Remote MQTT Temperature Sensor Shows How It’s Done

First of all, there are definitely simpler ways to monitor remote temperatures, but [Mike]’s remote MQTT temperature sensor and display project is useful in a few ways. Not only does it lay out how to roll such a system from scratch, but it also showcases system features like solar power.

After all, if one simply wants to monitor temperature that’s easily done, but once one wishes to log those temperatures and use them to trigger other things, then rolling one’s own solution starts to get more attractive. That’s where using someone else’s project as a design reference can come in handy.

[Mike’s] solution uses two Wemos D1 boards: one with a DS18B20 temperature sensor for outdoors, and one with a small OLED screen for an interior display. The external sensor relies on a rechargeable 18650 cell and a solar panel for a hassle-free power supply, and the internal sensor (of which there can be many) has a cute enclosure and is powered by USB. On the back end, a Raspberry Pi running an MQTT gateway and Node Red takes care of the operational side of things. The whole system has been happily running for over two years.

What is MQTT? It is essentially a messaging protocol, and takes care of the whole business of reliably communicating data back and forth between IoT devices. It scales very well and doesn’t need to be hard or intimidating; our own [Elliot Williams] can tell you all about implementing it.

A mailbox with a solar cell on top

IoT-Enabled Mailbox Lets You Check Your Mail Without Leaving Your House

Whether you live in an apartment downtown or in a detached house in the suburbs, if your mailbox is not built into your home you’ll have to go outside to see if anything’s there. But how do you prevent that dreadful feeling of disappointment when you find your mailbox empty? Well, we’re living in 2022, so today your mailbox is just another Thing to connect to the Internet of Things. And that’s exactly what [fhuable] did when he made a solar powered IoT mailbox.

The basic idea was to equip a mailbox with a camera and have it send over pictures of its contents. An ESP32-Cam module could do just that: with a 1600 x 1200 camera sensor, a 160 MHz CPU and an integrated WiFi adapter, [fhuable] just needed to write an Arduino sketch to have it take a picture every few hours and upload it to an FTP server.

A pile of components making up an IoT Mailbox
The components inside: a solar cell, battery, power controller, LDO and ESP32-Cam module with WiFi antenna

But since running a long cable all the way from the house was not an attractive option, the whole module had to be completely wireless. [fhuable] decided to power it using a single 18650 lithium ion cell, which gets topped up continuously thanks to a 1.5 W solar panel mounted on the roof of the mailbox. The other parts are housed in a 3D-printed enclosure that’s completely sealed to keep out moisture.

The enclosure had to be made from a material that does not degrade in direct sunlight, which is why [fhuable] decided to try ASA filament; this should be very resistant against UV rays, but proved tricky to process. It warped so much during cooling that the only way to get a solid piece out of the printer was to enclose the entire machine in a cardboard box to keep it warm inside.

The end result was worth it though: a neat little extension on the back of the mailbox that should keep sending photos of its insides for as long as the Sun keeps shining. The camera should also give a good indication as to the contents of the mailbox, allowing the user to ignore any junk mail; this is a useful improvement over previous IoT-enabled mailboxes that use proximity sensors, microswitches or optical sensors.

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Filament Dry Box Design Goes Way Over The Top

There’s a fine line between simple feature creep and going over the top when it comes to project design. It’s hard to say exactly where that line is, but we’re pretty sure that this filament dry box has at least stepped over it, and might even have erased it entirely.

Sure, we all know the value of storing 3D printer filament under controlled conditions, to prevent the hygroscopic plastics from picking up atmospheric moisture. But [Sasa Karanovic] must really, REALLY hate the printing artifacts that result. Starting with a commercially available dry box that already had a built-in heating element, [Sasa] took it to the next level by replacing the controller and display with an ESP32. He added a fan to improve air circulation inside the enclosure and prevent stratification, as well as temperature and humidity sensors. Not satisfied with simply switching the heating element on and off at specific setpoints, he also implemented a PID loop to maintain a constant temperature. And of course, there’s a web UI and an API available for third-party control and monitoring.

The video below details [Sasa]’s design thoughts and goes into some detail on construction and performance. And while we may kid that this design is over-the-top, what really comes through is that this is a showcase for design ideas not only for one application, but for hardware projects in general. There are certainly simpler heated dry box designs, and zero-cost solutions as well, but sometimes going overboard has its own value too.

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IoT toilet paper sheet counter

Keep Track Of Toilet Paper Usage With This IoT Roll Holder

Remember the Great Toilet Paper Crisis of 2020? We sure do, and it looks like our old friend [Vije Miller] does as well, while seemingly harboring a somewhat morbid fascination about how much paper every bathroom visitor is consuming. And to that end, we present his IoT toilet sheet tracker.

His 3D printed roll holder has a Hall effect sensor that counts revolutions of the roll and sends it to a NodeMCU. The number of sheets per roll is entered when the roll is changed, so some simple math yields the number of sheets each yank consumes. Or at least a decent estimate — [Vije] admits that there’s some rounding necessary. The best part of the build is the connection to Thingspeak, where sheet usage is plotted and displayed. Go ahead and check it out if you dare; at the time of writing, there was an alarming spike in sheet usage — a sudden need for 68 sheets where the baseline usage is in single digits. We shudder to think what might have precipitated that. The video below is — well, let’s just say there’s a video.

This isn’t the first time we’ve seen bathroom-based projects from [Vije Miller]. A few years back there was an attempt to freshen the air with plasma, and his IoT shower valve controller probably never scalded anyone accidentally.

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WiFi bird box with phone showing video of a rubber ducky

Building A WiFi-Enabled Bird Box On The Cheap

[Jude] was looking for a fun DIY project for him and his son and thought that a bird box might be a good option. He wanted to equip the box with a WiFi camera so he could watch his little guests from his phone but didn’t find any suitable, inexpensive, commercially-available options. So with that, he built one himself.

He did, however, start with a generic bird box, which he bought online, and then modified with his particular features of interest. He wanted the project to be scalable so after-school programs and other kids clubs could easily implement his design within a classroom setting. He figured minimizing the woodwork would make the project easier for children.

He added a dowel to the generic bird box he bought online, but cautions that readers need to investigate if a dowel would attract invasive species in their area. He found a relatively inexpensive WiFi-enabled endoscope that he noted was far more affordable than the camera-equipped, commercially-available bird boxes he found earlier. He craftily used a plastic syringe as a waterproof spy hole that housed the endoscope, allowing him to easily slip the camera in and out of the bird box without disturbing its occupants. He noted that the 3 mL syringe had the perfect inner diameter to fit the endoscope rather snugly.

[Jude] doesn’t intend to have the endoscope active 24/7, so he needed a way to seal the access hole when the camera was not in use. His many years at Dyson taught him that implementing a removable, water-tight, rubber seal is not as easy as people may think. Fortunately, the rubber stopper at the tip of the syringe’s plunger was naturally a perfect removable seal and he could use it to plug the access hole when the endoscope was not in use.

The endoscope was mostly waterproof, except for the WiFi transmitter, so [Jude] needed to place that end of the device in a waterproof enclosure. He said these are often called “IP rated” enclosures and he figured these could come in handy for any number of outdoor electronics projects so we imagine this might come in handy for a lot of our readers as well.

Mother nature has certainly inspired many projects here at Hackaday and [Jude]’s bird box is no exception. Cool project!

The insides of a coffee machine replaced with new smart electronics

Add Smarts To Your Old Capsule Coffee Maker

Everyone has their preferred method of making (and consuming) coffee. While modern coffee makers are starting to come standard with IoT and ‘smart’ capabilities, owners of older models should fear not, as [Andreas Skoglund] shows how just about any old machine can be upgraded with the latest automation wizardry.

The most involved part of this conversion is removing the electronic guts of the Dolce Gusto donor machine, leaving just the original heater, pump and the control levers. With safety in mind, the user must make the machine ‘hot’ by configuring the levers and replacing the coffee capsule manually, otherwise no automated coffee magic can take place.

A low-tech relay powers on the coffee maker, with the entire logic supported by an off-the-shelf microcontroller. If you’re using a Particle.io controller, the provided instructions offer some helpful tips on automatically brewing your first beverage. From there it’s trivial to start using Home Assistant to set up various rules and schedules for your coffee drinking pleasure. You can even select whether you want a small or large cup.

There’s a few improvements that our coffee-starved hero suggests implementing, such as upgrading the power supply, as well as investing in refillable capsules to spite a certain global conglomerate corporation (plus it’s cheaper and much better for the environment). We’re not short on coffee-inspired hacks, so why not also check out this AI Powered Coffee Maker.

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Comfortable, wearable packaging for biometric device for monitoring physiological data and pushing the data to the cloud

A DIY Biometric Device With Some Security Considerations

Biohacking projects are not new to Hackaday and it’s certainly a genre that really piques our interest. Our latest biohacking device comes courtesy of [Manivannan] who brings his flavor of a wearable biosensor with some security elements built-in through AWS.

The hardware is composed of some impressive components we have seen. He has an AD8232 electrocardiogram front end, the MAX30102 integrated pulse oximeter IC for determining blood oxygen and heart rate, and the ever-popular LM35 for measuring body temperature. Either of these chips would be perfect for your next DIY biosensor project though you might try the MAX30205 body temperature sensor given its 0.1-degree Celsius accuracy. However, what really piqued our interest was the use of Microchip’s AVR-IoT WA Development Board. Now we’ve talked about this board before and also mentioned you could probably do all the same things with an ESP-device, but perhaps now we get to see the board a bit more in action.

[Manivannan] walks the reader through the board’s setup and everything looks to be pretty straightforward. He ultimately rigged together a very primitive dashboard for viewing all his vitals in real-time, demonstrating how you could put together your own patient dashboard for remote monitoring of vitals or other sensor signals. He emphasizes that all this is powered through AWS, giving him some added security layers that are critical for protecting his data from unwanted viewers.

Though [Manivannan’s] security implementation doesn’t rise to the standard of medical devices, maybe it will serve as a case study in the growing open-source medical device movement.

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