The $50 Ham: Checking Out The Local Repeater Scene

So far in this series, we’ve covered the absolute basics of getting on the air as a radio amateur – getting licensed, and getting a transceiver. Both have been very low-cost exercises, at least in terms of wallet impact. Passing the test is only a matter of spending the time to study and perhaps shelling out a nominal fee, and a handy-talkie transceiver for the 2-meter and 70-centimeter ham bands can be had for well under $50. If you’re playing along at home, you haven’t really invested much yet.

The total won’t go up much this week, if at all. This time we’re going to talk about what to actually do with your new privileges. The first step for most Technician-class amateur radio operators is checking out the local repeaters, most of which are set up exactly for the bands that Techs have access to. We’ll cover what exactly repeaters are, what they’re used for, and how to go about keying up for the first time to talk to your fellow hams.

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Monitor Foot Traffic Using Radio

We talk a lot about information security around here, but in reality it’s not at the forefront of everyone’s minds. Most people are content to walk around with their phones constantly looking for WiFi or Bluetooth connections despite the dangers. But if you’re not a black hat sort of person, you can do something like [Verkehrsrot] did and use all of these phones to do something useful and harmless.

[Verkehrsrot]’s project involves building a radio listening device in order to get an estimate of the amount of traffic in a particular area. The device polls for and detects WiFi and Bluetooth devices nearby and tallies them. For the privacy-minded, it doesn’t persistently store any information about the people or the devices that it detects. The project also runs on a variety of platforms, although you can get the whole thing up and running with little more than an ESP32 and a small lithium-ion battery.

If you’re looking for a useful way to tally the number of people in a given area, this project could be the thing for you. Not everyone keeps their WiFi and Bluetooth turned on, but even so this is still a good way to estimate. But if you need to count everyone going into a room, for example, you’ll need another way to count them.

Trainspotting With Junk, For Science

[Douglas] hometown Goshen, Indiana takes the state’s motto ‘The Crossroads of America’ seriously, at least when it comes to trains. The city is the meeting point of three heavily frequented railroad tracks that cross near the center of town, resulting in a car-traffic nightmare. When everybody agrees that a situation is bad, it is time to quantify exactly how bad it is. [Douglas] stepped up for this task and delivered.

High tech train counting equipment

He describes himself as cheap, and the gear he used to analyze the railroad traffic at a crossing visible from his home certainly fits the bill: a decades-old webcam, a scratched telephoto lens and a laptop with a damaged hinge.

With the hardware in place, the next step was to write the software to count and time passing trains. Doing this in stable conditions with reasonable equipment would pose no problem to any modern image processing library, but challenged with variable lighting and poor image quality, [Douglas] needed another solution.

Instead of looking for actual trains, [Douglas] decided to watch the crossing signals. His program crops the webcam image and then compares the average brightness of the left and right halves to detect blinking. This rudimentary solution is robust enough to handle low light conditions as well as morning glare and passing cars.

The rest is verifying the data, making it fit for processing, and then combining it with publicly available data on car traffic at the affected intersections to estimate impact. The next council meeting will find [Douglas] well prepared. Traffic issues are a great field for citizen science as shown in Stuttgart earlier. If the idea of bolting old lenses to webcams intrigues you, we got you covered as well.

Dedicated Automobile Traffic Monitor With Raspberry Pi

[j3tstream] wanted an easier way to monitor traffic on the roads in his area. Specifically, he wanted to monitor the roads from his car while driving. That meant it needed to be easy to use, and not too distracting.

[j3tstream] figured he could use a Raspberry Pi to run the system. This would make things easy since he’d have a full Linux system at his disposal. The Pi is relatively low power, so it’s run from a car cigarette lighter adapter. [j3tstream] did have to add a custom power button to the Pi. This allows the system to boot up and shut down gracefully, preventing system files from being corrupted.

After searching eBay, [j3tstream] found an inexpensive 3.2″ TFT LCD touchscreen display that would work nicely for displaying the traffic data. The display was easy to get working with the Pi. [j3tstream] used the Raspbian linux distribution. His project page includes a link to download a Raspbian image that already includes the necessary modules to work with the LCD screen. Once the image is loaded, all that needs to be done is to calibrate the screen using built-in operating system functions.

The system still needed a data connection. To make things simple and inexpensive, [j3tstream] used a USB WiFi dongle. The Pi then connects to a WiFi hot spot built into his 4G mobile phone. To view the traffic map, [j3tstream] just connects to a website that displays traffic for his area.

The last steps were to automate as much as possible. After all, you don’t want to be fumbling with a little touch screen while driving. [j3tstream] made some edits to the LXDE autostart file. These changes automatically load a browser in full screen mode to the traffic website. Now when [j3tstream] boots up his Pi, it automatically connects to his WiFi hotspot and loads up local traffic maps.

Network Packet Sniffing With Linux

Here’s a chance to learn a little bit about network security. This article walks us through some of the core concepts of network manipulation and packet sniffing using Linux tools. [Joey Bernard] discusses the uses for packages like tcpdump, p0f, and dsniff. They are capable of recording all network traffic coming through your computer’s connection, seeking out machines installed on the network, and listening to traffic for a specific machine. This isn’t going to give you a step-by-step for cracking modern networks. It will provide some insight on what is going on with your network and you should be able to purpose these tools to check that you’ve got adequate security measures in place.

Ego Box Monitors Web Hits

[Bogdan’s] latest project is a box that displays web hits for a chosen site. He calls it the Ego Box because depending on how traffic goes it either bloats or crushes your ego. This provides similar functionality as our Troll Sniffing Rat but the biggest difference is that this is a stand-alone Ethernet device. That’s thanks to the ENC28J60 Ethernet controller chip which manages the stack and has been quite popular in DIY electronic projects. In order to monitor your hits [Bogdan] crafted a bit of code to add to the header of your index page. It increments the counter file each time the page is loaded, and the Ego Box simply monitors that file, displaying the traffic on an eight digit 7 segment display.

[via Adafruit]

Robot Follows The Rules Of The Road

This is a fantastic high school project. [Shmendrik213] built and robot a programmed it to follow common traffic rules. The robot drives itself with a DC motor, using one servo for steering and another to pan a webcam back and forth. The netbook that comes along for the ride is running a VB.NET program that can detect an upcoming intersection, read the street sign, and react based on other cars currently at the intersection.

The hardware is running on an Altera processor using firmware programmed in VHDL. We remember building a tissue box holder for one of our high school projects. Looks like the times have changed since then.