You Can Turn Soft Drink Bottles Into Handy Solar Lamps

March 29, 2022 by Lewin Day 17 Comments

Solar lights are a popular garden decoration. Of course, they’re available cheaply from most hardware and garden stores, but if you’re more of the DIY type, you might like to build your own. [opengreenenergy] has done just that, using recycled materials for a cheap and simple design.

The design was inspired by the Moser bottle, which is a water-filled bottle used to diffuse sunlight into a room during the day. Instead of sunlight, however, this design uses an LED to provide the light, for decorating a garden or for use when out camping or traveling.

In this design, a solar panel is used to charge a lithium-polymer battery during the day using a LP4060B5F charge controller IC. It’s paired with a AP6685 battery protection IC to ensure the battery is not overly discharged or otherwise damaged in use. When the solar panel stops putting out power when it gets dark, the LED is automatically switched on. It can be set to a low or high brightness to provide more runtime or more light as needed.

All the circuitry is wrapped up in a neat 3D-printed case that allows the hardware to be screwed directly on top of a regular soft drink bottle. Paired with some water in the bottle, and perhaps a little bleach to stave off algal growth, the result is a handy, portable light that also has enough mass to avoid it being blown over easily.

It’s interesting to compare the design to commercial versions that aim to pare costs down to a minimum. Video after the break.

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Custom Controller Ups Heat Pump Efficiency

March 25, 2022 by Bryan Cockfield 59 Comments

Heat Pumps are an extremely efficient way to maintain climate control in a building. Unlike traditional air conditioners, heat pumps can also effectively work in reverse to warm a home in winter as well as cool it in summer; with up to five times the efficiency of energy use as a traditional electric heater. Even with those tremendous gains in performance, there are still some ways to improve on them as [Martin] shows us with some modifications he made to his heat pump system.

This specific heat pump is being employed not for climate control but for water heating, which sees similar improvements in efficiency over a standard water heater. The problem with [Martin]’s was that even then it was simply running much too often. After sleuthing the energy losses and trying a number of things including a one-way valve on the heating water plumbing to prevent siphoning, he eventually found that the heat pump was ramping up to maximum temperature once per day even if the water tank was already hot. By building a custom master controller for the heat pump which includes some timing relays, the heat pump only runs up to its maximum temperature once per week.

While there are some concerns with Legionnaire’s bacteria if the system is not maintained properly, this modification still meets all of Australia’s stringent building code requirements. His build is more of an investigative journey into a more complex piece of machinery, and his efforts net him a max energy usage of around 1 kWh per day which is 50% more efficient than it was when it was first installed. If you’re looking to investigate more into heat pumps, take a look at this DIY Arduino-controlled mini heat pump.

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Sensor Playground Keeps Track Of Indoor Air Quality Through The Cloud

March 19, 2022 by Robin Kearey 8 Comments

When [tdw] wasn’t feeling well one day, his wife suggested that it might be due to poor air quality in their home. While an ordinary person could have simply opened a window after hearing such an idea, [tdw] instead showed his true hacker spirit and set about measuring the indoor air quality. He began by designing a simple PCB to measure CO2 and volatile organic compound (VOC) levels, but eventually broadened his scope to end up with the Sensor Playground: a plug-and-play platform to read out various sensors and store the results in the cloud.

Deliberately designed to be easy to assemble with minimal soldering skills, the Sensor Playground consists of a big two-layer PCB onto which various modules can be plugged. It supports either an ESP32 DevKit or an Adafruit Feather module to provide processing power, and provides sockets for a bunch of sensors, conveniently wired with power and SPI or I2C. It also provides a rotary encoder and two buttons for user input. All source files are available on [tdw]’s GitHub page, ready to be applied to any kind of sensing task.

[tdw] set up his Sensor Playground with sensors measuring CO2, VOC, PM2.5 (particulate matter), as well as temperature and relative humidity. A web interface allows anyone to track these measurements in real-time. The open and modular design should make it easy to extend this system with various other sensor types: we can imagine that things like solar irradiation, outside temperature and wind speed would also add useful data to the mix. Perhaps even a Geiger counter to keep track of radiation levels?

As indoor air quality sensors go, this one is definitely comprehensive and easy to use. We’ve featured other air quality sensors before, some of which also link their data to the cloud.

Three flowers in a corner of a darkened room, shining in different colors.

LED Flower Bouquet Is A Radiant Hacker Desk Decoration

March 15, 2022 by Arya Voronova 4 Comments

[Jeremy Cook] writes to us about a project of his – a bouquet of LED cube flowers. The flowers are PCB cubes made out of small castellated PCBs, each of those having an individually addressable LED in its center. Castellations hold the cubes together mechanically, and thanks to a cleverly chosen pinout, only two different kinds of PCB need to be ordered for building such a flower!

As a vase for these flowers, he decided to use a glass bottle – which would need a cutout to fit a ESP8266-powered NodeMCU board, a controller of choice for the project. After a few different approaches for cutting glass all resulted in the bottles cracking, he gave up on the “clean cut” idea and reused one of the broken bottles, gluing it back together well enough for the aesthetic to work.

[Jeremy] tells us that he’s had help from a hack we covered back in 2017 – using a diode for level shifting, as the ESP8266’s 3.3 V level signals aren’t a good match for WS2812 inputs. From there, the WLED firmware for the ESP8266 ties everything together beautifully. It’s clear that [Jeremy] had a field day designing this, toying with all the ideas and approaches!

Colorful LEDs are a must-have for decorating hacker homes. From a bouquet of flowers, you might find yourself sketching a castellated PCB tile design, and next thing you know, you’ve created a beautiful system of LED triangle tiles. Some PCB fabs scoff at castellations, and if that’s the case, you might as well finish the job yourself.

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Reversible Ventilation Hack Keeps The Landlord Happy

March 13, 2022 by Ryan Flowers 26 Comments

When a person owns the home they live in, often the only approval they need for modifications is from their significant other or roommate. In the worst case, maybe a permit is required. But those who rent their dwellings are far more constrained in almost every case, and when it comes to environmental controls, they are most decidedly off limits. Unless you’re a resourceful hacker like [Nik], that is, who has seamlessly integrated his apartment’s ventilation system into his smart home controller — all without any permanent modifications!

The controller itself only gives three settings to vent the apartment: Low, Medium, High, and then High for 30 minutes, with all modes having to be actuated with a manual button press. [Nik] wanted automation and integration with his smart home.

A clean 3D printed enclosure wraps things nicely

Thankfully, the engineers who designed the controller used in [Nik]’s apartment made it very convenient to reverse engineer it. A flat ribbon cable conveniently breaks out all of the buttons and 12 VDC, and he can interface directly using its connector. First hack: done.

Next, [Nik] needed a longer cable to run between the controller and his ESP8266 based control module. Finding the connector on AliExpress was easy, but finding a compatible cable of length required some more resourcefulness. The cable was eventually sourced from the airbag controller of a Renault Megane! Second hack, using a car part in a controller: well done!

Integration into his smart home wasn’t just electronic. The module looks right at home above the original controller, and if you didn’t know better you’d never think it wasn’t original equipment. Final hack: Done!

Be sure to check out his build log over at Hackaday.io, and if home automation hacks are your cup of tea, check out this automatic tea maker.

Build Yourself A Weather-Reporting Diorama

March 12, 2022 by Lewin Day 1 Comment

These days, if you don’t fancy watching morning TV, you can always get an update on the day’s weather from your smartphone, computer, or any one of a series of other connected devices. However, if you’re looking for a more fun way to see what’s in store, this weather diorama from [Lewis] of DIY Machines might be just what you’re looking for.

The build uses an ESP32 as the brains of the project, responsible for querying the Internet for up-to-date weather information. This info is then displayed on a 2.9″ e-ink display, showing the temperature, chance of rain, and wind speed predicted for the local area. So far, so straightforward.

However, where it gets really creative is the use of laser-cut “scene discs” with different graphics on them to represent different weather conditions. They can alternatively be 3D printed,too. These are rotated via servos controlled by the ESP32, allowing the diorama to display a representative scene informed by the current forecast. If there’s snow coming, you’ll see a snow man, but if things are looking fine, you’re more likely to see a woman strolling with a dog.

It’s a fun way to learn about what Mother Nature has in store, and would look great on any breakfast bar to boot. We’ve seen some great builds from [Lewis] before, too, like this amazing seven-segment clock shelf.

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

February 24, 2022 by Robin Kearey 37 Comments

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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