A Raspberry Pi Has This Pool Covered

December 2, 2018 by 25 Comments

Far from being a tiled hole in the ground with a bit of water in it, a modern swimming pool boasts a complex array of subsystems designed to ensure your morning dip is as perfect as that you’d find on the sun-kissed beaches of your dream tropical isle. And as you might expect with such complex pieces of equipment in a domestic setting, they grow old, go wrong, and are expensive to fix.

[DrewBeer]’s pool had just such a problem. A decades-oldwired controller had failed, so rather than stump up a fortune for a refit, he created his own pool controller which exists under the watchful eye of a Raspberry Pi. The breadth of functionality is apparent from his write-up. In addition to the pump and heater you’d expect, he as a salt water system, environmental monitoring, and even an RTL-SDR to pull in readings from an RF floating temperature probe. It’s all exposed via a node.js API, and thus far has been running for over 6 months without mishap.

From where this is being written in the gloom of a damp November in a Northern Hemisphere maritime climate we can only envy [Drew] his pool and imagine it as perpetually deep blue and sparkling, invitingly cool against the heat of a summer’s day. If you have similar pool automation woes. perhaps you’d also like to look at this ESP8266 pool monitor, or another automation project using a Raspberry Pi.

FPV Antenna Leans Into The Bank

December 2, 2018 by 23 Comments

If you’re doing remote controlled flight, odds are you’re also flying FPV. Or you at least have a camera on board. If you’re transmitting to the ground, you may have noticed the antenna on your plane has some weird radiation patterns; bank your plane to the left or right, and your signal gets worse. [Ant0003] over on Thingiverse has a great solution to this problem that’s small, lightweight, and will fit into just about any airframe.

[Ant]’s flying a Mini Talon with FPV, and since planes turn slower than drones, and can fly much further than multicopters, the radiation pattern of the antenna is very important. In this case, [Ant] wants to keep the antenna perpendicular to the ground. This problem was solved with a cheap 9-gram servo and a few 3D printed parts that hold an SMA connector. One end of this wire goes to the video transmitter, and the antenna is screwed into the other end.

A servo alone does not make the antenna point straight up. To do this, [Ant] needed to program his flight controller. He’s using iNav, and a few clicks of the mouse makes one servo channel do whatever the gyroscope isn’t doing. The results (video below) speak for themselves. It’s an antenna that always points straight up, which is exactly what this video transmitter needed.

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Spring-Loaded Bed For K40 Laser Acts As An Auto-Focus

December 2, 2018 by 12 Comments

Laser engraving and cutting has something in common with focusing the sun’s rays with a magnifying glass: good focus is critical to results. If materials of varying thicknesses are used, focus needs to be re-set every time the material changes, and manual focusing quickly becomes a chore. [Scorch Works] has a clever solution to avoid constant re-focusing that doesn’t involve sensors or motors of any sort. The result is a self-adjusting bed that compensates for material height changes, ensuring that the top surface of the material is always a fixed distance from the laser’s head.

The way [Scorch Works] has done this is to make two spring-loaded clamps from angle aluminum and a few pieces of hardware. When a sheet of material is placed into the machine, the edges get tucked underneath the aluminum “lips” while being pushed upward from beneath. By fixing the height of the top layer of angle aluminum, any sheet stock always ends up the same distance from the laser head regardless of the material’s thickness.

[Scorch Works] shows the assembly in action in the video embedded below, along with a few different ways to accommodate different materials and special cases, so be sure to check it out.

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Wheel Of Fortune Gets Infinite Puzzles On NES

December 2, 2018 by 20 Comments

Wheel of Fortune is a television game show, born in the distant year of 1975. Like many popular television properties of the era, it spawned a series of videogames on various platforms. Like many a hacker, [Chris] had been loading up the retro NES title on his Raspberry Pi when he realized that, due to the limitations of the cartridge format, he was playing the same puzzles over and over again. There was nothing for it, but to load a hex editor and get to work.

[Chris’s] initial investigation involved loading up the ROM in a hex editor and simply searching for ASCII strings of common puzzles in the game. Initial results were positive, turning up several scraps of plaintext. Eventually, it became apparent that the puzzles were stored in ASCII, but with certain most-significant-bits changed in order to mark the line breaks and ends of puzzles. [Chris] termed the format wheelscii, and developed an encoder that could turn new puzzles into the same format.

After some preliminary experimentation involving corrupting the puzzles and testing various edge cases, [Chris] decided to implement a complete fix. Puzzles were sourced from the Wheel of Fortune Puzzle Compendium, which should have plenty of fresh content for all but the most addicted viewers. A script was then created that would stuff 1000 fresh puzzles into the ROM at load time to minimize the chances of seeing duplicate puzzles.

ROM hacks are always fun, and this is a particularly good example of how simple tools can be used to make entertaining modifications to 30-year-old software. For another take, check out this hack that lets the Mario Bros. play together.

CNC Machine Most Satisfyingly Mills Double-Sided PCBs

December 2, 2018 by 50 Comments

We know that by this point in the development of CNC technology, nothing should amaze us. We’ve seen CNC machines perform feats of precision that shouldn’t be possible, whether it be milling a complex jet engine turbine blade or just squirting out hot plastic. But you’ve just got to watch this PCB milling CNC machine go through its paces!

The machine is from an outfit called WEGSTR, based in the Czech Republic. While it appears to be optimized for PCB milling and drilling, the company also shows it milling metals, wood, plastic, and even glass. The first video below shows the machine milling 0.1 mm traces in FR4; the scale of the operation only becomes apparent when a gigantic toothbrush enters the frame to clear away a little swarf. As if that weren’t enough, the machine then cuts traces on the other side of the board; vias created by filling drilled holes with copper rivets and peening them over with a mandrel and a few light hammer taps connect the two sides.

Prefer your boards with solder resist and silkscreening? Not a problem, at least judging by the second video, which shows a finished board getting coated with UV-cure resist and then having the machine mill away just the resist on the solder pads. We’re not sure how they deal with variations in board thickness or warping, but they sure have it dialed in. Regardless of how they optimized the process, it’s a pleasure to watch.

At about $2,600, these are not cheap machines, but they may make sense for someone needing high-quality boards with rapid turnaround. And who’s to say a DIY machine couldn’t do as good a job? We’ve seen plenty of them before, and covered the pros and cons of etching versus milling too.

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3D Printed Brushed Motor Is Easy To Visualize

December 1, 2018 by 5 Comments

A motor — or a generator — requires some normal magnets and some electromagnets. The usual arrangement is to have a brushed commutator that both powers the electromagnets and switches their polarity as the motor spins. Permanent magnets don’t rotate and attract or repel the electromagnets as they swing by. That can be a little hard to visualize, but if you 3D Print [Miller’s Planet’s] working model — or just watch the video below — you can see how it all works.

We imagine the hardest part of this is winding the large electromagnets. Getting the axle — a nail — centered is hard too, but from the video, it looks like it isn’t that critical. There was a problem with the link to the 3D model files, but it looks like this one works.

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Connect Your Electric Heater To The Internet (Easily And Cheaply)!

December 1, 2018 by 18 Comments

Winter has arrived, and by now most households should have moved on from incandescent bulbs, so we can’t heat ourselves that way. Avoiding the chill led [edent] to invest in an electric blanket. This isn’t any ordinary electric blanket — no, this is one connected to the Internet, powered by Alexa.

This is a project for [edent] and his wife, which complicates matters slightly due to the need for dual heating zones. Yes, dual-zone electric heating blankets exist (as do two electric blankets and sewing machines), but the real problem was finding a blanket that turned on when it was plugged in. Who would have thought a simple resistive heating element could be so complicated?

For the Internet-facing side of this project, [edent] is using a Meross smart plug and a Sonoff S20 smart plug. These are set up through to work with Alexa and configured as an ‘electric blanket’ group. Simply saying, “Alexa, switch on the electric blanket” turns on the bed.

There are a few problems in need of future improvement. Alexa doesn’t recognize voices, so saying ‘Turn on my side of the bed’ doesn’t work. The blanket also shuts off after an hour, but the plug sockets stay live. There’s also the possibility that hackers could break into this Alexa and burn down the house, but this is a device on the Internet; that sort of stuff virtually never happens.

You can check out the demo of the electric bed below.

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