KiwiSDR Vs RaspberrySDR — A Tale Of Two SDRs

Once you move away from the usual software defined radio (SDR) dongles, you have only a few choices unless you want to drop some serious cash. One common hobby-grade SDR is the KiwiSDR. This popular unit runs Linux and can receive up to 30 MHz. The platform uses a dedicated A/D converter, an FPGA, and BeagleBone computer. Success of course breeds imitators, and especially when you have an open source design like the Kiwi, you are going to find similar devices with possibly different end goals. That’s how the RaspberrySDR came to be. This is a very similar unit to the KiwiSDR but it uses a Raspberry Pi, along with a handful of other differences. What’s different? [KA7OEI] tells us in a recent blog post.

Other than the obvious difference of the computer and all that it entails, the RaspberrySDR has a higher speed A/D (125 MHz vs 66 MHz) and 16-bits of resolution instead of the Kiwi’s 14 bits. This combines to give the Raspberry a wider receive range (up to 60 MHz) and — in theory — better performance in terms of dynamic range and distortion.

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Displaying Incoming Server Attacks By Giving Server Logs A Scoreboard

In the server world, it’s a foregone conclusion that ports shouldn’t be exposed to the greater Internet if they don’t need to be. There are malicious bots everywhere that will try and randomly access anything connected to a network, and it’s best just to shut them off completely. If you have to have a port open, like 22 for SSH, it’ll need to be secured properly and monitored so that the administrator can keep track of it. Usually this is done in a system log and put to the side, but [Nick] wanted a more up-front reminder of just how many attempts were being made to log into his systems.

This build actively monitors attempts to log into his server on port 22 and notifies him via a numerical display and series of LEDs. It’s based on a Raspberry Pi Zero W housed in a 3D-printed case, and works by interfacing with a program called fail2ban running on the server. fail2ban‘s primary job is to block IP addresses that fail a certain number of login attempts on a server, but being FOSS it can be modified for situations like this. With some Python code running on the Pi, it is able to gather data fed to it from fail2ban and display it.

[Nick] was able to see immediate results too. Within 24 hours he saw 1633 login attempts on a server with normal login enabled, which was promptly shown on the display. A video of the counter in action is linked below. You don’t always need a secondary display if you need real-time information on your server, though. This Pi server has its own display built right in to its case.

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Into The Belly Of The Beast With Placemon

No, no, at first we thought it was a Pokemon too, but Placemon monitors your place, your home, your domicile. Instead of a purpose-built device, like a CO detector or a burglar alarm, this is a generalized monitor that streams data to a central processor where machine learning algorithms notify you if something is awry. In a way, it is like a guard dog who texts you if your place is unusually cold, on fire, unlawfully occupied, or underwater.

[anfractuosity] is trying to make a hacker-friendly version based on inspiration from a scientific paper about general-purpose sensing, which will have less expensive components but will lose accuracy. For example, the article suggests thermopile arrays, like low-resolution heat-vision, but Placemon will have a thermometer, which seems like a prudent starting place.

The PCB is ready to start collecting sound, temperature, humidity, barometric pressure, illumination, and passive IR then report that telemetry via an onboard ESP32 using Wifi. A box utilizing Tensorflow receives the data from any number of locations and is training to recognize a few everyday household events’ sensor signatures. Training starts with events that are easy to repeat, like kitchen sounds and appliance operations. From there, [anfractuosity] hopes that he will be versed enough to teach it new sounds, so if a pet gets added to the mix, it doesn’t assume there is an avalanche every time Fluffy needs to go to the bathroom.

We have another outstanding example of sensing household events without directly interfacing with an appliance, and bringing a sensor suite to your car might be up your alley.

TOBOT Is Your Tic Tac Toe Opponent With A Bad Attitude

[3dprintedlife] is apparently a little bored. Instead of whiling away the time playing tic tac toe, he built an impressive tic tac toe robot named TOBOT. The robot uses a Rasberry Pi Zero and a Feather to control a two-axis robot arm that can draw the board and make moves using a pen. It also uses a simple computer vision system to look at the board to understand your move, and it has a voice too.

The other thing TOBOT has is a bad attitude. The robot wants to win. Badly. Check out the video below and you’ll see what we mean.

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Cybercube Makes A Great Computing Companion

Oh, sure, there have been a few cube-shaped PCs over the years, like the G4 and the NeXT cube. But can they really be called cubes when the display and the inputs were all external? We think not.

[ikeji] doesn’t think so either, and has created a cube PC that puts them all to shame. Every input and output is within the cube, including our favorite part — the 48-key ortholinear keyboard, which covers two sides of the cube and must be typed on vertically. (If you’ve ever had wrist pain from typing, you’ll understand why anyone would want to do that.) You can see a gif of [ikeji] typing on it after the break.

Inside the 3D printed cube is a Raspberry Pi 4 and a 5″ LCD. There’s also an Arduino Pro Micro for the keyboard matrix, which is really two 4×6 matrices — one for each half. There’s a 6cm fan to keep things cool, and one panel is devoted to a grille for heat output. Another panel is devoted to vertically mounting the microcontrollers and extending the USB ports.

Don’t type on me or my son ever again.

When we first looked at this project, we thought the tiny cube was a companion macro pad that could be stored inside the main cube. It’s really a test cube for trying everything out, which we think is a great idea and does not preclude its use as a macro pad one of these days. [ikeji] already has plenty of plans for the future, like cassette support, an internal printer, and a battery, among other things. We can’t wait to see the next iteration.

We love a good cyberdeck around here, and it’s interesting to see all the things people are using them for. Here’s a cyberduck that quacks in Python and CircuitPython.

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Garbage Can Takes Itself Out

Home automation is a fine goal but typically remains confined to lights, blinds, and other things that are relatively stationary and/or electrical in nature. There is a challenge there to be certain, but to really step up your home automation game you’ll need to think outside the box. This automated garbage can that can take itself out, for example, has all the home automation street cred you’d ever need.

The garbage can moves itself by means of a scooter wheel which has a hub motor inside and is powered by a lithium battery, but the real genius of this project is the electronics controlling everything. A Raspberry Pi Zero W is at the center of the build which controls the motor via a driver board and also receives instructions on when to wheel the garbage can out to the curb from an Nvidia Jetson board. That board is needed because the creator, [Ahad Cove], didn’t want to be bothered to tell his garbage can to take itself out or even schedule it. He instead used machine learning to detect when the garbage truck was headed down the street and instruct the garbage can to roll itself out then.

The only other thing to tie this build together was to get the garage door to open automatically for the garbage can. Luckily, [Ahad]’s garage door opener was already equipped with WiFi and had an available app, unbeknownst to him, which made this a surprisingly easy part of the build. If you have a more rudimentary garage door opener, though, there are plenty of options available to get it on the internets.

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Tutorial For Setting Up Raspberry Pi For Ham Radio Use

There was a time when a ham radio set up sported many dials and switches and probably quite a few boxes as well. Computers have changed all that. Some transceivers now have just a few buttons or are even totally computer-controlled. Where a ham, at one time, might have a TeleType machine, a slow-scan TV monitor, and a fax printer for receiving satellite images, now that can all be on a single computer which can even be a Raspberry Pi. [F4GOH] has a post that takes you from the fundamentals to installing everything from an SDR to many common ham programs for digital modes, APRS, SSTV, and more. You can download the seven-part tutorial as separate PDF files, too.

Even if you aren’t a ham, you might find some of the software interesting. OpenWebRX lets you listen to your software defined radio on the road. You can use other software to pick up weather satellite data.

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