Haptick: The Strain Gauge Based 6DoF Controller

March 20, 2023 by 16 Comments

Six degrees of freedom (6DoF) controllers are used for manipulating an object in a CAD or 3d modeling program and are often called spacemice. You can twist it, push it, and even bop it. Most work with optical encoders, shining an LED through a slit to some form of photodetector on the other side. [Matthew Schubert] wanted to make his own spacemouse, but had some new ideas of how to go about it. His two-part project, dubbed haptic, focuses on measuring the forces, not the displacement.

He decided to try thick-film resistors as strain gauges and revisit load cells and proper strain gauges later. The actual structure quickly converged on the Stewart Platform, formed from three custom PCBs. A base to sit on, a knob for the top, and a middle board designed to take the strain with SMD resistors. A Teensy 3.2 talks to the ADS131M06 ADC and streams 4k samples per second to the host computer via serial. For prototyping, the calculations were done on the PC. Continue reading “Haptick: The Strain Gauge Based 6DoF Controller” →

The Rise And (Eventual) Fall Of The SIM Card

March 20, 2023 by 109 Comments

There are few devices that better exemplify the breakneck pace of modern technical advancement than the mobile phone. In the span of just a decade, we went from flip phones and polyphonic ringtones to full-fledged mobile computers with quad-core processors and gigabytes of memory.

While rapid advancements in computational power are of course nothing new, the evolution of mobile devices is something altogether different. The Razr V3 of 2003 and the Nexus 5 of 2013 are so vastly different that it’s hard to reconcile the fact they were (at least ostensibly) designed to serve the same purpose — with everything from their basic physical layout to the way the user interacts with them having undergone dramatic changes in the intervening years. Even the network technology they use to facilitate voice and data communication are different.

Two phones, a decade apart.

Yet, there’s at least one component they share: the lowly SIM card. In fact, if you don’t mind trimming a bit of unnecessary plastic away, you could pull the SIM out of the Razr and slap it into the Nexus 5 without a problem. It doesn’t matter that the latter phone wasn’t even a twinkling in Google’s eye when the card was made, the nature of the SIM card means compatibility is a given.

Indeed there’s every reason to believe that very same card, now 20 years old, could be installed in any number of phones on the market today. Although, once again, some minor surgery would be required to pare it down to size.

Such is the beauty of the SIM, or Subscriber Identity Module. It allows you to easily transfer your cellular service from one phone to another, with little regard to the age or manufacturer of the device, and generally without even having to inform your carrier of the swap. It’s a simple concept that has served us well for almost as long as cellular telephones have existed, and separates the phone from the phone contract.

So naturally, there’s mounting pressure in the industry to screw it up.

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Remote Water Quality Monitoring

March 20, 2023 by 8 Comments

While it can be straightforward to distill water to high purity, this is rarely the best method for producing water for useful purposes. Even drinking water typically needs certain minerals in it, plants may need a certain pH, and wastewater systems have a whole host of other qualities that need to be measured. Measuring water quality is a surprisingly complex endeavor as a result and often involves a wide array of sensors, much like this water quality meter from [RowlesGroupResearch].

The water quality meters that they are putting to use are typically set up in remote locations, without power, and are targeting natural bodies of water and also wastewater treatment plants. Temperature and pH are simple enough to measure and grasp, but this device also includes sensors for total dissolved solids (TDS) and turbidity which are both methods for measuring various amounts and types of particles suspended in the water. The build is based around an Arduino so that it is easy for others to replicate, and is housed in a waterproof box with a large battery, and includes data logging to an SD card in order to make it easy to deploy in remote, outdoor settings and to gather the data at a later time.

The build log for this device also goes into detail about all of the steps needed to set this up from scratch, as well as a comprehensive bill of materials. This could be useful in plenty of professional settings such as community wastewater treatment facilities but also in situations where it’s believed that industrial activity may be impacting a natural body of water. For a water quality meter more focused on drinking water, though, we’d recommend this build that is trained on its own neural network.

A Feature-Rich Amplifier Module For 3-Way Speaker Builds

March 20, 2023 by 22 Comments

There’s something rewarding about building your own DIY audio hardware. Knowing you put it together yourself gives you faith in the construction, and psychosomatically makes the music sound all that much sweeter. If you’re into that kind of thing, you might like to give [Eric Sorensen’s] Denmark amplifier module a look.

The amplifier is intended to be used in a 3-way system, running a subwoofer, woofer, and tweeter. It uses a 1000 W ICEpower module to run the subwoofer, with a pair of 500W ICEpower modules to run the woofer and tweeter respectively. Meanwhile, a MiniDSP 2x4HD is used to accept optical audio input. It also offers digital signal processing and serves as a crossover to split the signal across the three speakers. An STM32F401 is used to run the show, controlling all the various modules and the necessary status LEDs. It’s a feature-rich build, too, with overtemperature monitoring, fan control, and clipping warnings built in.

The whole setup is built on to a sturdy aluminium backplate. The CNC-machined panel has simple tactile buttons for control. There’s also a nifty use of clear PETG 3D printer filament as a light pipe for LEDs. It’s effective, and it looks great. The whole module is designed to slide into the bottom of a 3-way speaker housing like a drawer.

Overall, if you’re building a big set of 3-way speakers, you might find the Denmark amplifier module is perfect for your needs. Alternatively, you could experiment with a different kind of speaker entirely. Video after the break.

Continue reading “A Feature-Rich Amplifier Module For 3-Way Speaker Builds” →

A Pi Pico soldered onto a custom breakout PCB, with an SD card connected to it using prototyping wires

RP2040 Runs Linux Through RISC-V Emulation

March 19, 2023 by 27 Comments

We’re used to running Linux on CPUs where it belongs, and the consensus is that RP2040 just isn’t up for the task – no memory controller, and nowhere near enough RAM, to boot. At least, that’s what you might believe until you see [tvlad1234]’s Linux-on-RP2040 project, reminding us there’s more than one way to boot Linux on a CPU like this! Just like with the “Linux on AVR” project in 2012 that emulated an ARM processor, the pico-rv32ima project emulates a RISC-V core – keeping up with the times.

Initially, the aforementioned “Linux on AVR through ARM” project was picked as a base – then, a newer development, [cnlohr]’s RISC-V emulator, presented itself and was too good to pass up on. Lack of RAM was fully negated by adding an SD card into the equation – coupled with a small caching layer, this is a crucial part for the project’s not-so-secret sauce. A fair amount of debugging and optimization later, [tvlad1234] got Linux to run, achieving boot times in 10-15 minutes’ ballpark – considering the emulation layer’s presence, this is no mean feat.

At this point, the boot process stalls as you enter a login shell. If Linux on RP2040 is within your area of interest, feel free to pick up the effort from here, as the project is fully open-source – you only need a Pi Pico board and a throwaway SD card! Now, if pairing a RP2040 with some classic software is your definition of an evening well-spent, you can’t go wrong with DOOM! However, if you’d rather play with something else *nix-like, we’ve seen someone port Fuzix onto the RP2040 before.

A Look At Zweikanalton Stereo Audio And Comparison With NICAM

March 19, 2023 by 1 Comment

With how we take stereo sound for granted, there was a very long period where broadcast audio and television with accompanying audio track were in mono. Over the decades, multiple standards were developed that provide a way to transmit and receive two mono tracks, as a proper stereo transmission. In a recent video, [Matt] over at [Matt’s Tech Barn] takes a look at the German Zweikanalton (also known as A2 Stereo) standard, and compares it with the NICAM standard that was used elsewhere in the world.

Zweikanalton is quite simple compared to NICAM (which we covered previously), being purely analog with a second channel transmitted alongside the first. Since it didn’t really make much of a splash outside of the German-speaking countries, equipment for it is more limited. In this video [Matt] looks at the Philips PM 5588 and Rohde & Schwarz 392, analyzing the different modulations for FM, Zweikanalton and NICAM transmissions and the basic operation of the modulator and demodulator equipment.

An interesting aspect of these modulations are the visible sidebands, and the detection of which modulation is used. Ultimately NICAM’s only disadvantage compared to Zweikanalton was the higher cost of the hardware, but with increased technological development single-chip NICAM solutions like the Philips SAA7283 (1995) began to reduce total system cost and by the early 2000s NICAM was a standard feature of TV chipsets, just in time for analog broadcast television to essentially become irrelevant.

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Hackaday Links: March 19, 2023

March 19, 2023 by 11 Comments

We get results! Well, sort of. You may recall that in this space last week we discussed Ford’s plans to exclude AM reception on the infotainment systems of certain of their cars starting in 2024. We decried the decision, not for the loss of the sweet, sweet content that AM stations tend to carry — although we always enjoyed “Traffic on the 8s” back in our dismal days of daily commuting — but rather as a safety concern, because AM radio can reach almost the entire US population with emergency information using just 75 stations. To our way of thinking, this makes AM radio critical infrastructure, and eliminating it from motor vehicles is likely to have unintended consequences. Now it seems like there’s some agreement with that position, as former administrators of FEMA (Federal Emergency Management Administration; and no, not FEDRA) have gotten together to warn about the dangers of deleting AM from cars. Manufacturers seem to be leaning into the excuse that EVs emit a lot of radio frequency interference, rendering static-sensitive AM receivers less useful than other, more profitable less susceptible modes, like digital satellite radio. That seems like a red herring to us, but then again, the most advanced infotainment option in any car we’ve ever owned is a CD player, so it’s hard for us to judge.

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