Archive for March, 2006
Another of my hobbies is keeping freshwater tropical fish. Ever since moving into my new house, and building my electronics lab upstairs, I haven’t been too interested in the fish. I give them more water when they need it, feed them on occassion, and do minimal basic maintainence.
The 55 gallon tank has gotten quite out of hand. A single variety of cryptocorne had gone on a killing spree, and had consumed the entire floor of the tank, wiping out every other plant that was in there. After it had consumed all there was to consume, fate turned the tides, and algae began to consume the crypts. So, with much disgust, I threw away all the crypts (mostly all covered with algae)… along with them went most of my substrate, entangled in the massively thick root balls of the crypts. So now my 55g sits empty – except for the fish, some huge snails, and the ugly life support equipment.
The tank normally has 108 watts of T5HO lighting (excessive for fw) , however, without any vegatative competition, algae would quickly rule the roost had I maintained normal lighting. So, I thought this would be a good application for LED lighting. The weak, sickly glow from “white” piranha leds will give me enough light to see my fish, and keep them accustomed to a day/night cycle, but not enough for algae to survive on.
My solution involves 24 white piranha leds, with a color temp somewhere around 5000 kelvin. The 24 leds are broke up into four strips of six, those four strips wired in parallel across the power supply. The power supply is a LM317T wired up as a constant current regulator.
The strips are designed with basic thermal management in mind. Since I am running the piranha at nearly 150mW, they generate a fair amount of heat. Therefore, I designed the strips with a maximum amount of copper possible, to act as heatsink and radiator.
All together, the ‘fixture’ consumes a little over 4 watts of energy. Here is the basic schematic of how things are wired up. This design is not very ‘safe’ … should an led strip fail as an open, the regulator will provide too much current to the remaining strips. The addition of a transistor and resistor to each strip would help combat this problem, by switching the current programming resistor in and out of the circuit… but this would require me to re-draw everything, make new PCBs, etc etc. This solution only needs to last a few months, once warmer weather arrives, I’ll be mail ordering some plants and have the tank restocked and the main lights working again.
Popularity: 22% [?]
The sidebar has been on quite a growing streak lately – first a bunch of new statistic driven links, and now many many new categories.
Since my post count is getting pretty big, I decided now would be a good time to organize it, rather than wait for it to get even larger. So I have gone back through every post, and further classified them into different categories.
It should make it easier to find things now, instead of it being all lumped under “Project”.
Popularity: 12% [?]
I have added some new plugins for wordpress that lets me get a better idea of which posts are popular and which have never been read at all.
Readers, you will notice on the sidebar, there is now a “Most Popular” section. It will list out the overall most popular when viewing the main page or viewing individual posts / pages. If you go into the monthly or category archives, it will list out the most popular posts for that month or category.
Each post also has a popularity readout at the end of the post… this is probably going away, once I find where that little bit of code was added.
I have also added a plugin that lets me track referrers, links, enter pages, exit pages, etc. I don’t think the readers can see any of the stats it produces. I may make a stats page for everyone once I get to understand these plugins a bit better.
For post popularity I am using Alex King’s Popularity Contest
For the general http stats I am using Anders Holte Nielsen’s Counterize
Popularity: 12% [?]