The Internet Of Christmas Tree Watering

January 1, 2021 by Jenny List 5 Comments

There’s nothing quite like a real Christmas tree, but as anyone who’s had one will know there’s also nothing like the quantity of needles that a real tree can shed when it runs short of water. It’s a problem [RK] has tackled, with a Christmas tree water level monitor that has integration with Adafruit’s cloud service to give a handy phone notification when more watering is required.

The real interest in this project lies in the sensor development path. There are multiple ways of water level sensing from floats and switches through resistive and light scattering techniques, but he’s taken the brave step of using a capacitive approach. Water can be used as a dielectric between two parallel metal plates, and the level of the water varies the capacitance. Sadly the water from your tap is also a pretty good conductor, so the first attempt at a capacitive sensor was not effective. This was remedied with a polythene “sock” for each electrode constructed with the help of a heat sealer. The measurement circuit was simply a capacitive divider fed with a square wave, from which an Adafruit Huzzah board could easily derive an amplitude reading that was proportional to the water level. The board then sends its readings to Adafruit.io, from which a message can be sent to a Slack channel with the notification enabled. All in all a very handy solution.

Plant care is a long-running theme in Hackaday projects, but not all of them need a microcontroller.

The Challenges Of Monitoring Water Streams And Surviving Mother Nature

June 30, 2020 by Danie Conradie 23 Comments

Small waterways give life in the form of drinking and irrigation water, but can also be very destructive when flooding occurs. In the US, monitoring of these waterways is done by mainly by the USGS, with accurate but expensive monitoring stations. This means that there is a limit to how many monitoring stations can be deployed. In an effort to come up with a more cost-efficient monitoring solution, [Rohan Menon] and [Ian Vernooy] created Aquametric, a simple water level, temperature and conductivity measuring station.

The device is built around a Particle Electron that features a STM32 microcontroller and a 3G modem. An automotive ultrasonic sensors measures water level, a thermistor measures temperature and a pair of parallel aluminum plates are used to measure conductivity. All the data from the prototype is output to a live dashboard. The biggest challenges for the system came with field deployment.

The great outdoors can be rather merciless with our ideas and electronic devices. [Rohan] and [Ian] did some tests with LoRa, but quickly found that the terrain severely limited the effective range. Power was another challenge, first testing with a solar panel and lithium battery. This proved unreliable especially at temperatures near freezing, so they decided to use 18 AA batteries instead and optimized power usage.

The mounting system is still an ongoing challenge. A metal pole driven into the riverbed at a wider part ended up bent (probably from ice sheets) and covered in debris to the point that it affected water level readings. They then moved to a narrower and shallower section in the hopes of avoiding debris, but the rocky bottom prevented them from effectively driving in a pole. So the mounted the pole on a steel plate which was then packet with rock to keep it in place. This too failed when it tipped over from rising water levels, submerging the entire sensor unit. Surprisingly it survived with only a little moisture getting inside.

For the 2020 Hackaday Prize, Field Ready and Conservation X Labs have issued challenges that need require some careful consideration and testing to build things that can survive the real world. So go forth and hack!

Water Flow Meter Knows Tank Level

November 11, 2019 by Al Williams 27 Comments

There’s almost always more than one way to get any particular job done. Suppose for instance you have a tank you fill up from a well, and you’d like to know when the time is right to refill the tank. The obvious answer is to measure the level of the tank, and there are plenty of ways to do that. However, [Liam Hanninen] has a different approach. Using a flow meter, he measures how much water leaves the tank. Assuming that you know it was once full, you can deduce how much water is left.

Using a YF-S201 flowmeter on a Raspberry Pi, the code uses Python to populate a database. The meter will need to be calibrated to get an exact volume measurement.

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Steampunk Water Thief Clock Steals Attention, Too

November 8, 2019 by Kristina Panos 7 Comments

The funny thing about clocks is that the more intriguing they are to look at, the more precious time is wasted. This steampunk clepsydra is no exception. A clepsydra, or water thief clock is an ancient design that takes many forms. Any clock that uses the inflow or outflow of water to measure time could be considered a clepsydra, even if it uses electronics like this steampunk version.

[DickB1]’s sticky-fingered timepiece works by siphoning water from the lower chamber into the upper chamber on a one-minute cycle. An MSP430 and a MOSFET control the 12 V diaphragm pump. As the water level rises in the upper chamber, a float in the siphon pushes a lever that moves a ratchet and pawl that’s connected to the minute hand. The hour hand is driven by gears. A hidden magnet and Hall effect sensor help keep the clock clicking at one-minute intervals.

Although [DickB1] doesn’t tell you exactly how to replicate this clock, he offers enough information to get started in designing your own. Take a second to check it out after the break.

Most of the thieving around here is done for the joules, so here’s a joule thief running a clock.

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Grey Water Toilet Helps Keep You Flush

September 16, 2019 by Kristina Panos 43 Comments

The average first world household swims in an ocean of non-potable water from things like HVAC condensation, shower drains, and periods of rain. All of it just goes to waste. These same households pay the city to deliver drinkable water to places that don’t need it, like the toilet tanks. Isn’t it time to put all that perfectly good grey water to use? With a zero city water toilet, you can give that slightly-used H₂O one last hurrah before flushing it down the drain.

When the toilet is flushed, an ultrasonic sensor in the toilet tank monitors the change in water level and triggers a pump to fill the toilet back up from a barrel in the basement. A clear plastic tube inserted into the toilet tank does double duty as both the water source and tank overflow drain point.

The 55-gallon plastic barrel in the basement collects water from both a shallow well and condensation from [nodemcu12ecanada]’s gas furnace. A NodeMCU controls the 12V submersible pump to send water up to the toilet, and another ultrasonic sensor monitors the water level in the barrel.

This setup doesn’t require changes to any of the existing plumbing, and reverting back is easy. We particularly like the use of phone plugs and jacks as quick connectors, and will likely steal the idea. You can get more information about this and [nodemcu12ecanada]’s other home-automation projects here.

A Solar-Powered Box Of Sensors To Last 100 Years

June 25, 2019 by Tom Nardi 58 Comments

It’s a simple goal: build a waterproof box full of environmental sensors that can run continuously for the next century. OK, so maybe it’s not exactly “simple”. But whatever you want to call this epic quest to study and record the planet we call home, [sciencedude1990] has decided to make his mission part of the 2019 Hackaday Prize.

The end goal might be pretty lofty, but we think you’ll agree that the implementation keeps the complexity down to a minimum. Which is important if these solar-powered sensor nodes are to have any chance of going the distance. A number of design decisions have been made with longevity in mind, such as replacing lithium ion batteries that are only good for a few hundred recharge cycles with supercapacitors which should add a handful of zeros to that number.

At the most basic level, each node in the system consists of photovoltaic panels, the supercapacitors, and a “motherboard” based on the ATmega256RFR2. This single-chip solution provides not only an AVR microcontroller with ample processing power for the task at hand, but an integrated 2.4 GHz radio for uploading data to a local base station. [sciencedude1990] has added a LSM303 accelerometer and magnetometer to the board, but the real functionality comes from external “accessory” boards.

Along the side of the main board there’s a row of ports for external sensors, each connected to the ATmega through a UART multiplexer. To help control energy consumption, each external sensor has its own dedicated load switch; the firmware doesn’t power up the external sensors until they’re needed, and even then, only if there’s enough power in the supercapacitors to do so safely. Right now [sciencedude1990] only has a GPS module designed to plug into the main board, but we’re very interested in seeing what else he (and perhaps even the community) comes up with.

Picking The Right Sensors For Home Automation

April 16, 2019 by Maya Posch 22 Comments

Imagine that you’re starting a project where you need to measure temperature and humidity. That sounds easy in the abstract, but choosing a real device out of many involves digging into seemingly infinite details and trade-offs that come with them. If it’s a low-stakes monitoring project, picking the first sensor that comes to mind might suffice. But when the project aims to control an AC system in an office of temperature-sensitive coders, it pays to take a hard look at the source of all information: the sensor.

Continuing a previous article I would like to use that same BMaC project from that article as a way to illustrate how even a couple of greenhorns can figure out how to pick everything from environmental sensors to various actuators, integrating it into a coherent system that in the end actually does what it should.

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