Tearing Into Delta Sigma ADC’s

July 7, 2016 by Bil Herd 33 Comments

It’s not surprising that Analog to Digital Converters (ADC’s) now employ several techniques to accomplish higher speeds and resolutions than their simpler counterparts. Enter the Delta-Sigma (Δ∑) ADC which combines a couple of techniques including oversampling, noise shaping and digital filtering. That’s not to say that you need several chips to accomplish this, these days single chip Delta-Sigma ADCs and very small and available for a few dollars. Sometimes they are called Sigma-Delta (∑Δ) just to confuse things, a measure I applaud as there aren’t enough sources of confusion in the engineering world already.

I’m making this a two-parter. I will be talking about some theory and show the builds that demonstrate Delta-Sigma properties and when you might want to use them.

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The Champagne Of Light Bulbs

July 7, 2016 by Jenny List 9 Comments

We’re all used to making our own lighting projects. Triac dimmers, LEDs, Neopixels, EL wire, there is a huge array of lighting components and technologies at our fingertips. But how many of us have made our own lighting rather than buying off-the-shelf? [Confined Maker] set out to do just that by creating an incandescent light bulb from scratch, and since he’s obviously a hacker with a bit of class he did it in an empty Dom Perignon champagne bottle.

It might seem a daunting project, but as he shows us in the video below the break, it turns out to be surprisingly straightforward with no exotic tooling required. He starts by winding a fine coil of thin tungsten wire round a dowel to act as his filament, before bringing a pair of enameled copper wires through holes drilled in the base of the bottle and out of the neck. The ends of these wires are then spliced to his filament and secured with conductive epoxy before the whole assembly is carefully slid back into the bottle. The holes are caulked with silicone, and the bottle is then carefully charged with argon. Argon is heavier-than-air, so he can do this on the bench with nothing more than a bicycle tube inflator and a drinking straw. The bottle is then sealed with a cork and more silicone, and his bulb is ready.

The first power-up with 120V mains power sees a puff of smoke inside the bottle as a coating on the tungsten is vapourised, but after that the bulb does its job well. He’s concerned about his epoxy melting, and the filament has moved to one side of the bottle so he’s not sure about the lifetime he can expect, but to make a working light bulb with such basic equipment is still an impressive accomplishment. His video below the break is eleven and a half minutes long, but well worth watching every minute.

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Dumbing Down A Smart Switch

July 7, 2016 by Elliot Williams 53 Comments

Internet of Everything is the way to go for home automation these days. ITEAD makes an ESP-8266 switch that IoT-ifies your appliances. If you still have an ancient, 433 MHz style radio switch system, they even make one that does WiFi and 433 MHz. But if you’re too cheap to shell out for the dual-mode version, you can always add a $1 433 MHz radio yourself. Or at least, that’s what [Tinkerman] did.

Aside from the teardown and reverse-engineering of the WiFi-enabled switch, [Tinkerman] also flashed custom firmware into the switch’s ESP-8266, and worked it all into his existing home Node-RED framework. Now he’s got more possible ways to turn on his living-room lights than any person could possibly hope for!

If you want to get into this whole WiFi-based home automation game, you could do worse than to have a look at the series we ran on MQTT just a little while ago. Seeing [Tinkerman]’s Node-RED demo makes us think that we’ll have to give that a look for our home system as well.