"Off Grid" DC Solar Electric Garage Lighting... Hard Wired and Fully Integrated

Instructables was kind enough to send me this neat little solar kit as a prize for being runner up in last year's "Off the Grid Contest".

The kit comes with a solar panel, an intelligent battery pack, a universal USB cell phone battery charger,  a wall adapter charger and a 12 volt LED light bulb with power cord.

The battery pack can be charged from either the solar panel or the wall charger from a set of terminals in the back. It has a built in charge controller as well as an alarm that will notify you of an error. On the front of the unit are two 12 volt "cigarette lighter" outlets and two 5 volt USB ports that you can use to draw power. On the front there is also a battery level indicator as well as a charge status indicator.

In these photos you can see the solar panel on a little wooden frame that I built for it. When I first got it I planned on using it for camping trips and emergencies so I made up this portable stand. Now I will make up an aluminum mount and mount it on the roof of my garage with the power cable routed through the roof deck, attic and over to the battery pack. For now I put the panel on the ground beside the shed whenever it's sunny.

The light bulb that came with the kit was particularly interesting. Even though its a 12VDC bulb it has an E26 screw base similar to the ones found on your conventional household 120VAC bulbs. The cord that was included had a bulb screw socket on one end and a "cigarette lighter" style plug on the other end to plug into the battery pack. As strange as the light bulb was it meant that I could install it in a conventional household light fixture as long as it was wired up for 12VDC and not 120VAC. I found more of the same bulbs on eBay and then gathered up some electrical boxes, 18/2 Romex wire, tools and got going.      

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Solar Tracker in the Internet Cloud

The major system components identified in the block diagram:
90 Watt solar Panel Two axis motion platform constructed from 2x4’s complete with wooden peg gears and re-used curtain rod/pole. Custom electronics – Electric Imp connected to stepper drivers, IO Expander and 6 Axis MEMS accelerometer/magnetometer Rechargeable battery – retired unit from my motorcycle as it is no longer capable of turning the engine over. Solar Charge Controller – cheap unit from ebay to make sure the battery doesn’t overcharge. Smartphone or web browser – monitoring status and remote control. This is a non-essential part of the system done purely for a learning experience to see what it takes to connect a phone to a remote device. (gotta remember to hide the URL so that I don’t have too many people trying to control the panel!) The tracker circuit includes a tilt compensated compass - the math was coded from an application note. The chip has 3 axis magnetic output and 3 axis accelerometer output. The magnetic output tells the system the azimuth angle and the accelerometer tells the system the the inclination with respect to gravity. The GPS location is hardcoded in the firmware (future will have this set by smartphone via the web). The firmware determines based on the time of day and geographic co-ordinates what the sun angle is with a Sun Angle algorithm ported to the Electric Imp Squirrel language from C++ (discussed in later steps). Firmware drives the azimuth and elevation motors to the Sun Angles based on feedback from the mag/accel. 

This whole thing could be done a lot more simply, but I saw a personal learning opportunity with contemporary web development techniques and was intrigued by the Internet Of Things made possible by the Electric Imp. Rather than just randomly reading web articles to get a superficial understanding, I immersed myself in the technology to come up with an most likely an overkill solution to a common problem. Most solutions on the market today are "light followers". They control motors in response to the intensity of light to maximize incident sunlight on the panel. These work well, are low cost and are really all you need. But, you will not learned any of the following on the electronics/firmware/web development side:

1. ASP.NET programming model for web based applications. This is the server side code that the smartphone connects to, to see the status of the system, or to drive inputs to the controller for manual control of azimuth and elevation for debugging purposes.

2. AJAX which allows a web page to update without server page reload. Allows a web page to dynamically query server data directly and update the regions of the page without page reload. This is how the monitoring data is updated.

3. SQL Server work on the back end. The data from the Electric Imp is logged in a SQL Server database. There was a time when writing SQL queries was second nature.... not so much anymore!

4. JQUERY Mobile - great open source library that simplifies working with the Web page Document Object Model. Just scratching the surface of it but it has taken the web by storm. It is a great way to develop Smartphone HTML5 "apps".

5. HTML5 capabilities and the relation to potential hardware independent phone apps. Bumped into a number of apps that will take the Web app and turn it into a traditional phone store application. Some are free until you reach 10000 downloads... yeah right!

6. The Internet Of Things model and what companies like Electric Imp and COSM are doing to make this a reality even for low budget hackers like me.

7. Appreciation of cloud based services and the power of having services provided by the cloud. The electric imp is fully cloud
based....  your firmware lives in the cloud and is downloaded when your device connects to the internet.

8. Algorithms for tilt compensating a compass.. Ultimately I implemented an app note but it was a major journey of "discovery" for
me.

9. Algorithms for sun angle prediction. Ported an Open Source implementation to the Electric Imp. Had no idea that this was such a complex problem. I don't fully understand the algorithm but tip my hat to anyone who does! IJW!

10. I2C hardware communication and associated peripherals - as long as I have been messing with electronics, never controlled an I2C peripheral before.

I'm sure I learned plenty more but I capped the list at 10!

I think the easiest way to tackle this documentation is to walk you through the building of the tracking base, then the electronics/firmware and finally the web app. The electronics and motion platform are independent components of the system. The tracker electronic module was designed to be a reusable component. The tracker base was designed to demonstrate peg gears and levers in another shameless attempt at stimulating my kids’ minds with engineering. A future weatherproof design using more 21st century motion mechanism is in the design phase and will be built over the course of the next year or so. I would like to offer that as complete package to interested consumers. 

OK, let's get started. 

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Making a 1 Watt Solar Array.

I love my neighbor’s garbage I call them the parts department. In this, instructible I am building a Solar Array out of 30 solar lights my neighbor threw out.

For this project I am only going to use 18 of the solar cells for the array I am building. The array will be able to charge a 12 volt 10 watt hour battery in a day. The total cost of building this array is about 5 dollars, a comparable array or solar cell can run you 60 dollars.

Since all the parts are salvaged, I will test every thing every step of the way, I don't want to completely assemble the array only to find out one of the components I used is faulty.

For testing you will need a multimeter.

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Create Your Own Solar Powered Mason Jar Nightlight from Junk

It's spring which of course means two things:
- Rain, snow and snow-shovels have left wornout, damaged and broken solar garden lights in the yard.
- Garden centers are running specials on new solar lights (I found several stores selling them for $1 each)

I managed to avoid throwing out several broken solar lights by using them to create some neat "Mason jar nightlights"...just charge them up during the day and they light the way at night.
I liked the results and noticed pre-made "Solar Mason Jars" are selling for $24.00 on Amazon and even "Solar Lid Lights" (just the lids) are $12. So I tried a few more variations with a few of the $1 solar lights and put together this Instructable so we can make our own!

This Instructable describes how to create either style of Solar Mason Jar Nightlight (from salvaged or new solar lights)  
We'll start with the "new light" variation, it's a pretty easy project!

What's Needed for this Instructable:
Solar Garden Lights - either salvaged or new - you know the type, typically a cylinder on a stick with the solar panel on top Mason Jar, Band and Lid  - I used small Half Pint (8oz) Kerr brand decorative jelly jars, but any canning jar will work. Frosted Glass spray paint - I used Rust-Oleum brand. NiCad batteries - the damaged lights generally have rusty worn-out batteries, typically AA. Even new budget lights occasionally need new batteries. (found these at Harbor Freight store). If you have a charger you can try re-freshening old batteries with that. Something to cut with - I used a Dremmel, X-Acto, Tin snips and even a bench-grinder depending on how well a particular light fit into the jar.  Glue or Hot Glue gun Screwdriver - often required to access dead batteries Optional: Soldering Iron and Solder - damaged lights will likely need some repair, however new lights shouldn't require soldering Vice or clamps Colored Spray Paint - I had some sparkly blue auto paint around so added a light coat of blue to a few,
I like the blue color a lot!  Just go light on the paint, I made one that is really just too dark.
Let's make some!Bargain solar lights are either:
- larger than the 2.25" opening of the Mason jar
- smaller than the opening in the Mason Jar

Larger: The first style I tried was (on clearance from 4th of July) just a touch larger than the opening. Easy enough to detach the blue top section from it's plastic post (not shown here).  Next to make things fit I simply had to cut the sides of the light off using the dremmel and a tin snips.
This particular size light worked really well because no rewiring, cutting of the lid or even gluing of the lid was needed. I found these at Menards for $1 ...think I better go back for some more!

Smaller - Here because the solar panel itself is so small it would slip through the jar "band". I had to cut a hole in the lid, and then glue the light to the lid.
(another solution might be to copy the size of the lid out of something easier to cut, plastic (like the top of a Skippy jar maybe) or wood. I haven't tried this technique yet)

I cut the lid hole 2 different ways:
- Marked a square on the lid and used the Dremmel to cut the opening.
- I also used a hole-saw to create a round hole. The hole-saw technique is easier, but partially blocks the solar panel.

Another problem with the smaller size light: the battery inside was a 1/2 AA...looked like a AA only half the length. I couldn't find a replacement so I made my own battery holder from spare cardboard and used the AA size...see the images below.

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Solar Plane

Introduction: 
This instructable will show you how to create a solar powered plane. This project was done at Newman Smith HS in Carrollton, Texas and was sponsored by the Texas A&M Aerospace Engineering Department. We received most of the needed parts from Texas A&M and built the plane for the High School Solar Plane Competition on May 25, 2013. The project is not for the beginner as it gets a bit complicated. Skills that you will need include soldering skills, plane building skills, monokoting skills, and general R/C plane knowledge. Our team ended up with the Most Creative award and 2nd place in Endurance. 

Special Thanks to Texas A&M, NSHS Teachers & the DIY Drones Community (http://diydrones.com/forum/topics/solar-powered-plane).

Below are some pictures of the completed project. The next step will be the list of materials needed. 
Also included below is the link for build basics and aircraft aerodynamics- there are two PowerPoints included by Texas A&M.  If you are going to do the project, printing out these two PowerPoints will help you immensely. However, please take note that all the cells must be in series, not in parallel as one of the PowerPoint presentations describes. 
https://drive.google.com/folderview?id=0B_bYmGJ0v1Ncb283TF8tWXF6ZWc&usp=sharing

Want to see more photos? PM me and I'll give you a link. 

Materials Needed: 
Glider (we used the Gentle Lady) 
Monokote (We ended up using about 3 rolls- two for the 8 foot wing [bottom] & body of the plane and another clear roll for the panels)
3x6 Solar Panels
Tabbing Wire
Bus Wire
Normal Wire
Micro Servos 
Push Rods 
Nylon Control Horns 
Propeller 
Li-Po Battery
ESC (Electronic Speed Controller) 
Charger 
Connectors (for Wires) 
Receiver 
Propeller 
Electric Motor 
CA Glue 
Heat Shrink Tubing 
Sewing String 
Pairing Connector (depends on your transmitter/receiver) 
Nuts (for balancing wing) 
Balsa Wood Sheets (optional- depends on how big your wing is) 

Tools: 
Soldering Iron
Flux
Solder 
Hobby Knife and extra blades 
Heat Gun 
Sealing Iron 
Large Table 
Sand Paper 
Drill
Wire Cutter 
Digital Multi-Meter
First Aid Kit 

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