PDA

View Full Version : auto-adjusting solar panel project. your advice is needed!



kicknitinkc
03-09-2010, 02:14 AM
Hey everyone, I have a big group project for my mechanical engineering senior design class that we're starting to get into now. Our goal is to increase the efficiency of a solar panel by creating a control system that keeps the panel pointing at the sun. The motors we will probably use are 2 - 360 degree rotation servos. They seem to be the best choice for this application. One servo will control the angle of the panel while the other will rotate the panel's orientation with east and west. Should a motor control unit be used for this or will the stamp2 do the job b itself? Another part to this project is that the system must monitor the temperature of the panel and motors to prevent overheating. An I idea we came up with was to use 1 thermocouple for each motor and solar panel. The ambient temperature will be monitored with a digital thermometer chip. Is this a reasonable setup for temperature monitoring? When the panel gets hot, the panels performance deteriorates, so we must come up with a way to cool the panel back to normal temperatures or just avoid overheating altogether. One method we came up with is to turn the panel away from the sun until it cools. Another idea is to have a screen, similar to a baby car sunscreen, deploy and cover the panel to filter out a majority of the sun radiation. The third idea is to use a cooling system that utilizes a heat sink or water cooling. So to sum it up, I'm not sure what all the bs2 is capable of. Would all this be possible with one or two bs2s? The motor thermocouples will most likely be omitted after testing shows that they wont overheat. Do you have any advice about what components to choose or about anything about the project in general? We are only building a small scale version and don't have much more than $200 to put towards the project. Oh yeah, I forgot to say that photodiodes will be used for light detection. Thanks for your input! I will keep this thread updated as the project progresses.

Mike Green
03-09-2010, 03:11 AM
A couple of thoughts ...

1) Servos are a good idea. A Stamp can easily control two or three servos directly.

2) Rather than a thermocouple, how about using just a digital temperature sensor? Maxim has a variety of digital thermometers (like www.maxim-ic.com/quick_view2.cfm/qv_pk/3241 (http://www.maxim-ic.com/quick_view2.cfm/qv_pk/3241)) that are inexpensive and work over a -55C to +125C range, some to 150C. Most are addressable so you can attach several to one set of I/O pins. The BS2 can't do 1-Wire protocol (although the BS2p can), but it can do I2C using subroutines or SPI directly. Most of the temperature sensors are 1-Wire or I2C protocol. There's a Nuts and Volts Column (#85?) that discusses I2C with a BS2.

3) Most solar power systems just turn the collector away from the sun to reduce heating when necessary.

4) If you haven't gotten the Stamp yet, get a BS2p/pe/px since it has the built-in support for both 1-Wire and I2C protocols

kicknitinkc
03-09-2010, 03:33 AM
Thanks Mike. Man you are on top of it! Haha parallax should pay you for how much you help people on this forum. Well me and 2 other groupmates have bs2s but it sounds worth buying a bs2p for this project,especially because the school is allocating some cash for our project. I'm going to do some research on the digital temperature sensor now. Thanks again!

hover1
03-09-2010, 04:07 AM
An interesting read is an aticle in Nuts and Volts in the August 2009 issue, Solar Tracker. This design used the BS2p40 chip. Also in the issue, the begining of a 4 part article on Experiments with Alternative Energy; this featuring Solar Energy. The author of the latter article also runs a nice website http://www.learnonline.com/index.html.

Hope that helps,

Jim

kicknitinkc
03-10-2010, 01:31 AM
Man those are some great references! Thanks hover1