A look at a small solar panel set.

smackaay — Wed, 09 Mar 2011 01:49:05 +0000

A while back I had found a bunch of little solar cells on Ebay for cheap. I hadn’t really looked at them or tested them in any real way but today I wanted to see if they could power even a small project. As it turns out, I would require a great number of them in order to make even an LED light up (Assuming no capacitor or storage device). Since the sun was going down, I needed a constant source of light so I used my desk lamp. Here are the comparisons.

The individual solar cell

Those are the units I bought. I think I got like 30 for $10 or something. relatively cheap, but not really. I was expecting some decent performance, which I got, but not nearly as much as I expected.

This is the competitor. It’s the old Archer 6-12V solar cell pack. It’s quite old (25 years), the lens is dirty but it still works quite well.

The old Archer solar panel

And here is the test cell/array that I soldered together.

The solar cells soldered in a group of 4

Now, keep in mind that this was all done with a desk lamp. I maintained a certain distance from the bulb and only used the maximum measurement received by moving the panel around. Also given are comparitive measurements for the overall visible area exposed to light.

	Old Archer Panel	Cheapy EBay panel
Measured Voltage	5.245V	.162V
Measured Amperage	305 uA	628 uA
Calculated Watts	1.6 mW	.1 mW
Measured Area	14.05 Sq.in.	1.6524 Sq.in.
Cell Sizes	.788in x .563in	1.063in x .433in
mW per Sq.in.	.113mW per sq.in	.06 mW per sq.in

That all being said,you could still run quite a few little things at that low current rating if you were to link together all of the cells for whatever reason. unfortunately, nothing that I want to do could use them. So the lesson for the day is “Quality over Quantity”

Also, as an aside, here’s my new Agilent U1271A multimeter. Works like a dream!!!

My new Agilent u1271A, yay!

Perhaps tomorrow or someday I’ll give figures for sunlit voltages/amperages.

A Drawing of a Servo, for reference.

smackaay — Fri, 10 Apr 2009 07:29:56 +0000

Well, my servos have all come in for a project I’ve been working on. These ones being some cheap Chinese servos that I picked up off Ebay. Here’s a photo of one of them.

Chinese 9G RC Servo Photo

Now that I have them I guess I have no excuse in not doing the project, especially since I bought so many of them, despite them being cheap. In starting my project I’ve decided to offer a PDF of a drawing for the servo since I had no idea how big they were or what they would measure until they arrived, thus, if anyone else wants the drawing, they can use the dimensions for their own purposes.
Here are a couple of pics of the drawing for reference.

Chinese 9G RC Servo drawing

Chinese 9G RC Servo Solid

As the project progresses I’ll review the functionality of the servos. After I had ordered them I had read that they are susceptible to outside interference, especially from the likes of human contact around the housing. From what I read, this made the servo “Freak out”. We’ll see I guess, I’m going to make a standard testbed circuit for testing anyways.

So, anyways, for anyone who wants it the drawing, here’s the PDF

Chinese 9G RC Servo PDF

Hopefully someone will find it useful.

Steve's Junk » ebay

A look at a small solar panel set.

A Drawing of a Servo, for reference.