Open Source Electric Vehicle Charging

April 6, 2021 by Bryan Cockfield 26 Comments

Electric vehicles are becoming more and more common on the road, but when they’re parked in the driveway or garage there are still some kinks to work out when getting them charged up. Sure, there are plenty of charging stations on the market, but they all have different features, capabilities, and even ports, so to really make sure that full control is maintained over charging a car’s batteries it might be necessary to reach into the parts bin and pull out a trusty Arduino.

This project comes to us from [Sebastian] who needed this level of control over charging his Leaf, and who also has the skills to implement it from the large high voltage switching contactors to the software running its network connectivity and web app. This charging station has every available feature, too. It can tell the car to charge at different rates, and can restrict it to charging at different times (if energy is cheaper at night, for example). It is able to monitor the car’s charge state and other information over the communications bus to the vehicle, and even has a front-end web app for monitoring and controlling the device.

The project is based around an Arduino Nano 33 IoT with all of the code available on the project’s GitHub page. While we would advise using extreme caution when dealing with mains voltage and when interfacing with a high-ticket item like an EV, at first blush the build looks like it has crossed all its Ts and might even make a good prototype for a production unit in the future. If you don’t need all of the features that this charging station has, though, you can always hack the car itself to add some more advanced charging features.

Continue reading “Open Source Electric Vehicle Charging” →

Smart Lid Spies On Sourdough Starter, Sends Data Wirelessly

March 4, 2021 by Donald Papp 16 Comments

[Justin Lam] created a wonderfully-detailed writeup of his Smart Sourdough Lid project, which was created out of a desire to get better data on the progress and health of his sourdough starters, and to do so more efficiently. The result is a tidy, one-piece lid that constantly measures temperature, humidity, and height of the starter in the jar. Data is sent wirelessly for analysis, but there is also a handy OLED display on the top of the lid that shows immediately useful data like how much the starter has peaked, and how much time has passed since it did so.

The PCB was optimized for size, and not designed with mounting in mind, so a hot-glued machine screw serves as a “button extender”. Issues like this can happen when enclosures are designed after the fact; it’s something to which we can all relate.

We really like how focused the design is, and the level of detail [Justin] goes into to explain his design decisions and describe how well they worked out. This isn’t [Justin]’s first kick at the can when it comes to getting data on his sourdough, after all. We remember his earlier work using computer vision to analyze sourdough starters, and he used what he learned to inform this new design; the smart lid is easier to use and handles data much more efficiently.

The project’s GitHub repository has all the information needed to build your own. The lid is ESP8266-based and integrates a VL6180X time-of-flight (ToF) distance sensor, DHT22 to sense temperature and humidity, and a small SSD1306 OLED display for data. A small custom PCB keeps the modules tidy, and a 3D-printed custom enclosure makes it one tidy package.

[Justin] also analyzes the results he obtained and talks about what they mean in the last part of his writeup, so if you’re into baking and interested in his findings, be sure to give that a look.

A Smart Way To Wire Smart Switches

February 19, 2021 by Lewin Day 33 Comments

Smart switches are fun, letting you control lights and appliances in your home over the web or even by voice if you’re so inclined. However, they can make day-to-day living more frustrating if they’re not set up properly with regards to your existing light switches. Thankfully, with some simple wiring, it’s possible to make everything play nice.

The method is demonstrated here by [MyHomeThings], in which an ESP8266 is used with a relay to create a basic smart switch. However, it’s wired up with a regular light switch in a typical “traveller” multiway switching scheme – just like when you have two traditional light switches controlling the same light at home. To make this work with the ESP8266, though, the microcontroller needs to be able to know the current state of the light. This is done by using a 240V to 3.3V power supply wired up in parallel with the light. When the light is on, the 3.3V supply is on. This supply feeds into a GPIO pin on the ESP8266, letting it know the light’s current state, and allowing it to set its output relay to the correct position as necessary.

This system lets you use smart lighting with traditional switches with less confused flipping, which is a good thing in our book. If you’re using standalone smart bulbs, however, you could consider flashing them with custom firmware to improve functionality. As always, if you’ve got your own neat smart lighting hacks, be sure to let us know!

Old Gas Meter Gets Smart With The ESP8266

January 31, 2021 by Anool Mahidharia 34 Comments

Measuring the usage of domestic utilities such as water, gas or electricity usually boils down to measuring a repetitive pulse signal with respect to time. To make things easy, most modern utility meters have a pulsed LED output, which can be used to monitor the consumption by using an external optical sensor. But what do you do if your meter isn’t so cooperative?

That’s exactly what [Francesco] had to figure out while developing the non-invasive gas tracking system he calls ESPmeter. His meter might not have an LED, but it did have a magnet attached to the counter disk which activated an internal hall sensor. With some hacking, he was able to attach an external Hall-effect sensor to pick up this magnet and use the signal to monitor his daily gas consumption.

A big stumbling block in such projects is the issue of powering the device for an extended period, and remembering when it’s time to change the batteries. With the clever use of commonly available parts, he was able to reduce power consumption allowing three AA batteries to last about a year between changes. For one thing, he uses an ATtiny13 to actually read the sensor values. The chip doesn’t run continuously, its watchdog is set at 1 Hz, ensuring that the device is woken up often enough so that it has time to power up the sensor and detect the presence of the magnet. Battery voltage is also measured via a voltage divider connected to the chip’s ADC pin.

At regular intervals throughout the day, the ESP8266 polls the ATtiny13 to pull the stored sensor pulses and voltage measurement. Then at midnight, the ESP transmits all the collected data to a remote server. Overall, this whole scheme allows [Francesco] to reliably gather his gas consumption data while not having to worry about batteries until he gets the low voltage notification. Since the data visualization requirements are pretty basic, he is keeping things simple by using Plotly to display his time series data.

If you are unfortunate enough to have an even older meter which doesn’t use optical or magnetic rotation sensing, you can use a disassembled mouse to keep track of the Gas Meter.

Hackaday Links: December 20, 2020

December 20, 2020 by Dan Maloney 11 Comments

If development platforms were people, Google would be one of the most prolific serial killers in history. Android Things, Google’s attempt at an OS for IoT devices, will officially start shutting down on January 5, 2021, and the plug will be pulled for good a year later. Android Things, which was basically a stripped-down version of the popular phone operating system, had promise, especially considering that Google was pitching it as a secure alternative in the IoT space, where security is often an afterthought. We haven’t exactly seen a lot of projects using Android Things, so the loss is probably not huge, but the list of projects snuffed by Google and the number of developers and users left high and dry by these changes continues to grow. Continue reading “Hackaday Links: December 20, 2020” →

Speaker Snitch Tattles On Privacy Leaks

December 9, 2020 by Bryan Cockfield 33 Comments

A wise senator once noted that democracy dies with thunderous applause. Similarly, it’s also how privacy dies, as we invite more and more smart devices willingly into our homes that are built by companies that don’t tend to have our best interests in mind. If you’re not willing to toss all of these admittedly useful devices out of the house but still want to keep an eye on what they’re doing, though, [Nick Bild] has a handy project that lets you keep an eye on them when they try to access the network.

The device is built on a Raspberry Pi that acts as a middle man for these devices on his home network. Any traffic they attempt to send gets sent through the Pi which sniffs the traffic via a Python script and is able to detect when they are accessing their cloud services. From there, the Pi sends an alert to an IoT Arduino connected to an LED which illuminates during the time in which the smart devices are active.

The build is an interesting one because many smart devices are known to listen in to day-to-day conversation even without speaking the code phrase (i.e. “Hey Google” etc.) and this is a great way to have some peace-of-mind that a device is inactive at any particular moment. However, it’s not a foolproof way of guaranteeing privacy, as plenty of devices might be accessing other services, and still other devices have even been known to ship with hidden hardware.

Continue reading “Speaker Snitch Tattles On Privacy Leaks” →

Roll Your Own Tracking

December 8, 2020 by Matthew Carlson 35 Comments

The smartphone is perhaps the signature device of our modern lives. For most of the population it is never more than an arm’s length away, it’s on your person more than any other device in your life. Smartphones are packed with all sorts of radios and ways to communicate wireless. [Amine Mansouri] built an ESP8266 based tracking device that takes advantage of this.

Most WiFi-enabled devices will send out “probe requests” frames trying to search for the SSIDs they were connected to. These packets contain the device MAC address as well as the SSIDs you’ve connected to. Using about 12 components, [Amine] laid out a small board in Eagle. By putting the ESP8266 in monitor mode, the probe frames can be logged and uploaded. The code can be updated OTA making it easy to service while in the field.

With permission from his local library, eight repeater boards were scattered throughout the building to forward the probe packets to where the tracker could pick them up. A simple web interface was built that allows the library to figure out how many people are in the library and how often they frequent the premises.

While an awesome project with open-source code on Github, it is important to stress how important is it to get permission to do this kind of tracking. While some phones implement MAC randomization, there are still many out in the wild that don’t. While this is similar to another project that listens to radio signals to determine the coming and going of ships and planes, tracking people with this sort of granularity is in a different category altogether.

Thanks [Amine] for sending this one in!