Build Your Own Dial-up ISP With A Raspberry Pi

The bing-bongs, screeches, and whiirings of a diai-up modem are long forgotten now. For good reason. Dial up was slow, and if you’re one of those unlucky people reading this and waiting for the animated gif above this paragraph to load, you have our condolences. But still, nostalgia. It bit [Doge Microsystems] hard, and now there’s a dial-up ISP on [Doge]’s desk.  Why? For fun, probably, and if you’re going to retrocompute, you might as well go the whole way.

The setup for this astonishing feat of dial-up networking is an ISA modem inside a ‘lunchbox’ computer running what is probably Windows 98. The ‘homebrew POTS’ system is a SIP ATA (which is most certainly obsolete and out of stock, but this one will get you close), and a Raspberry Pi clone running Asterisk.  There’s a serial modem and a USB to serial adapter involved, and a PPP daemon running on the Pi clone answers the incoming call, negotiates authentication, and does the NAT. It’s a networking geek’s dream.

As for what good this is, anyone who asks the question is missing the point entirely. Dial up is slow, horrible, and there’s a reason we don’t use it anymore. However, and there’s always a however, if you’re developing your own serial modem hardware for some weird project, I guess this setup would come in handy. If you’d like to test out a wooden modem, this is the setup for you. Yes, it’s ancient technology no one wants anymore, but that’s how you do it if you want.

Learn About BGP With The Internet Of EvE

When we first saw [Ben Jojo’s] post about the Internet inside EvE Online, we didn’t think we’d be that interested. We don’t play EvE — a massively multiplayer game. But it turns out, the post is really about understanding BGP (Border Gateway Protocol) and how it helps route traffic in large networks. The best part? He actually simulates a network with 8,000 nodes to test out what he’s talking about.

Obviously, you wouldn’t want to fire up 8,000 Raspberry Pi computers for such an experiment. Using Buildroot, he set up a very small Linux image that had the bare minimum required to run the tests. The qemu provided virtualization, including an obscure feature that allows you to transfer data between virtual machines using UDP. The whole thing ran on some pretty beefy hardware in the cloud. Sure, you could have provisioned 8,000 cloud instances, but that would run into some serious money pretty fast, we imagine. As a wrap-up, he even uses BGP to model his local mass transit system.

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Cheap Power Over Ethernet For The ESP32

While most projects we see with the ESP32 make use of its considerable wireless capabilities, the chip can be connected to the wired network easily enough should you have the desire to do so. [Steve] liked the idea of putting his ESP32s on the wired network, but found the need for a secondary power connection burdensome. So he took it upon himself to modify some cheap Power Over Ethernet (PoE) hardware and create a single-cable solution (Google Translate).

[Steve] bought a PoE module intended for security cameras and ran a close eye over the board to figure out what kind of hardware it was using to generate the nominal 12 V output. He identified an MP2494 step-down converter, and with the datasheet in hand found how the output voltage is configured by changing the values of resistors in the circuit. Swapping out the stock 21.5 kΩ resistor for a 57.1 kΩ one changed the output of the converter to the 5 V necessary for his electronics.

But of course that was only half of the problem solved; he still had to connect the Ethernet side of the PoE device to the Waveshare LAN8720 board that’s providing Ethernet for the ESP32. So he removed the RJ45 jack from the LAN8720 completely, and wired that directly to the connector on the PoE board. Helpfully, the PoE board had all the pins labeled on the bottom side so this wasn’t nearly as tricky to figure out as you might expect (if only it was always that easy).

We’ve previously covered the Waveshare LAN8720 board for anyone who’s interested in the ins and outs of getting their ESP32 talking Ethernet. If you’re wondering how you can put PoE to work for you, our very own [Jonathan Bennett] has been showing off his home Raspberry Pi infrastructure which makes extensive use of the new PoE hat.

This Tiny Router Could be the Next Big Thing

It seems like only yesterday that the Linksys WRT54G and the various open source firmware replacements for it were the pinnacle of home router hacking. But like everything else, routers have gotten smaller and faster over the last few years. The software we run on them has also gotten more advanced, and at this point we’ve got routers that you could use as a light duty Linux desktop in a pinch.

But even with no shortage of pocket-sized Linux devices in our lives, the GL-USB150 “Microrouter” that [Mason Taylor] recently brought to our attention is hard to ignore. Inside this USB flash drive sized router is a 400 MHz Qualcomm QCA9331 SoC, 64 MB of RAM, and a healthy 16 MB of storage; all for around $20 USD. Oh, and did we mention it comes with OpenWRT pre-installed? Just plug it in, and you’ve got a tiny WiFi enabled Linux computer ready to do your bidding.

On his blog [Mason] gives a quick rundown on how to get started with the GL-USB150, and details some of the experiments he’s been doing with it as part of his security research, such as using the device as a remote source for Wireshark running on his desktop. He explains that the diminutive router works just fine when plugged into a USB battery bank, offering a very discreet way to deploy a small Linux box wherever you may need it. But when plugged into a computer, things get really interesting.

If you plug the GL-USB150 into a computer, it shows up to the operating system as a USB Ethernet adapter and can be used as the primary Internet connection. All of the traffic from the computer will then be routed through the device to whatever link to the Internet its been configured to use. Depending on how you look at it, this could be extremely useful or extremely dangerous.

For one, it means that something that looks all the world like a normal USB flash drive could be covertly plugged into a computer and become a “wiretap” through which all of the network traffic is routed. That’s the bad news. On the flip side, it also means you could configure the GL-USB150 as a secure endpoint that lets you quickly and easily funnel all the computer’s traffic through a VPN or Tor without any additional setup.

We’ve seen all manner of hacks and projects that made use of small Linux-compatible routers such as the TP-Link TL-MR3020, but we expect the GL-USB150 and devices like it will be the ones to beat going forward. Let’s just hope one of them doesn’t show up uninvited in your network closet.

Solar-Powered OpenWRT Router For Mobile Privacy

Let’s not pretend we aren’t all guilty of it: at some point we’ve all connected to a public WiFi network to check our email or log into some site or service. We know the risks, we know better. But in a weak moment we can let the convenience of that public network get the better of us. What if you had a small secure router that you could use as an encrypted VPN endpoint, allowing you to connect to those enticing public networks while keeping your traffic secure? That’s precisely what [David] had in mind when he built this pint-sized solar-powered OpenWRT router.

At the heart of this gadget is the TP-Link TL-MR3020, a tiny OpenWRT-compatible router that’s no stranger to the pages of Hackaday. Its small size and low cost have made it a natural choice for a wide array of projects, so it’s little surprise that [David] gravitated towards it. But simply getting OpenWRT installed on the MR3020 and configuring OpenVPN doesn’t exactly grant you entrance into the Hackaday Pantheon, so obviously there’s a bit more to the story.

For one, [David] didn’t like the idea of a USB flash drive hanging out of the side of his router. Since the flash drive would essentially be a permanent part of the router, as it is being used to expand the rather meager internal storage of the MR3020 he decided to wack the USB end off the flash drive and solder it directly to the router’s PCB. This gave him a much cleaner looking package, but it still wasn’t as portable as he’d like.

He decided to order a solar-charged USB power bank to become the new home of his hacked MR3020. He kept the solar panel and charge controller from the original gadget, and after some researched settled on a pair of LG-HG2 3000 mAh batteries as the power source. [David] went through a few charge and discharge cycles making sure everything worked as expected before buttoning up the case. In the future he says he might transplant the electronics into a 3D printed case, but for now he’s pretty pleased with the results.

If you’d like to try your hand at hacking these popular micro routers, you’ll need to start with an OpenWRT firmware. After you’ve got a full blown Linux distro running on this little fellow, the only limitation is your own imagination.

The Linux Throwie: A Non-Spacefaring Satellite

Throwies occupy a special place in hardware culture — a coin cell battery, LED, and a magnet that can be thrown into an inaccessible place and stick there as a little beacon of colored light. Many of us will fondly remember this as a first project. Alas, time marches inevitably on, and launching cheerful lights no longer teaches me new skills. With a nod to those simpler times, I’ve been working on the unusual idea of building a fully functional server that can be left in remote places and remain functional, like a throwie (please don’t actually throw it). It’s a little kooky, yet should still deliver a few years of occasional remote access if you leave it somewhere with sunlight.

A short while ago, I described the power stages for this solar-powered, cloud accessible Linux server. It only activates on demand, so a small solar cell and modest battery are sufficient to keep the whole show running.

Where we left off, I had a solar cell that could charge a battery, and provide regulated 12 V and 5 V output. For it to be a functional device, there are three high level problems to solve:

  1. It must be possible to set up the device without direct physical access
  2. You must be able to remotely turn it on and off as needed.
  3. It needs to be accessible from the Internet.

The funny thing is, this hardware reminds me of a satellite. Of course it’s not meant to go into space, but I do plan to put it somewhere not easy to get to again, it runs off of solar power, and there’s a special subsystem (ESP8266) to tend the power, check for remote activation, and turn the main computer (Raspberry Pi 3) on and off as necessary. This sounds a lot like space race tech, right?

As I have a bit more code than usual to share with you today, I’ll discuss the most interesting parts, and provide links to the full firmware files at the end of the article.

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Bill’s 100 Year-Old Smart Home

[Bill]  purchased a house in Central Florida, and like any good hacker, he started renovating, pulling Ethernet cables, and automating things. Lucky for us, he decided to write up his experiences and lessons learned. He found a few problems along the way, like old renovations that compromised the structure of the pool house. After getting the structural problems sorted, he started installing Insteon smart switches. If automated lighting is of interest, and you don’t want to wire up relays yourself, Insteon might be the way to go.

He linked the buildings together with a wireless bridge, and then worked out how to automatically reset the PoE switch when the wireless bridge hangs, automating that recovery process. For your viewing pleasure, he even has one of the security cameras streaming 24/7 online.

His blog looks like a good resource to keep an eye on, and we wouldn’t be surprised to have more of his work show up here on Hackaday. For more home automation goodness, check out some of our previous articles on the subject.