared. Apparently once I disconnected from my home network, it lost the COM5 port it was using at home. My attempt to reinstall the driver was met with a request for the original CD. back home I went.

After installing it again with the network detached I now had a COM6 to work with remotely.

However upon returning to the parking spot I did not detect any signal at all. Undeterred I proceeded to the next parking lot on the hill - this one about .8km away but perhaps on a better open area. Still no luck in getting even faint signal. One more try at the high Nose Hill Lookout lot resulted in the same failure to receive anything.

Finally I left the lot to walk up to the spot and bring back my remote modem closer to the truck - a spot only 300m away. Walking back to the truck to test again and it still showed no signal. When I brought it back to the truck, it was obvious it was a modem or battery problem as there was nothing showing up even when the box was next to the receiver.

Returning home for closer inspection revealed the power connection had been jarred loose - probably from the dog walk and my haphazard mounting inside the box.

Decided that I could do one more quick test around the neighborhood. Leaning the remote receiver up against the upper office window, I left with my laptop in the truck to see what kind of neighborhood reception there was. Garage out front was great - but lost all contact around the block, only getting sporadic signals as I returned around the circle on the way back to the house. GPS indicated it had to be 200m or less. That was disappointing to say least...

But once again I returned only to find that my mounting method had failed miserably as sometime during my 4 minute ride around the block the modem had fallen from its perch on the window sill to lay comfortably on the floor under the couch.

Well ... that did it...

Inspired by reading Make Magazine articles for the last month, I rebuilt the container using leftover parts (hard drive mounting bracket, broken cassette case, screws and electrical tape) - into a secure, easy to modify, test container...

Here's where it's at ... testing starts once again tomorrow...

The case is reused from a small smoked salmon container. Great native drawings on outside sliding top. Here I have the collected parts ready to go...

Using small screws to mounted both the board and the hard drive bracket for the battery, securely for the first time.

Final test ... Power Connected ... Lights On .. ready to go..

Slight modification to sliding lid, sawing a small gap to allow antenna to protrude and cassette case piece to lock lid.

Closed and ready to go.


  1. One of the pieces in my kit, which you may want to see if is available for your use, is a router. Mine is a plug-in, which wouldn't help, but the basic premise is that besides having its own sensor it is effectively extending the range of any XBee radios. So if there is one available for your kit (type and frequency) it would be able to extend the range.

  2. I'll check - thanks. When I talked to the tech guy I was under the impression there was little I could do with extending these radios. The Xbee Pro modules had a few more options and were much better at the point-to-multipoint transmission models - but, saying that, I understand that a router would basically just be a signal booster - so I don't know why it wouldn't be possible.

    Thanks for the suggestion


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