Solenoids and Servos for Self Actuated Switches

The new hotness in home automation is WiFi controlled light switches. Sure, we’ve had computer-controlled home lighting for literally forty years with X10 modules, but now we have VC money pouring into hardware, and someone needs to make a buck. A few years ago, [Alex] installed WiFi switches in a few devices in his house and discovered the one downside to the Internet of Light Switches — his light switches didn’t have a satisfying manual override. Instead of cursing the darkness for want of an Internet-connected candle, [Alex] did the only sensible thing. He installed electromagnets, solenoids, and servos behind the light switches in his house.

The exact problem [Alex] is trying to solve here is stateful wall switches. With an Internet-connected lamp socket, the wall switch no longer functions. Being able to turn on a light when your phone is out of charge is something we all take for granted, and the solution is, of course, to have Internet-connected switches.

Being able to read the state of a switch and send some data off to a server is easy. For this, [Alex] used a WeMos D1 mini, a simple ESP8266-based board. The trick here, though, is stateful switches that can toggle themselves on and off. This is a mechanical build, and although self-actuated switches that can flip up and down by computer command exist, they’re horrifically expensive. Instead, [Alex] went the DIY route, first installing electromagnets behind the switches, then moving to solenoids, and finally designing a solution around four cheap hobby servos. The entire confabulation stuffed into a 2-wide electrical box consists of two switches, four hobby servos, the D1 mini, and an Adafruit servo driver board.

The software stack for this entire setup includes a NodeJS server connected to Orvibo Smart Sockets over UDP. Also on this server is a WebSocket server for browser-based clients that want to turn the lights on and off, a FauXMo server to turn the lights on and off via an Amazon Echo via WeMo emulation, and an HTTP server for other clients like [Alex]’ Pebble Watch.

This is, without question, the most baroque method of turning a lamp on and off that we’ve ever seen. Despite this astonishing complexity, [Alex] has something that is also intuitive to use and, to borrow an applhorism, ‘Just Works’. With a setup like this, anyone can flick a switch and turn a lamp on or off over the Internet, or vice-versa. This is the best Home Automation build we’ve ever seen.

You can check out [Alex]’ video demo of his build below, or his GitHub for the entire project here.

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Hackers vs. Mold: Building a Humidistat Fan

Having a mold problem in your home is terrible, especially if you have an allergy to it. It can be toxic, aggravate asthma, and damage your possessions. But let’s be honest, before you even get to those listed issues, having mold where you live feels disgusting.

You can clean it with the regular use of unpleasant chemicals like bleach, although only with limited effectiveness. So I was not particularly happy to discover mold growing on the kitchen wall, and decided to do science at it. Happily, I managed to fix my mold problems with a little bit of hacker ingenuity.

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The Internet of Jack-O’-Lanterns

As the candy rush fades, the Halloween hacks continue pouring in. [Jeremy S Cook] has taken a few fundamental concepts and dressed them up inside the smartest pumpkin on the block.

This pumpkin has a WEMOS D1 Mini ESP8266 brain, LED eyes in place of a candle for illumination, and a small USB power bank for power. The code [Cook] is using is a modified sketch by YouTuber [Innovative Tom], which creates a server on your network — don’t forget to insert your network credentials! — that enable control of the LEDs from your computer or smart phone.

[Cook] has wired the LEDs to the relevant pins on the D1 Mini, zip-tied the battery and board together and stuff them in a plastic bag to keep them dry. Stick that into the pumpkin, hot glue the LEDs in place, and test it out!

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Instrument Packed Pedal Keeps Track of Cyclist’s Power

Exactly how much work is required to pedal a bike? There are plenty of ways to measure the power generated by a cyclist, but a lot of them such as heavily instrumented bottom brackets and crank arms, can be far too expensive for casual use. But for $30 in parts you can build this power-measuring bike pedal. and find out just how hard you’re stoking.

Of course it’s not just the parts but knowing what to do with them, and [rabbitcreek] has put a lot of thought and engineering into this power pedal. The main business of measuring the force applied to the crank falls to a pair of micro load cells connected in parallel. A Wemos, an HX711 load-cell amp, a small LiPo pack and charging module, a Qi wireless charger, a Hall sensor, a ruggedized power switch, and some Neopixels round out the BOM. Everything is carefully stuffed into very little space in a modified mountain bike pedal and potted in epoxy for all-weather use. The Hall sensor keeps tracks of the RPMs while the strain gauges measure the force applied to the pedal, and the numbers from a ride can be downloaded later.

We recall a similar effort using a crank studded with strain gauges. But this one is impressive because everything fits in a tidy package. And the diamond plate is a nice touch.

Fight Mold and Mildew with an IoT Bathroom Fan

Delicious sheets of wallboard coated with yummy latex paints, all kept warm and moist by a daily deluge of showers and habitually forgetting to turn on the bathroom exhaust fan. You want mildew? Because that’s how you get mildew.

Fed up with the fuzzy little black spots on the ceiling, [Innovative Tom] decided to make bathroom ventilation a bit easier with this humidity-sensing IoT control for his bathroom exhaust fan. Truthfully, his build accomplishes little more than a $15 timer switch for the fan would, with one critical difference — it turns the fan on automatically when the DHT11 sensor tells the WeMos board that the relative humidity has gone over 60%. A relay shield kicks the fan on until the humidity falls below a set point. A Blynk app lets him monitor conditions in the bathroom and override the automatic fan, which is handy for when you need it for white noise generation more than exhaust. The best part of the project is the ample documentation and complete BOM in the description of the video below, making this an excellent beginner’s project.

No bathroom fan? Not a problem — this standalone humidity-sensing fan can help. Or perhaps you have other bathroom ventilation needs that this methane-sensing fan could help with?

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Attack on the Clones: A Review of Two Common ESP8266 Mini D1 Boards

ESP8266-based development boards have proliferated rapidly. One favorite, the WEMOS Mini-D1 is frequently imitated and sold without any branding. As these boards continue to ship to hobbyists and retailers around the world, we thought it might be interesting to conduct a little experiment.

There are a few ESP8266 development boards available, and the most popular seem to be the NodeMCU ‘Amica’ board. Of course, there are dozens of other alternatives including the WiFiMCU, Sparkfun’s ESP8266 Thing, and Adafruit’s HUZZAH ESP8266. Given that, why is this review limited to the Mini D1 boards? Because the Mini D1 is the cheapest. Or was, until it was cloned.

We took a look at some of these ‘clone’ boards to figure out the differences, find out if they work as intended, and perhaps most importantly, are these clone boards shipped out reliably. What are the results? Check that out below.

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Hands-On the Hot New WeMos ESP-32 Breakout

Just two weeks ago our favorite supplier of cheap ESP8266 boards, WeMos, released the long-awaited LOLIN32 ESP-32 board, and it’s almost a killer. Hackaday regular [deshipu] tipped us off, and we placed an order within minutes; if WeMos is making a dirt-cheap ESP32 development board, we’re on board! It came in the mail yesterday. (They’re out of stock now, more expected soon.)

If you’ve been following the chip’s development, you’ll know that the first spin of ESP-32s had some silicon bugs (PDF) that might matter to you if you’re working with deep sleep modes, switching between particular clock frequencies, or using the brown-out-reset function. Do the snazzy new, $8, development boards include silicon version 0 or 1? Read on to find out!

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