Building An ESP8266 Doorbell On Hard Mode

January 7, 2019 by Tom Nardi 29 Comments

It certainly seems as though it should be an easy enough project; all [Miguel De Andrade] wanted was to receive a notification when somebody was pressing his doorbell, and thought it would be a good project to get his feet wet in the wonderful world of ESP8266 hacking. But as fate would have it, not everything went according to plan. In the end he got it sorted out, but it’s an interesting look at how even the “easy” projects can call the gremlins out of hiding.

Arguably, the problems started when [Miguel] picked up an ESP-01 module from a local electronics retailer. While the convenience of buying the hardware in a brick and mortar store can’t be overstated, it did mean he was stuck with a slightly more spartan experience compared to the more common ESP “development boards”. Programming it externally with a Teensy ended up not being much of an obstacle, but it did mean he was stuck with only two GPIO pins.

At any rate, with ESP in hand, the next step was figuring out how the existing bell and intercom system even worked. Unfortunately, after some experimentation [Miguel] found there was a bit more going on there than he’d hoped. According to his multimeter, the one line from the intercom sits at approximately 5 VDC when it’s open, and drops down to 2.5 VDC when pressed. If that wasn’t bad enough, picking up the handset to answer the intercom sent the voltage up to a microcontroller-killing 12 VDC. To complicate maters further, the supply line for the intercom was 23 VAC, so he’d need to rectify that somehow if he wanted to avoid a separate power supply for the ESP.

To turn this jumble of voltages into a nice clean 0 – 3.3 V signal for the ESP8266, he came up with a circuit based around the LM358 comparator that utilizes an LM117 regulator to power itself and the ESP at the same time. A couple of diodes are there to block the AC component from causing trouble, and an A2N2222A transistor is used as a buffer amplifier to boost the output of the comparator so it registers as a digital HIGH on the ESP. The circuit took a bit of fiddling to get sorted out, but in the end [Miguel] says it seems to get the job done.

You might think the problems were solved, but this is where it gets really annoying. The system would work fine for awhile, and then inexplicably go silent. In diagnosing the problem he realized that his circuit connected to GPIO_0 was inadvertently putting the ESP8266 into programming mode, since it was holding the pin LOW unless the intercom button was pressed. He assumed he could just move the circuit to the other GPIO pin, but as that one has the board’s LED on it, that caused its own problems. For now, [Miguel] hasn’t come up with a solution to this issue, and has learned to live with the fact that the system won’t come back up cleanly should it lose power for any reason.

If you’re looking for a slightly classier look than a scrap of perfboard stuck on the wall with what appears to be chewing gum, we’ve also seen the ESP8266 used in some more ornate doorbell setups. Of course if you still haven’t gotten your head wrapped around the whole Internet-connected button thing, you can always start with something a little easier.

Controlling Non-Googley Devices With Google Assistant

January 7, 2019 by Richard Baguley 14 Comments

In the near future of the Smart Home, you will be able to control anything with your voice. Assuming that everything supports the Smart Home standard you chose, that is. If you have a device that supports one of the other standards, you’ll end up uselessly yelling at it. Unless you use gBridge. As the name suggests, gBridge is a bridge between Google Assistant devices and the rest of the smart home universe. It’s an open source project that is available as a Docker image can be run on a low power device in the home, or on a hosted service.

Fundamentally, gBridge is a Google Assistant to MQTT translator. Message Queuing Telemetry Transport (MQTT) is the messaging protocol that many smart home devices use, as it runs over TCP and doesn’t take much power to implement. We’ve covered how to bash around in MQTT and do much of this yourself here, but gBridge looks to be somewhat easier to use. It’s just come out of beta test, and it looks like it might be a good way to get into Smart Home hacking.

There are, of course, plenty of other ways of doing this, such as IFFFT, but [Peter Kappelt], the brains behind gBridge, claims that it is more flexible, as it offers support for the whole Google Assistant vocabulary, so you can do things like put devices into groups or do more conditional control (such as if the light level in the hallway rises above a certain amount, start recording with a camera) with non-Google devices. [Peter] is also looking to run gBridge as a hosted service, where he does the behind the scenes stuff to update servers, etc, in return for a small fee.

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Build A Home Automation Hub For $20

January 5, 2019 by Eric Evenchick 43 Comments

With so many WiFi home automation devices on the market, you might want to take advantage of these low cost products without having to send your data to third-party servers. This can be accomplished by running your own home automation hub on your home network.

If you don’t want to use a full computer for this purpose, [Albert] has you covered. He recently wrote a guide on running Domoticz on the $20 GL-MT300Nv2 pocket router.

The setup is rather simple: just perform a firmware update on your router using the provided image and a full home automation stack is installed. Domoticz provides a web interface for configuring your devices, setting up rules, and viewing sensor data.

The pocket router is also supported by OpenWrt and provides a USB host port, making it a low-cost option for any WiFi hack you might have in mind. We’ve seen quite a few OpenWrt based hacks over the years.

The Mystery Of The Clacking Clanking Scraping Sound

January 4, 2019 by Lewin Day 47 Comments

Hackers tend to face household problems a little differently than ordinary folk. Where the average person sees a painful repair bill or a replacement appliance, the hacker sees a difficult troubleshooting job and the opportunity to save some cash. [trochilidae] was woken one day by the dreaded Clacking Clanking Scraping Sound, or CCSS, and knew that something had to be done.

[trochilidae] reports that usually, the CCSS is due to the child of the house destroying his lodgings, but in this case, the source was laundry based. The Miele tumble dryer was acting up, and in need of some attention. What follows is a troubleshooting process [AvE] would be proud of – careful disassembly to investigate the source of the problem. Initial efforts found a loose bulb that was unrelated, before landing on a mysterious spring that wouldn’t fit back into place. In the end, that’s because it had no right to be there at all – an underwire had escaped from a bra, before becoming entangled in the dryer’s bearing. With the culprit identified and removed, it was a simple reassembly job with some attention also paid to the condenser and filters to keep things in ship-shape.

It just goes to show – a bad noise, if properly investigated in a prompt manner, doesn’t have to be the end of the world. A bit of investigation goes a long way, and can save you a lot of money and heartache.

We’ve seen appliances giving hackers trouble before – like this aging washing machine that got its mechanical brain replaced with an Arduino.

Reset Your Router The Modern Way

January 3, 2019 by Jenny List 35 Comments

Many Hackaday readers will be settling back into their lives after a holiday period crammed into some family matriarch’s house along with too many assorted relatives, having given up their speedy internet connection for whatever passes for broadband wherever Granny lives. The bargain-basement router supplied by the telephone company will have spent the period wilting under the pressure of a hoard of teenagers watching other teenagers inanities on YouTube, and the Christmas ritual of Resetting The Router will have been performed multiple times.

A very simple schematic for the resetter.

Wouldn’t it be nice if your router simply reset itself every time it crashed or the Internet connection went down? [Cyb3rn0id] has a solution (Italian original here), in the form of an ESP8266 that pings an online service every few seconds, and turns the router off and on again via a power relay in the event that the ping attempt is repeatedly unsuccessful. It’s brilliantly simple, requiring only a single GPIO and a MOSFET to fire the relay with an LED indicator for good measure, and it’s built upon a piece of prototyping board. The router power is switched on the low-voltage side for safety.

The software is pretty basic and has the WiFi credentials hard-coded into it, so we’re guessing a version with a web interface could be built. But as a personal device for easing the pain of router crashes it gets our vote despite that shortcoming.

This isn’t the first router resetter we have seen here, but a previous model still required human intervention.

Neural Network Knows When Cat Wants To Go Outside

December 21, 2018 by Lewin Day 38 Comments

Neural networks are computer systems that are vaguely inspired by the construction of animal brains, and much like human brains, can be trained to obey the whims of the almighty domestic cat. [EdjeElectronics] has built just such a system, and his cat is better off for it.

The build uses a Raspberry Pi, fitted with the Pi Camera board, to image the area around the back door of the house. A Python script regularly captures images and passes them to a TensorFlow neural network for object recognition. The TensorFlow network returns object type and positions to the Python script. This information can be used to determine if there is a cat in the frame, and if it is inside or outside. If the cat remains in position for ten consecutive frames, a text message is sent via Twilio, indicating to the owner to let the cat in or out, as the case may be.

Thirty years ago, object classification was a pie-in-the-sky technology, but now you can run it on a $30 computer to figure out where your pets are. What a time we live in! A similar solution to this problem may be a cat door that unlocks via facial recognition. Video after the break.

[Thanks to Baldpower for the tip!]

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The Hydrogen Economy May Be Coming Through Your Cooker

December 17, 2018 by Jenny List 106 Comments

About an hour’s drive from where this is being written there is a car plant, and as you drive past its entrance you may notice an unobtrusive sign and an extra lane with the cryptic road marking “H2”. The factory is the Honda plant at Swindon, it produces some of Europe’s supply of Civics, and the lane on the road leads to one of the UK or indeed the world’s very few public hydrogen filling stations. Honda are one of a select group of manufacturers who have placed a bet on a future for environmentally sustainable motoring that lies with hydrogen fuel cell technologies.

The hydrogen-powered Honda Clarity FCV, a car most of us will probably never see. Lcaa9 [CC BY-SA 4.0].

The trouble for Honda and the others is that if you have seen a Honda Clarity FCV or indeed any hydrogen powered car on the road anywhere in the world then you are among a relatively small group of people. Without a comprehensive network of hydrogen filling stations such as the one in Swindon there is little incentive to buy a hydrogen car, and of course without the cars on the road there is little incentive for the fuel companies to invest in hydrogen generating infrastructure such as the ITM Power electrolysis units that seem to drive so many of the existing installations. By comparison an electric car is a much safer bet; while the charging point network doesn’t rival the gasoline filling station network there are enough to service the electric motorist and a slow charge can be found from most domestic supplies. Continue reading →