Pool/Hot Tub Monitoring and Data Collection

Pools and hot tubs, although enjoyable, require monitoring and maintenance to keep the water clean and clear. [bhuebner] didn’t like having to constantly testing his hot tub’s vitals using test strips and water test kits. In an effort to autonomously monitor his hot tub’s water, he came up with a project he’s calling SpaSitter that records and tracks water quality indicators.

spa sitter The hardware is based on a Nanode (think Arduino with on-board Ethernet). Three sensors are connected to the Nanode and placed in his hot tub’s water.  The sensors measure pH, ORP and Temperature. That data is then uploaded to xively.com where the data is not just stored, but tracked over time and displayed in graph-form. Checking the vitals on your phone can also get a bit tedious so [bhuebner] set up an email notification if one of the measured data streams go outside of a predetermined range. He still has to add chemicals manually and hopes to see some automation added to the next project revision.

[bhuebner] made his code available and also posted detailed instructions, including how to calibrate the sensors, for anyone wanting to do the same thing.

Hippie-Redneck Solar-Heated Swimming Pool Slash Hot Tub

In need of a jacuzzi to complete your backyard but just don’t have the cash? Need a swimming pool for the little ones but tired of the cheap plastic ones popping and leaking all over the place? Look no further than [inexplorata]’s self-explanatory “Hippie-Redneck Solar-Heated Kiddo Swimmin’ Pool And Hot Tub“.

The pool uses a six-foot-diameter metal stock tank, provided by a neighbor. After some liberal use of JB Weld, the tank functions as a makeshift pool on the cheap, but the magic doesn’t end there. [inexplorata] found a solar thermal water heater that someone was getting rid of and snagged it to heat up the water, which is almost a necessity for most parts of the Northern Hemisphere right now.

A sump pump in a bucket handles water circulation, and [inexplorata] points out that the single water heater is more than enough to keep the water nice and warm (“hot enough to poach a rhino” is the scientific term used on the project page) so if you’ve got the means, this might be a welcome addition to the backyard! The build was posted on Reddit, the users of which had some helpful suggestions for improving the pool if you want to tackle this yourself. If you don’t have a solar thermal water heater, you could always make one of those too.

Hackaday Links: December 22, 2013


[Korben] is using a picture frame as a Bluetooth speaker (translated). He hacked a Rock’R² for this project. It’s a device that has a vibrating element which can be used to make any hollow item into a speaker.

Entertain yourself over the holidays by mastering the Apollo Guidance Computer simulator. It’s a JavaScript version of the computer used in the modules of the Apollo moon missions.  [Thanks Gregory and Paul]

Here’s a little mirror attachment that lets you use your laptop as an overhead projector. [Ian] calls it the ClipDraw. Affix it to the webcam and use the keyboard as the drawing surface. Since it’s simply using the camera this works for both live presentations and video conferencing. What we can’t figure out is why the image doesn’t end up backward?

This guide will let you turn a Carambola board into an AirPlay speaker.

Those who suck at remembering the rules for a game of pool will enjoy this offering. It’s some add-on hardware that uses a color sensor to detect when a ball is pocketed. The Raspberry Pi based system automatically scores each game.

We spend waaaay too much time sitting at the computer. If we had a treadmill perhaps we’d try building [Kirk’s] treadmill desk attachment. It’s made out of PVC and uses some altered reduction fittings to make the height adjustable. It looks like you lose a little bit of space at the front of the belt, but if you’re just using it at a walking pace that shouldn’t matter too much.

You can have your own pair of smart tweezers for just a few clams. [Tyler] added copper tape to some anti-static tweezers. The copper pads have wires soldered to them which terminate on the other end with some alligator clips. Clip them to your multimeter and you’ve got your own e-tweezers.

AquaTop: a gaming touch display that looks like demon possessed water

AquaTop_touch_displayAre you ready to make a utility sink sized pool of water the location of your next living room game console? This demonstration is appealing, but maybe not ready for widespread adoption. AquaTop is an interactive display that combines water, a projector, and a depth camera.

The water has bath salts added to it which turn it a milky white. This does double duty, making it a reasonably reflective surface for the projector, and hiding your hands when below the surface. The video below shows several different games being played. But the most compelling demonstration involves individual finger tracking when your digits break the surface of the water (show on the right above).

There is also a novel feedback system. The researchers hacked some speakers so they could be submerged in the tank, adding a large speaker with LEDs on it in the same manner. When fed a 50 Hz signal they make the surface of the pool dance.

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Build a waterproof music controller on the cheap


[Aaron] wrote in to show off the waterproof music controller (translated) he just finished building. He uses it in the shower — which makes us wonder how long he’s spending in there. We could also see it being useful by the pool, on the beach, or anywhere else that you need a cheap and easy control system.

His computer plays tunes while he’s getting ready for the day. This means he was able to use an inexpensive wireless keyboard for control. The donor keyboard has dedicated music control keys which he carefully traced to the PCB before removing the flexible sheets that detect key presses. Next he found a water tight food container and sized his protoboard to fit. You can see his button layout above. Holes were cut in the lid of the container, with a plastic membrane glued on the underside. This will keep the water out while still allowing him to actuate the momentary push switches.

Most mobile devices will work with wireless keyboards. If your car is nearby just hook your phone to the stereo and control it with this rather than building a dedicated beach stereo system.

Computer tracking of billiard balls

The folks at the London-based startup GoCardless have a pool table at their office. Being the techies they are, they decided to build a system that automatically scores games. The results, while not fully complete, are still pretty impressive for something whipped up during a 48 hour hackathon.

The automated score keeper uses a webcam duct taped to the ceiling right above the center of the pool table, The balls – red and yellow balls replace the rainbow of solids and stripes to make things easier – are found using OpenCV.

This build isn’t quite finished yet. The people at GoCardless are looking to improve the accuracy of their setup by using a camera with a higher frame rate and possibly moving on to physics simulation to predict where the balls should be. If these guys get the time, they could add something like augmented reality pool table to improve shot accuracy.

Vidia after the break.

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Skateboard tagging

We abhor vandalism, but we love art. Here’s a skateboard hack that lets skate punks young and old tag their turf while they ride. [D*Face], a multimedia street artist who grew up in London, added a mounting system to the bottom of his skateboard which includes a can of spray paint. We’re a bit surprised that there’s room enough for that, but the system fits nicely. They’re not locked into a constant stream because the system lets the rider (or a bystander) actuate the spray can via remote control.

But the brush is only one part of the painter’s tool chain. To get the most interesting effect, a pool was painted white to serve as canvas and a troupe of skaters was unleashed on it to try out the modified boards. Check out the video after the break to see the colorful and pleasing curves that result. We just hope nobody bailed and smeared the canvas at the same time.

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