Bill’s Blog

Just sharing my thoughts (which are my own and not those of my employer)

Archive for the ‘solar’ tag

More efficient solar power

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Once I got the solar powered webcam working, I started thinking about how to make it more power efficient.  Looking at the specs of the inverter, I found it consumers 3W all the time.  That’s a lot of power wasted.  To make things more power efficient, I replaced the inverter with a circuit I built.  It is a highly efficient 12v to 5v switcher.  The picture below shows the near finished product.  It all fit in a box slightly smaller than the inverter.  Now that it is installed, the battery lasts about twice as long.

IMG_8281

Written by bill

September 30th, 2009 at 11:31 am

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How to build a Solar Powered Webcam

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About six months ago I got this crazy idea.  What if I put a webcam up on our hill?  There was no power up there, so I thought of the options.  I settled on the idea of building a solar powered webcam.  Having never done this before, I set out to learn about solar panels, batteries, and webcams.  I’ve tried to capture the important parts here so you can learn from what I’ve done and build your own solar powered webcam.

First, select the camera.  There are hundreds of webcams to choose from.  I was looking for an inexpensive camera that could be mounted outdoors and that was wireless.  I was not running any wires up to the hill.  I decided to skip the PTZ cameras (the ones with pan, tilt, and zoom) since I knew I’d be running on battery power.  I choose an indoor camera with a matching outdoor housing rather than the outdoor cameras.  The main factor was cost.  My Trendnet IP-TV110W was $74.46 on Amazon.  Outdoor cameras are much more expensive.  Trendnet also makes an outdoor housing with a mount designed for the camera.  The other thing to worry about with a solar powered setup is how much power the camera draws.  This one says it draws 6 watts max.

The next thing to consider was how much solar power I would need to power the camera.  I assumed six watts max meant 2.5-3 watts nominal, or 60-72 watts each day.  At 12 volts, that’s six amp hours each day.  Since solar panel installations run off of batteries, they end up being just as important as the panel.  You need a battery that will hold enough power to run the camera all day.  The panel needs to provide enough power to charge the batteries each day with the limited amount of sunlight available.  According to Solar Oregon, Portland gets about 4 hours of peak sun on average each day.  To test my assumptions about the power bring drawn from the camera, I bought a Kill a Watt meter and plugged the camera into it for a week.  The power consumption was so small that it never registered on the meter.  Armed with this info I decided on the 15 Watt Sunforce 50032 Solar Panel.  The panel shoudl generate about 60 watts of power each day to the battery.  I ended up buying a 33 Amp Hour battery from Batteries Plus locally.  While I could have used a smaller battery, I wanted the extra power available for those winter days when there isn’t much sun.

To connect the panel to the battery, you use a device called a charge controller.  One side connects to the panel.  The other side connects to the battery.  Basically, it keeps the panel from overcharging the battery.  I chose the Sunforce 7 Amp model.

Once I had chosen the camera, panel, and battery, the next step was putting it all together.  I started by mounting the panel on a pole at the top of the hill in my backyard.  I fretted quite a bit over how to mount it to the pole.  In the end I used three 12 inch 2x4s, a metal L bracket, and a 4×4 post.  The top and bottom 2x4s are bolted onto the panel through the mounting holes provided.  The middle 2×4 is attached to the metal L bracket and resting on the panel mounts.

Solar panels work best when mounted facing South at roughly 45 degrees.  To accomplish this, I bolted the L-bracket to the side of a 4×4.  The 4×4 was concreted into the ground for stability.

Once the panel was in place, I connected the charge controlled and batter.  To keep the charge controller dry, I mounted a small (6x6x4) plastic sealed box to the 4×4.  Wires go in and out of the box through a small hole drilled in the bottom.  I chose the size of the box so it was large enough to fit the chrage controller, an inverter, and the power adapter for the camera.  I could have also just built or bought something to convert the batteries 12 volts to the fix volts used by the camera.  In this case, the Charge Controller is connected to the battery.  This is how the battery is charged.  The inverter is also connected to the battery.  The inverter has a cigarette lighter style input on it, so I bought a cigarette lighter style jack at a local auto parts store.  I used heavy duty velcro to hold the charge controller and cigarette lighter adapter to the back of the case.

At this point, there is power to the inverter.  I first plugged in an LED nightlight to test it.  Instead of a webcam, I could power lights. a radio, or other small electronic devices.  A solar setup like this can be used in many situations.

Once I had power it was time to mount the camera.  When I say the camera, I actually mean the camera, the camera housing, the arrestor, and the external antenna.  That’s a lot of stuff!  The first thing I bought was the camera.  I tested it out to get it working as I wanted, then ordered the housing.  Once it got here, I realized I needed an external wifi antenna.  I choose the smallest outdoor antenna from this manufacturer.  It is still almost 2 feet tall!  The reason for an antenna is twofold.  First, the camera is in a metal box.  Its wifi reception is going to be hampered by this fact.  Second, the camera is a ways away from the wifi router, which is inside and at the other end of the house.  I tested the signal first by walking around on the hill with my ipod touch.  It worked fine and so does the camera.  The arrestor has two functions.  The first is to convert the cable from an SMA to N-type connector.  This connects the antenna to the camera.  The second and most important function is to protect the camera from a lightening strike.  Finally, I had to plug the camera into the inverter in the box mounted to the 4×4.  I had to cut the power adapter at both ends.  The DC plug doesn’t physically fit through the holes in the camera enclosure, so the manufacturer recommends cutting the wire.  I had to do the same at the other end.  This was both to lengthen the wire and to fit the wire through the hole in the bottom of the plastic box mounted to the pole.

The next result is a solar powered webcam that broadcasts live video 24×7.  The total cost for the project was $564.60.  This is less than many of the outdoor cameras I looked at.  It is also less than what it would cost to hire an electrician to run 110V to my hill.  I thoroughly enjoyed building this and am now thinking of all kinds of things I could power with my solar panel.

Written by bill

May 2nd, 2009 at 10:22 pm

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Solar Powered Webcam Project

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I’ve been thinking about a solar powered webcam project.  I’d like to put a webcam up on a hill where there is no power nearby.  When I looked into the project, it doesn’t seem that difficult.  I’d need a few things.

My thought is to have the solar panel mounted to the top of the pole, and the camera enclosure mounted to the same pole.  I’d put the battery and inverter in a waterproof enclosure mounted to a fence nearby.

What’s holding me up at the moment is how to mount the panel, what enclosure to use, and what battery to use.  Any input on this is appreciated.

Written by bill

February 12th, 2009 at 11:41 pm

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