home hacks

1860 Articles

An E-Ink Progress Bar For Your Unborn Child

January 13, 2023 by 12 Comments

Having a child is a major milestone in a person’s life, and there’s a long list of things to get done before that little bundle of joy kicks and screams its way into the world. What better way to make sure you’ve still got time to paint the nursery and assemble the crib than to have an automated loading screen that shows just how far along the organic 3D printing process is?

This fetal development tracker was put together by [mokas] using Adafruit’s ESP32-S2 powered MagTag. As the name implies, the all-in-one electronic ink development board is designed so that it can be adhered to a metallic surface with integrated magnets. The idea is that you can pop a battery in the low-power device, stick it on your refrigerator, and have a regularly updated display of…well, whatever you want. Continue reading “An E-Ink Progress Bar For Your Unborn Child” →

Arduino Library Brings Rtl_433 To The ESP32

January 13, 2023 by 9 Comments

If you have an RTL-SDR compatible radio there’s an excellent chance you’ve heard of the rtl_433 project, which lets you receive and decode signals from an ever-expanding list of supported devices in the ISM radio bands. It’s an incredibly useful piece of software, but the fact that it requires an external software defined radio and a full-fledged computer to run dictated the sort of projects it could realistically be used for.

But thanks to the rtl_433_ESP Arduino library developed by [NorthernMan54], we’re now able to pack that functionality into a much smaller package. All you need is an ESP32 microcontroller and a CC1101 or SX127X transceiver module. If you’re looking for a turn-key hardware platform, the documentation notes the LILYGO LoRa32 V2 board includes the required hardware, plus adds a handy OLED display and microSD slot. It should be noted that the range of these radios don’t compare particularly well to a full-size RTL-SDR device, but that probably won’t come as much of a surprise. Continue reading “Arduino Library Brings Rtl_433 To The ESP32” →

Concrete Coffee Table Can Take A Beating

January 13, 2023 by 30 Comments

A good coffee table should have a hard-wearing surface and some serious heft to it. This build from [designcoyxe] hits both those criteria with its concrete-based design.

To create the table surface, the first step was to create a form. Melamine was used for the job, thanks to its smooth surface. A rectangular form was readily fabbed up, sealed internally and waxed, and then the concrete was poured. For added strength, the form was only half-filled, and a mesh was added for reinforcement. The rest of the concrete was then poured in to complete the tabletop. The table legs themselves were crafted out of maple, formerly used as a butcher’s block. The light wood makes a great contrast to the dark grey concrete. Plus, the stout, thick, wooden legs are a great combination with the strength of the tabletop itself.

It’s hard to overstate how good concrete is as a coffee table material. It’s difficult to damage and difficult to stain. Plus, if you really need to drive a point home, you can be certain slamming down your mug will get everyone’s attention (just be wary of injury). We’ve seen some other great concrete furniture before, too.

Continue reading “Concrete Coffee Table Can Take A Beating” →

An All-Billet, Single-Piece, Flexure-Based Nutcracker

January 11, 2023 by 22 Comments

Typical nutcrackers rely on simple pin hinges to join two handles for the cracking task. However, [adam the machinist] has demonstrated that a single-piece nutcracker is possible by using the flexural properties of the right grade of steel.

The nutcracker is manufactured out of 17-4 PH stainless steel, heat treated to the H900 condition. A flexural spring section at the top of the nutcracker takes the place of the usual hinge, allowing the handles to be squeezed together and the teeth of the cracker to open the nut. Machining the flexural section is first achieved with a series of CNC drill operations on the billet stock, before regular milling is used to shape the rest of the spring section and tool. The video dives deep into the finer points of the CNC operations that produce such a great finish on the final part. It even covers the use of a tiny scissor jack to help hold the handles still during machining.

The result is a highly attractive and desirable nutcracker that looks far more special than the regular fare you might pick up at Walgreens. The all-billet tool is a nutcracker very much fit for a sci-fi set. We’ve seen some other kitchen tools around here before, too, albeit of more questionable utility.

Continue reading “An All-Billet, Single-Piece, Flexure-Based Nutcracker” →

All Aboard The Garbage Express

January 2, 2023 by 39 Comments

Cog railways are a somewhat unusual way of train locomotion, typically only installed when a train needs to climb steep terrain. Any grade above about 10% needs the extra traction since the friction between the wheels and rails won’t be enough to push the train forward or keep it from falling backwards. Even without a steep hill to climb, sometimes a cog railway is necessary for traction as [Max Maker] discovered while building a train for his garbage cans.

The build started out as a way to avoid having to wheel his seven waste bins to the curb every month. Originally he built a more standard railway with a simple motor to drive the train, but he quickly realized that there wasn’t enough grip even when using plastic wheels, even though this track follows fairly flat terrain. Since the rail is built out of steel he quickly welded up a rack-and-pinion system to one of the rails. The build goes through many iterations before he finally settles on a design that solves the problem, and it includes several other features as well such as remote control and a spring-loaded automatic charger for the train at its station in the back yard.

While we always appreciate the eccentricity of those who would automate a relatively simple task that only happens once a month, [Max Maker] hopes to build this into a commercial product aimed at the elderly or disabled who would really benefit from a reliable, semi-automatic system that takes their trash bins to the curb for them. And, if your system only involves a single trash can, there are other ways of automating the task of taking the garbage to the curb.

Continue reading “All Aboard The Garbage Express” →

A simple wooden chair with mint metallic connectors at the corners sits next to a pile of wooden pieces wrapped in leather and straps to form a backpack.

A Nomadic Chair

December 29, 2022 by 21 Comments

There’s no shortage of different types of folding or portable chairs, but designer [Jorge Penadés] built a backpack chair that will go the long haul.

Furniture that assembles without screws or glue is always intriguing, and this chair fits the bill. Using simple metal connectors and joinery, it can be setup and taken down in about two minutes without the flimsy feeling of a bag chair. With a natural finish on the wood, the connectors give a nice pop of color without feeling overwhelming. There are even some pictures of a couch version if you follow the link.

In backpack mode, the pieces are held together by leather patches and ratchet straps. [Penadés] was focused on portability over comfort with this piece, but we think this connection method could be used in the future for more comfortable furniture that is still portable.

If you’re looking for more interesting furniture, checkout this Tambour Table with a Puzzling Secret or these CNC-able Seats.

Continue reading “A Nomadic Chair” →

Connecting Commercial 433 MHz Sensors To MQTT And Home Assistant With RTL-SDR

December 26, 2022 by 37 Comments

When [Elixir of Progress] was looking at setting up environmental sensors around their home to keep track of temperature, humidity and such, the obvious ideas of using WiFi-connected sensors didn’t work due to lack of WiFi range. Although Zigbee (Z-wave) sensors have longer range than WiFi, they are decidedly more expensive, proprietary and require a special transceiver hub. That’s where 433 MHz sensors for weather stations come into the picture.

The idea is simple: virtually all of those sensors – many of them rated for outdoor use – use the unlicensed 433 MHz spectrum that can easily be captured using cheap RTL-SDR (software defined radio) USB dongles. With the data stream from these sensors captured, the open source rtl_433 project enables automatic decoding of these data streams for a wide range of supported sensors.

While Realtek RTL2832-based and other RTL-SDRs can be found for quite cheap, it should be noted that these can run quite hot. Rather than heatsinking the IC, for this project it was elected to only listen sporadically and allow the RTL-SDR receiver to cool down in between listening sessions.

Getting the data from there into Home Assistant, InfluxDB or similar is easy, as rtl_433 can output the decoded data directly to an Influx database, MQTT broker as well as other formats. In this case, the data was sent via MQTT with the Home Assistant instance configured to treat these MQTT topics as sensors. With each sensor’s location carefully registered, this allows for setting up a dense, very low-power network of 433 MHz sensors for monitoring and home automation purposes.