[Robovergne] prides himself on the beautiful reef aquarium that he has set up in his home. These sorts of water displays require constant maintenance due to the mineral requirements of living coral. Rather than add mineral solutions manually, he decided to build a nano-doser using espresso machine pumps (Google Translation).

These vibration pumps run on mains voltage, so he had several options as far as how to control them. Using relays would likely make things pretty noisy, so he chose to use a zero crossing detection circuit to precisely control the pumps’ duty cycles and output.

His setup uses a PIC to control everything from the zero crossing circuit to the display LCD. An amount of product and the distribution time frame are entered using a handful of buttons mounted on the front of his control box, leaving the PIC to do the heavy lifting. It will calculate the proper length of time to run the pump based on several factors, including fluid viscosity and height of release.

It really is an impressive system, and while his needs are very precise, we imagine this sort of setup would be quite useful in building less complicated dispensers, such as those found in an automated bar.

Continue reading to see a few videos of his Nano-doser in action.

 

Filed under: chemistry hacks, home hacks

If you think that your water cooled rig is pretty sweet, check out this creation by Dutch PC enthusiast [Peter Brands] (Google Translation).

With his computer tweaked as far as he could imagine, he decided to spruce up his office a bit. In the process, he ended up tweaking his computer just a little bit more. After seeing a build put together by another computer enthusiast, he set off to construct a desk in which he could show off his computer. He spent some time drawing up plans with Google Sketchup and with the help of a friendly neighbor, started construction of his desk/PC case.

The desk is constructed from 3mm thick aluminum, and houses most of his computer’s components under a thick piece of glass. The only portion of the computer that is not enclosed in the desk is the 9-fan radiator he used for his water cooling setup. That part resides in his crawl space, which he connects to his PC via a pair of large water hoses he punched through his tile floor. If you are interested, you can see all 800+ pictures of the build here.

Simply awesome!

[Thanks duchie]

Filed under: home hacks, pcs hacks

Cats and dogs can get along quite nicely when they are raised up together. The problem with this type of arrangement tends to be keeping dogs out of the cat box and away from the cat food. [Ryan Meuth] tried out a simple electronic barrier to keep the dog away. It uses an IR transmitter and receiver to shine a beam of invisible light across the doorway to his cat room. In the demo after the break you’ll see that he took steps to make sure the cats don’t set off the alarm. The beam of light is set high enough that their bodies don’t get in the way, and the firmware measures the amount of time the beam was broken in order to avoid false positives caused by the cats’ tails. If the dog does try to get into the room it will break the beam and set off a high-pitched alarm sound.

It’s interesting that the dog doesn’t like the sound but the cat’s don’t seem to be scared of it. Also, we’ve got a less-than-ferocious feline that would love to chew on the cord that connects the two modules. Still, it’s a solution that works for [Ryan] and could be incorporated into an automatic feeder to keep the dog away from feedings while you’re out of the house.

This mechanized table automatically expands from seating for six to seating for twelve. We tried to capture the action with the three images above but don’t miss the transforming goodness in the video after the break. Alas, we’ll never see something like this in real life because it resides on a yacht worthy of Robin Leach’s attention. We wouldn’t have a problem copying the geometry of the tabletop pieces, but there’s got to be some serious design work to pull off the structure controlling the movement. No solid price is listed, but the creators note that construction costs are in the tens-of-thousands of British Pounds. We’ll stick to our Ikea furniture hacks for now.

[Thanks Luke]