Hackaday Prize 2022: DIY Landslide Warning System

Landslides can be highly dangerous to both people and property. As with most natural disasters, early warning can make all the difference. [Airpocket] has built a cheap, affordable system that hopes to offer just that.

The system relies on a network of sensors built with Sony Spresense controllers, built into solar garden light enclosures which provide a watertight enclosure and a sustainable power supply. The controllers are paired with accelerometers to detect movement, and communicate over a WiSUN connection back to a Raspberry Pi 4B base station. When a deployed sensor station detects movement, it sends a message back to the base station, which sounds the alarm that a landslide may be imminent.

Early testing shows the concept works in theory. In practice, some improvements to reduce power draw and increase communication reliability are required. However, it’s a solid proof of concept for a simple landslide warning system.

Early warning is always key when it comes to things like landslides, tsunamis, and earthquakes. In fact, the US Geological Survey has done its own work on predicting earthquakes and providing early warning, too. Video after the break.

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Water Level Sensor Does Not Use Water Level Sensor

When interfacing with the real world, there are all kinds of sensors available which will readily communicate with your microcontroller of choice. Moisture, pH, humidity, temperature, location, light, and essentially every other physical phenomenon are readily measured with a matching sensor. But if you don’t have the exact sensor you need, it’s sometimes possible to use one sensor as a proxy for another.

[Brian Wyld] needed a way to monitor the level of a remote body of water but couldn’t use a pressure or surface-level sensor, so he used a sensor typically intended for geolocation instead. This particular unit, an STM-type device with a built-in accelerometer, is attached to a rotating arm with a float at one end. As the arm pivots, the microcontroller reports its position and some software converts the change in position to a water level. It’s also paired with a LoRa radio, allowing it to operate off-grid.

Whether there is a design requirement to use an esoteric sensor to measure something more common, or a personal hardware limitation brought about by a shallow parts drawer, there’s often a workaround like this one that can accomplish the job. Whatever the situation, we do appreciate hacking sensors into other types of sensors just as much as anything else.

Tech In Plain Sight: Rain-Sensing Wipers

While it is definitely a first-world problem that you don’t want to manually turn on your windshield wipers when it starts raining, it is also one of those things that probably sounds easier to solve than it really is. After all, you can ask a four-year-old if it is raining and expect a reasonable answer. But how do you ask that question of a computer? Especially a tiny cheap computer that is operating pretty much on its own.

You might want to stop here and try to think of how you’d do it. Measure the conductivity of the glass? Maybe water on the glass affects its dielectric constant and you could measure the resulting capacitance? Modern cars don’t do either. The problem is complicated because you need a solution that works with the glass and isn’t prone to false positives due to dirt or debris.

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The Virtue Of Wires In The Age Of Wireless

We ran an article this week about RS-485, a noise resistant differential serial multidrop bus architecture. (Tell me where else you’re going to read articles like that!) I’ve had my fun with RS-485 in the past, and reading this piece reminded me of those days.

You see, RS-485 lets you connect a whole slew of devices up to a single bundle of Cat5 cable, and if you combine it with the Modbus protocol, you can have them work together in a network. Dedicate a couple of those Cat5 lines to power, and it’s the perfect recipe for a home, or hackerspace, small-device network — the kind of things that you, and I, would do with WiFi and an ESP8266 today.

Wired is more reliable, has fewer moving parts, and can solve the “how do I get power to these things” problem. It’s intrinsically simpler: no radios, just serial data running as voltage over wires. But nobody likes running cable, and there’s just so much more demo code out there for an ESP solution. There’s an undeniable ease of development and cross-device compatibility with WiFi. Your devices can speak directly to a computer, or to the whole Internet. And that’s been the death of wired.

Still, some part of me admires the purpose-built simplicity and the bombproof nature of the wired bus. It feels somehow retro, but maybe I’ll break out some old Cat5 and run it around the office just for old times’ sake.

An anemometer outside

DIY Anemometer For Projects Big And Small

When [Fab] needed an anemometer for his latest project, he was stymied by the limited range and relatively high prices of commercial options. Undeterred, his solution was an impressive DIY anemometer that rivals the off-the-shelf alternatives.

AnemoSens was designed from the ground up as a component for the ambitious WinDIY_2 Horizontal Axis Wind Turbine, however it’s just as suitable as part of your standard home weather station. The microcontroller unit uses RS485/Modbus connectivity, ensuring that data from the wind sensor is accessible across a variety of platforms. Serial-stream via USB and an SD cart slot are also available for recording data, the latter being particularly useful for long-term unsupervised monitoring. [Fab] also integrated an ESP32 for recording data over the air.

The MCU also features a location for the venerable BME280, which is a relatively accurate temperature, pressure and humidity sensor often deployed in DIY weather stations. This feels like a nice touch, as it means the anemometer package alone could feasibly serve as a rudimentary weather sensing station, or as a backup for more elaborate environmental monitoring.

The prototype currently uses a Hall effect sensor for measuring the wind speed, while a AS5048B magnetic rotary encoder does a decent job of measuring rotation (wind direction). Some calibration is likely necessary to improve the accuracy of this setup, but it’s a promising start.

[Fab] has already identified some shortcomings with the bearing, but has a plan for future iterations. He might want to check out this spare-parts anemometer that uses a bearing from an old hard drive.

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Winners Of Hackaday’s Data Loggin’ Contest: Bluetooth Gardening, Counting Cups, And Predicting Rainfall

The votes for Hackaday’s Data Loggin’ Contest have been received, saved to SD, pushed out to MQTT, and graphed. Now it’s time to announce the three projects that made the most sense out of life’s random data and earned themselves a $100 gift certificate for Tindie, the Internet’s foremost purveyor of fine hand-crafted artisanal electronics.

First up, and winner of the Data Wizard┬ácategory, is this whole-garden soil moisture monitor by [Joseph Eoff]. You might not realize it from the picture at the top of the page, but lurking underneath the mulch of that lovely garden is more than 20 Bluetooth soil sensors arranged in a grid pattern. All of the data is sucked up by a series of solar powered ESP32 access points, and ultimately ends up on a Raspberry Pi by way of MQTT. Here, custom Python software generates a heatmap that indicates possible trouble spots in the garden. With its easy to understand visualization of what’s happening under the surface, this project perfectly captured the spirit of the category.

Next up is the Nespresso Shield from [Steadman]. This clever gadget literally listens for the telltale sounds of the eponymous coffee maker doing its business to not only estimate your daily consumption, but warn you when the machine is running low on water. The clever non-invasive method of pulling data from a household appliance made this a strong entry for the Creative Genius category.

Last but certainly not least is this comprehensive IoT weather station that uses machine learning to predict rainfall. With crops and livestock at risk from sudden intense storms, [kutluhan_aktar] envisions this device as an early warning for farmers. The documentation on this project, from setting up the GPRS-enabled ESP8266 weather station to creating the web interface and importing all the data into TensorFlow, is absolutely phenomenal. This project serves as a invaluable framework for similar DIY weather detection and prediction systems, which made it the perfect choice for our World Changer category.

There may have only been three winners this time around, but the legendary skill and creativity of the Hackaday community was on full display for this contest. A browse through the rest of the submissions is highly recommended, and we’re sure the creators would love to hear your feedback and suggestions in the comments.

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Practical Sensors: The Many Ways We Measure Heat Electronically

Measuring temperature turns out to be a fundamental function for a huge number of devices. You furnace’s programmable thermostat and digital clocks are obvious examples. If you just needed to know if a certain temperature is exceeded, you could use a bimetalic coil and a microswitch (or a mercury switch as was the method with old thermostats). But these days we want precision over a range of readings, so there are thermocouples that generate a small voltage, RTDs that change resistance with temperature, thermistors that also change resistance with temperature, infrared sensors, and vibrating wire sensors. The bandgap voltage of a semiconductor junction varies with temperature and that’s predictable and measurable, too. There are probably other methods too, some of which are probably pretty creative.

Bimetalic coil by [Hustvede], CC-BY-SA 3.0.
You can often think of creative ways to do any measurement. There’s an old joke about the smart-alec student in physics class. The question was how do you find the height of a building using a barometer. One answer was to drop the barometer from the top of the building and time how long it takes to hit the ground. Another answer — doubtlessly an engineering student — wanted to find the building engineer and offer to give them the barometer in exchange for the height of the building. By the same token, you could find the temperature by monitoring a standard thermometer with a camera or even a level sensor which is a topic for another post.

The point is, there are plenty of ways to measure anything, but in every case, you are converting what you want to know (temperature) into something you know how to measure like voltage, current, or physical position. Let’s take a look at how some of the most interesting temperature sensors accomplish this.

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