RTL-SDR is a very cheap ~$25 USB dongle that can be used as a computer based radio scanner for receiving live radio signals in your area (no internet required). Depending on the particular model it could receive frequencies from 500 kHz up to 1.75 GHz. Most software for the RTL-SDR is also community developed, and provided free of charge.
The origins of RTL-SDR stem from mass produced DVB-T TV tuner dongles that were based on the RTL2832U chipset. With the combined efforts of Antti Palosaari, Eric Fry and Osmocom (in particular Steve Markgraf) it was found that the raw I/Q data on the RTL2832U chipset could be accessed directly, which allowed the DVB-T TV tuner to be converted into a wideband software defined radio via a custom software driver developed by Steve Markgraf. If you’ve ever enjoyed the RTL-SDR project please consider donating to Osmocom via Open Collective as they are the ones who developed the drivers and brought RTL-SDR to life.
For years now Google Maps did not allow us to download Offline Maps for Japan. It is an extremely useful feature when you are out and about and you might not yet have full mobile coverage or your plan is not set-up yet.
A week ago this was not possible and I have just now noticed that you can now select the Japan area for a custom offline map in the Google Maps app on my iPhone and on my iPad.
This is great news! Do you use the offline map feature?
This application generates a random medieval city layout of a requested size. The generation method is rather arbitrary, the goal is to produce a nice looking map, not an accurate model of a city. Maybe in the future I’ll use its code as a basis for some game or maybe not.
“Shepard’s Pi” is one continous song that lasts for 999,999,999 hours, or about 114 years.
Canton Becker’s music generating algorithm composed this music using the first one billion digits of pi (p). Each digit (3.1415…) determines four seconds of music, supplying the “turn signals” used to determine every musical expression.
Because the numbers in pi never repeat, each of the million hours of “Shepard’s Pi” music are in fact unique. By fast forwarding to some distant moment in the song, you are virtually guaranteed to find yourself listening to something that nobody else including Canton himself has ever heard before.
Apparently my choice of purchasing the HD-DVD drive for the Xbox 360 will ultimately pay off!! As we all know Bluray won that format war back in the days.
But now it seems that this below would be useable for something:
Over the life of nuclear fuel, inhomogeneous structures develop, negatively impacting thermal properties. New fuels are under development, but require more accurate knowledge of how the properties change to model performance and determine safe operational conditions.
Measurement systems capable of small–scale, pointwise thermal property measurements and low cost are necessary to measure these properties and integrate into hot cells where electronics are likely to fail during fuel investigation. This project develops a cheaper, smaller, and easily replaceable Fluorescent Scanning Thermal Microscope (FSTM) using the blue laser and focusing circuitry from an Xbox HD-DVD player.
Streamsheets is, similar to NodeRed, a tool to step in between MQTT data coming in and something being done with it. Just other than NodeRed it is not based on flows but on a spreadsheet that executes in it’s entirety everytime a step is made.
Streamsheets are a new spreadsheet technology specifically designed for real-time data stream processing and the opportunities of digitization and the Industrial IoT.
Unlike some other efforts this doesn’t just render SwiftUI Views as HTML. It also sets up a connection between the browser and the code hosted in the Swift server, allowing for interaction – buttons, pickers, steppers, lists, navigation, you get it all!
In other words: SwiftWebUI is an implementation of (many but not all parts of) the SwiftUI API for the browser.
To repeat the Disclaimer: This is a toy project! Do not use for production. Use it to learn more about SwiftUI and its inner workings.
As RISC-V progressively challenges the existing ARM processor ecosystem it’s interesting to see more and more software projects popping up that aim that RISC-V architecture.
Here’s one project that aims to develop (and explain along the way) how to create an operating system from scratch. On top of the RISC-V specifics this tutorial also aims to teach how this all can be done in a programming language called Rust.
Keep in mind that all of this is done on a baremetal system. No other software is running.
RISC-V (“risk five”) and the Rust programming language both start with an R, so naturally they fit together. In this blog, we will write an operating system targeting the RISC-V architecture in Rust (mostly). If you have a sane development environment for RISC-V, you can skip the setup parts right to bootloading. Otherwise, it’ll be fairly difficult to get started.
This tutorial will progressively build an operating system from start to something that you can show your friends or parents — if they’re significantly young enough. Since I’m rather new at this I decided to make it a “feature” that each blog post will mature as time goes on. More details will be added and some will be clarified. I look forward to hearing from you!
Can you display VGA and play audio on a Cortex-M4 in pure Rust? The short answer is yes, yes you can! Minus the hand-unrolled assembler loop for fixing the phase error in the RGB output. But we don’t talk about that in polite company.
The Atari Joystick interface works, but two Joysticks would be more fun
The PS/2 Keyboard via the Atmega works, but the pinout was mirrored so you have to put the connector under the PCB :/
The RTC works
VGA Output works
The MIDI Out seems to work when looped to MIDI In, as does the MIDI Though.
The MIDI In seems to receive data when connected to my electronic drum kit
The Audio output seems to work quite nicely
The SD card works, but the power supply can’t handle hot-insertion of the SD card and it makes the TM4C reboot. More capacitors / some current limiting probably required.
I can load games and programs from the SD card into the 24 KiB of free Application RAM. You can interact with these games via the PS/2 Keyboard and Joystick. I can play simple games (like Snake) and play three channels of 8-bit wavetable audio simultaneously. I’ve even got a 6502 Emulator running a copy of 6502 Enhanced BASIC, if you want to go old school!
As you might know I am regularly looking into indoor-location systems and opportunities to optimize my own system (based on Bluetooth…)
Now I cam across a concept by a german company called Localino. They’ve built their own hard- and software.
Localino has its own “satellites”, also called “anchors”. The mobile receivers are called “tags” and can locate their position based on the available anchors inside a building. Anchors and tags precisely measure signal propagation delays in the order of sub-nanoseconds, resulting in centimeter-accurate location. Any person or object wearing a tag can be located.
I am back again and developing some smaller APIs for my own use.
As I am learning a new programming language and framework (SwiftUI) and for my little learning project I need to also implement a server backend. Implementing a RESTful service is quite straight-forward but for testing and UI prototyping I actually want to do some testing before really setting up the server side.
To easily test RESTful calls without actually implementing anything I found that Reqres is a quite useful tool to have in the toolbelt:
Apart from some pre-set-up API endpoints with dummy data (like users, …) it also features a request mirror service.
With that you can simply throw a JSON document into the general direction of Reqres and it will put a timestamp on it and return it right away.
User space network drivers on Linux are often used in production environments to improve the performance of network-heavy applications. However, their inner workings are not clear to most programmers who use them. ixy aims to change this by providing a small educational user space network driver, which is gives a good overview of how these drivers work, using only 1000 lines of C code. While the language C is a good common denominator, which many developers are familiar with, its syntax is often much more dicult to read than that of more modern languages and makes the driver seem more complex than it actually is.
For this thesis I created a C# version of ixy, named ixy.cs, which utilizes the more modern syntax and additional safety of the C# programming language in order to make user space network driver development even more accessible. The viability of C# for driver programming will be analyzed and its advantages and disadvantages will be discussed.
The actual implementation (with other programming languages as well) can be found here.