LEGO® My Single-Phase Induction Motor

[Diato556] made a really cool single-phase induction motor with parts mounted on Duplo blocks. He has posted an Instructable where he uses these modular parts to  demonstrate the motor and the principles of induction as described after the jump.


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Energy-Saving Fireplace Thermostat

[Andrian] has a boiler stove that heats water and sends it to a radiator. As the fireplace heats the water in a boiler a temperature sensor opens the a valve to send the warm water to the radiator. The radiator sends its cool water back to the boiler to be reheated. The valve is slow, so before the boiler can send all the water to the radiator, it’s getting cool water back causing the valve to close while the heat is built back up. To prevent the valve from working so hard and wasting energy, [Andrian] designed a better thermostat to control the valve operation.

The thermostat uses one LM85 temperature sensor to check the water in the boiler and another one for the ambient temperature. Once the boiler water reaches the desired temperature, the valve is opened via relay. The system waits for half an hour and then checks the boiler temperature again. The brains of this operation is an ATMega168 with a 32.768kHz crystal as the RTC. Code and PCB files are available in his repo.

We love to see these types of hacks that challenge the status quo and increase the efficiency of appliances. We applaud you, [Andrian], for turning your dissatisfaction into a positive plan of action and for sharing your experience with the rest of us!

If you want to up the eco-friendliness of heating water a bit, you could heat the water with a compost heap.

An Etch-A-Sketch to Fetch the Time

For someone who has never used stepper motors, real-time clocks, or built anything from scratch, [Dodgey99] has done a great job of bending them to his will while building his Etch-A-Sketch clock.

He used two 5V stepper motors with ULN2003 drivers. These motors are mounted on the back and rotate the knobs via pulleys. They are kind of slow; it takes about 2 1/2 minutes to draw the time, but the point of the hack is to watch the Etch-A-Sketch. [Dodgey99] is working to replace these steppers with Nema 17 motors which are much faster. [Dodgey99] used an EasyDriver for Arduino to drive them. He’s got an Arduino chip kit in this clock to save on the BOM, but you could use a regular Arduino. He left out the 5V regulator because the EasyDriver has one.

[Dodgey99] has published three sketches for the clock: one to set up the RTC so that the correct time is displayed once the Etch-A-Sketch is finished, some code to test the hardware and sample the look of the digits, and the main code to replace the test code.

The icing on this timekeeping cake is the acrylic base and mounting he’s fashioned. During his mounting trials, he learned a valuable lesson about drilling holes into an Etch-A-Sketch. You can’t shake an Etch-A-Sketch programmatically, so he rotates it with a Nema 17. Check it out after the jump.

If you’re paying attention, you’ll realize we just saw the exact opposite of this project a few hours ago: a CNC tool (laser cutter) controlled by turning Etch-A-Sketch knobs.

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Now You’re Washing with Gas

[Michiel] likes to wash his clothes in warm water. Like a lot of machines, his draws from the cold water line and  heats it electrically. Gas is much cheaper than electricity in the Netherlands, so he wanted to be able to heat the water with gas instead. Hot-fill machines already exist, but few models are available and they’re all too expensive.  [Michiel] rolled up his sleeves and hacked his brand new washer into a hot-fill machine.

He started out thinking that he’d just connect the hot water line instead, but that proved to be too hot. He found out it needs to be about 35°C (95°F), so he decided to mix input from the hot and cold lines. Since it’s a shiny new machine, [Michiel] wanted an externally mounted system to keep from voiding  the warranty. He got two solenoid valves from the electronic bay and used a PIC16F to make them dance. He wired up a light switch on a two-panel face and used the blank plate for power and status LEDs.

[Michiel]‘s design works like a charm. The machine used to draw 2000W to heat the water, and peak usage now is as low as 200W. He noticed that the washer drew a lot of power in standby mode so he added a solid state relay and a bit more code. Now the electricity to the machine is cut after two hours and [Michiel] saves about €97 per year.

Crafternoon: Forget Potatoes, We’re Making Stamps with Lasers

No, that’s not Heisenberg without his hat. It’s [Jens], and he laser-cut a stamp of his face out of EVA foam. He made the laser cutter himself, which we covered a couple of months ago.

Let’s take a brief interlude to discuss your beautiful eyeballs. Keep them safe, okay? If you’re going to play with lasers, be smart and protect yourself according to the wattage and wavelength. Alright, back to business.

[Jens] started by making a stencil from a photo using this tutorial. He added a frame and supports around his face to keep everything where it should be. [Jens] then turned to Inkscape to generate the g-code using the laser plugin and then proceeded to cut his countenance into EVA foam.

After gluing the foam to a wood backing, he cut off the supports. Now it’s ready to stamp. You could use a brayer if you have one or maybe your wife’s rolling pin to apply whatever ink or paint you want to use. [Jens] loaded up his stamp with a sponge.

Don’t Just Go Sticking That Anywhere: Protect the Precious With a USB Wrapper

Oooh, look, a public charging station. Should you trust it? You might get juice jacked. Oh wait, you’ve got a USB Wrapper designed by [Scasagrande] to deny access to your datas.

This project was inspired by the USB Condom, but the problem with those is that they completely cut out the data lines and limit the charge rate to USB 2.0 (500mA). The data lines are used to communicate information about the charger’s power sourcing capabilities to the device. Many manufacturers short D+ and D- together, but Apple applies specific voltages to those lines.

[Scasagrande]‘s USB Wrapper gives you options. You can set it to Dedicated Charging Port, Sony, Open Circuit, or Apple. The super-cool part of this hack is for you Apple fanboys. The bottom slider lets you emulate any Apple charger and use any USB cube (including one you may have made) as long as you have that funny cable in your messenger bag.  The hardware is open source and available at [Scasagrande]‘s repo.

Make the jump to see [Scasagrande]‘s nicely detailed video about the project.

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Piezoelectric Crystal Speaker for Clock Radio Is Alarmingly Easy to Make

cockadoodledooLet’s face it: most of us have trouble getting out of bed. Many times it’s because the alarm isn’t loud enough to rouse us from our viking dreams. [RimstarOrg]‘s homeowner’s association won’t let him keep a rooster in the backyard, so he fashioned a piezoelectric crystal speaker to pump up the volume.

[RimstarOrg]‘s speaker uses a Rochelle salt crystal strapped to a bean can diaphragm. In his demonstration, he begins by connecting an old clock radio directly to the crystal. This isn’t very loud at all, so he adds a doorbell transformer in reverse. This is louder, but it still won’t get [RimstarOrg] out of bed.

Enter the microwave oven transformer. Now it’s sufficiently loud, though it’s no fire bell alarm. He also demonstrates the speaker using a piezo igniter from one of those long barbecue lighters and a crystal radio earpiece. As always, the video is after the jump. [RimstarOrg] has a lot of relevant linkage in the summary so you can learn how to grow your own Rochelle crystals.

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