I recently blogged about some of the basic concepts behind BeakGeek, and said the next step was to prototype a solar powered wireless camera. Well, it's done. Or at least the first prototype is done. It's been working for five days now, but we are not yet satisfied with some of the design points. We will be working to refine the design over the next few months. For now here are some of the important notes:

**Design Goal: Assemble a simple solar powered wireless camera that is capable of streaming video as well as emailing a jpeg image on motion detection. And do it for under $500.

Network Camera

• Trendnet TV-IP110W

• Mini patch antenna (2.4GHz)

  Finding a network camera that draws as little power as possible and still gets the job done was bit of a challenge. Right now we are running a Trendnet TV-IP110W that's drawing 3 watts, but it falls short in a few other areas. Among the notables:

  First, the motion sensor requires Active X and thus Internet Explorer (this is a common requirement among cameras we have tested). And we are still trying to find a setting on the motion sensor that triggers when a bird visits the feeder while not triggering when a cloud passes overhead, casting the scene into shadow. This may be an unavoidable area of compromise with a camera at the $100 price level.

  Second, there is no way to schedule operation of the camera within the control panel - it's on all the time. One can schedule when the motion sensors operate but not the camera itself. We did test a Panasonic that had this feature, but it did not allow for an external antenna. Which brings us to the good parts - this camera does support an external antenna to extend the wireless range and the image quality is fine for this use case. We will continue to test different models of cameras until we can find the right price/performance mix.

  The camera was mounted inside of a Radio Shack project enclosure with some 3/4" PVC fittings to allow room out the back for connectors. We will be evaluating the official Trendnet branded outdoor camera enclosure to see if it's worth the extra price.

Power

• Two generic 5 Watt solar cells
• 12V deep cycle battery 55 Ah
• Solar charge controller

• 12V to 5V voltage regulator (similar model)

  We computed the power requirements assuming 4 watts of power draw (3 watts plus a watt for loss due to inefficiencies in the system), and figured it would need to run for ten hours per day. So 40 watt-hours per day total. The system is running on a rather large battery that we borrowed from another project that has a 55 amp-hour rating, so should supply about 660 watts-hours. That should last over 2 weeks under good conditions without even hooking up solar. However, since we are running the prototype camera 24 hrs per day we are actually running 96 watts hours per day, so our time is reduced. We are researching options to run a DC timer to control the load (camera), and/or a voltage controlled relay that would supply power to the load only when the solar cells are providing some level of voltage (like during daylight hours).

  Unfortunately, most options that we can find are solar charge controllers designed for solar lighting, and the voltage controlled relays/timers are set for dusk to dawn (or some variant), which is the opposite of what we need for the BeakGeek use case; we really need dawn to dusk. The good news is it's obviously doable, we just need to modify something to work for dawn to dusk. The other option is to spend a bit more for a camera that supports scheduled operation from within it's control panel. The problem with that solution is that we may want to attach another load to the system, like a camera enclosure with heater/blower, and would like to control all loads with one timer/relay. We will continue to work on this issue as it saves us over 100% in power draw per day, and we sure do not need to run the camera at night for this application.

  We are running two 5 watt solar panels in parallel to give us 10 watts max. In our area of Colorado it's pretty safe to expect an average of 5 hours of sun per day, so we are just getting by at 50 watt-hours per day of solar power. Please keep in mind that that is a very rough estimate. We could have used charts and weather data, but I think we are close enough to get the prototype running and build some empirical data. 15-20 watts worth of solar panels might be more realistic to cover more use cases. Yet another design point to refine.

  The two solar cells are running through a simple charge controller, which gives us the ability to add more solar cell power without worrying about overcharging the battery. The charge controller also helps to regulate the voltage and prevent under/over voltage/current conditions. The charge controller is technically not required at 10 watts or less, but we estimate the system would need to be installed someplace that enjoys favorable solar energy conditions - like the US SouthWest - to run reliably below 10 watts.

  The last piece of the power puzzle was to drop 12V DC to 5V DC in order to power the camera. We did this by cannibalizing a cigarette lighter adapter that is designed to power a GPS unit. It's rated output is 5V at 2.5 Amps max. You might be able to find one that is rated for 5V and 1 Amp that may work, but we decide to pay a little extra to get a bit more margin. And since I just smoked (literally) a similar "bargain" adapter that was only rated 800 mA, I would be very careful here - we do not want to start a fire!

  This all got hooked up with some 18 gauge wire, power plugs, and solder. We then stuffed the battery and electronics in a cheap plastic toolbox we picked up on clearance, and mounted a one sided feeder, camera and solar panels to a fence.

Summary

We still have some work to do to refine this design, but we are encouraged enough with the initial results to move on to the next revision. More to come.

Man who says it can not be done should not interrupt man doing it

--Chinese Proverb