Author: John Elliot V

81 Articles

A diagram with one Tag and two Base Stations.

Using Ultra-Wideband For 3D Location And Tracking

August 19, 2025 by 9 Comments

Interested in playing with ultra-wideband (UWB)? [Jaryd] recently put together a fairly comprehensive getting started guide featuring the AI Thinker BU03 that looks like a great place to start. These modules can be used to determine distance between two of them to an accuracy in the order of 10 centimeters, and they can do so in any orientation and with obstacles in the line of sight. It is possible to create a network of these UWB modules to get multiple distance measurements at once and enable real-time 3D tracking for your project.

[Jaryd] gathers up nine UWB modules and uses a Raspberry Pi Pico for command and control purposes. He explains how to nominate the “tag” (the device being tracked) and the “base stations” (which help in locating the tag). He reports having success at distances of up to about 10 meters and in favorable circumstances all the way up to as much as 30 meters.

If you don’t know anything about UWB and would like a primer on the technology be sure to check out What Is Ultra Wideband?

Three stages of the dam construction

How To Convert A Drain Into A Hydropower Facility

August 16, 2025 by 32 Comments

Over on his YouTube channel [Construction General] shows us how to convert a drain into a hydropower facility. This type of hydroelectric facility is known as a gravitation water vortex power plant. The central structure is a round basin which includes a central drain. The water feeds into the basin through a series of pipes which help to create the vortex which drives the water turbine before flowing out the drain.

To make the facility [Construction General] starts by laying some slabs as the foundation. One of the slabs has a hole to which the central drain pipe is attached. Bricks and mortar are then used to build the basin around the drain. A temporary central pipe is used for scaffolding along with some strings with hooks attached to hold the bricks and mortar in place for the basin. Integrated into the top half of the basin are fifteen inlet pipes which feed in water at an angle.

The next step is to build the dam wall. This is a bricks and mortar affair which includes the drain in the bottom of the wall and two spillways at the top. The spillways are for letting water flow out of the dam if it gets too full. Around the drainage in the dam wall a valve is installed. This valve is called the low-level outlet or the bottom outlet, and in this case it is a sluice, also known as a slide gate, which can be raised or lowered to control the rate of flow through the turbine.

Once the basin is complete and the low-level outlet is in place the scaffolding is removed. The basin is then painted, pink on the inside and white around the top. A turbine is constructed from various metal pieces and installed into the basin. The turbine is attached to a generator which is fixed atop the basin. The apparatus for operating the low-level outlet is installed and the dam is left to fill.

Hydropower is a topic we’ve covered here at Hackaday before, if you’re interested in the topic you might like to check out A Modest But Well-Assembled Home Hydropower Setup, Hydropower From A Washing Mashine, or Bicycle Hub Hydropower.

Continue reading “How To Convert A Drain Into A Hydropower Facility” →

A before and after with the plank of wood shown and the resulting chair also shown.

Liberating A Collapsible Chair From A Single Piece Of Wood

August 15, 2025 by 11 Comments

Over on his YouTube channel our hacker [GrandpaAmu] liberates a collapsible chair from a single piece of wood.

With the assistance of an extra pair of hands, but without any power tools in sight, this old master marks up a piece of wood and then cuts a collapsible chair out of it. He uses various types of saw, chisels, a manual drill, and various other hand tools. His workspace is a humble plank with a large clamp attached. At the end he does use a powered hot air gun to heat the finish he uses to coat the final product.

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A photo of a the power supply, distribution board, and primary and secondary windings on a bench top.

Bench-Top Wireless Power Transmission

August 14, 2025 by 8 Comments

[mircemk] has been working on wireless power transmission. Using a Class-E Tesla coil with 12 turns on the primary and 8 turns on the secondary and a 12 volt input he can send a few milliwatts to power an LED over a distance of more than 40 centimeters or power a 10 watt bulb over a distance of about 10 centimeters. With the DC input set at 24 volts the apparatus can deliver 5 watts over a distance of a few centimeters and a light is still visible after separating the primary and secondary coils by more than 30 centimeters.

There are many types of Tesla coil and we can’t go into the details here but they include Spark-Gap Tesla Coils (SGTC) and Solid-State Tesla Coils (SSTC), among others. The Class-E coil demonstrated in this project is a type of SSTC which in general is more efficient than an SGTC alternative.

Please bear in mind that while it is perfectly safe to watch a YouTube video of a person demonstrating a functional Tesla coil, building your own is hazardous and probably not a good idea unless you really understand what you’re doing! Particularly high voltages can be involved and EMI/RFI emissions can violate regulations. You can damage your body with RF burns while not feeling any pain, and without even knowing that it’s happening.

If you’d like to read more about wireless power transmission it is certainly a topic we’ve covered here at Hackaday in the past, you might like to check out Wireless Power Makes For Cable-Free Desk or Transmitting Wireless Power Over Longer Distances.

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A photo of the circuit board with components soldered on

A Solar-Only, Battery-Free Device That Harvests Energy From A BPW34 Photodiode

August 10, 2025 by 21 Comments

Normally when you think solar projects, you think of big photovoltaic cells. But a photodiode is just an inefficient, and usually much smaller, PV cell. Since [Pocket Concepts]’s Solar_nRF has such a low power budget, it can get away with using BPW34 photodiodes in place of batteries. (Video, embedded below.)

The BPW34 silicon PIN photodiode feeds a small voltage into a BQ25504 ultra-low-power boost converter energy harvester which stores power in a capacitor. When the capacitor is fully charged the battery-good pin is toggled which drives a MOSFET that powers everything downstream.

When it’s powered on, the Nordic nRF initializes, reads the current temperature from an attached I2C thermometer, and then sends out a Bluetooth Low Energy (BLE) advertising packet containing the temperature data. When the capacitor runs out of energy, the battery-good pin is turned off and downstream electronics become unpowered and the cycle begins again.

Continue reading “A Solar-Only, Battery-Free Device That Harvests Energy From A BPW34 Photodiode” →

A photo of the PDP-1 replica.

Hacking Printed Circuit Board To Create Casing And Instrument Panels

August 9, 2025 by 11 Comments

Over on Hackaday.io our hackers [Angelo] and [Oscarv] are making a replica of the PDP-1. That is interesting in and of itself but the particularly remarkable feature of this project is its novel use of printed circuit boards for casing and instrument panels.

What does that mean in practice? It means creating a KiCad file with a PCB for each side of the case/panel. These pieces can then be ordered from a board house and assembled. In the video below the break you will see an example of putting such a case together. They use sticky tape for scaffolding and then finish things off by soldering the solder joints on each edge together.

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A man standing next to a host of small automatic trash cans

Automated Rubbish Removal System

August 6, 2025 by 15 Comments

The hackers over at [HTX Studio] built a set of twenty trash cans which can automatically catch and remove rubbish.

In order to catch trash a bin needs to do two things: detect where trash will land; and then get there, fast. The second part is easy: three big motors with wheels under the bin. But how does a bin know where the trash will land? It uses a camera installed in the bin itself for that.

[HTX Studio] iteratively trained a model to process visual information from the camera to identify common types of trash. When it sees a trained object flying through the air it rushes to catch it where it will land. After many rounds of fine-tuning it finally started to work reliably.

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