Bringing A Legacy Pager Network Back to Life

[Jelmer] recently found his old pager in the middle of a move, and decided to fire it up to relive his fond memories of receiving a page. He soon discovered that the pager’s number was no longer active and the pager’s network was completely shut down. To bring his pager back to life, [Jelmer] built his own OpenWRT-based pager base station that emulates the POCSAG RF pager protocol.

[Jelmer] opened up his pager and started probing signals to determine what protocol the pager used. Soon he found the RF receiver and decoder IC which implements the POCSAG pager protocol. [Jelmer] began going through the sparse POCSAG documentation and assembled enough information to implement the protocol himself.

[Jelmer] used a HLK-RM04 WiFi router module for the brains of his build, which talks to an ATMega that controls a SI4432 RF transceiver. The router runs OpenWRT and generates POCSAG control signals that are transmitted by the SI4432 IC. [Jelmer] successfully used this setup to send control signals to several pagers he had on hand, and plans on using the setup to send customizable alerts in the future. [Jelmer] does note that operating this device may be illegal in many countries, so as always, check local frequency allocations and laws before tackling this project. Check out the video after the break where a pager is initialized by [Jelmer]’s transmitter.

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Hacking a $20 WiFi Smart Plug

The Kankun smart plug is an inexpensive device that lets you switch an outlet on and off over wifi. The smart plug only works with an Android or IOS app that ships with the device, which limits its usefulness to turning things on and off from your phone.

In an attempt to make this device more useful, [LinuxGeek] probed the device with nmap and discovered that it runs OpenWRT. After trying various common default passwords he discovered the login was root/admin. While [LinuxGeek] hasn’t sniffed the protocol yet, others have hacked it a bit further. The plug apparently uses UDP packets to communicate with the Android app, but the packets are unfortunately encrypted.

Rather than hack at the protocol, they wrote code that toggles the GPIO pin from a CGI script and developed a small Windows application that hits the CGI script for simple control from a computer. There’s also a Google+ group where more information and a couple other hacks for these plugs are posted. For $20 (from AliExpress) and with a bit of hacking, this smart plug could be a great way to add wireless control to a home automation system.

Playing Doom (Poorly) on a VoCore

Last May brought the unastonishing news that companies were taking the Systems on Chip found in $20 wireless routers and making dev boards out of them. The first of these is the VoCore, an Indiegogo campaign for a 360MHz CPU with 8MB of Flash and 32MB or RAM packaged in a square inch PCB for the Internet of Things. Now that the Indiegogo rewards are heading out to workbenches the world over, it was only a matter of time before someone got Doom to run on one of them.

After fixing some design flaws in the first run of VoCores, [Pyrofer] did the usual things you would do with a tiny system running Linux – webcams for streaming video, USB sound cards to play internet radio, and the normal stuff OpenWrt does.

His curiosity satiated, [Pyrofer] turned to more esoteric builds. WIth a color LCD from Sparkfun, he got an NES emulator running. This is all through hardware SPI, mind you. Simple 2D graphics are cool enough, but the standard graphical test for all low powered computers is, of course, Doom.

The game runs, but just barely. Still, [Pyrofer] is happy with the VoCore and with a little more work with the SPI and bringing a framebuffer to his tiny system, he might have a neat portable Doom machine on his hands.

Anonabox: How To Fail Horribly at Kickstarter

Late last week, Anonabox hit Kickstarter, glomming on to concerns over security, privacy, and censorship. The project was picked up on the usual tech blogs, lauding this project as the pinnacle of the Open Source, Open Hardware movement and a great investment for the privacy-minded technocrat in a post-Snowden world.

Then, the creator of Anonabox did an AMA on reddit. It was quickly discovered that the entire project was an off the shelf router found on AliExpress with reflashed firmware. The router sells for $20 in quantity one, and the Anonabox Kickstarter is giving them away with a minimum $51 pledge. The new firmware is basically a standard OpenWrt installation with a few changes to the config files. The project claims to solve the problem of hardware backdoors, but ships with a backdoor root password (the password is ‘developer!’), open WiFi, and ssh open by default. The Anonabox also claims to be a plug and play solution to security and privacy on the Internet, meaning if this project ever ships, there will be a lot of people who won’t change the default configuration. That’s rather hilarious in its implications.

According to the Kickstarter campaign, the Anonabox has gone through four years of development and four generations of hardware. [August] even has a great graphic demonstrating that each successive generation has reduced the size in half and doubled the system resources:

Image taken from Kickstarter campaign

Anyone with the slightest eye for detail will quickly realize that components, like Ethernet jacks, SD cards, and CF cards are always the same size. I wonder what this graphic would look like if all the boards were scaled so they were in proportion to each other?

Image rescaled so all boards are proportional to each other

Oh. That’s not fishy at all.

As with most Kickstarters that have seen this much negative attention, the project was suspended just a few hours ago, but not before gathering more than $600,000 in pledges at its peak.


Although the Anonabox failed, there is a market for a Tor-enabled router, and luckily we have one on It’s so great that some of the copy for the Kickstarter campaign was lifted directly from this project. With a wealth of market research available, we can only hope that [CaptainStouf] runs his own campaign for the UnJailPi.

The Arduino Yun Shield


A few years ago, the most common method to put an Arduino project on the web was to add a small router loaded up with OpenWrt, wire up a serial connection, and use this router as a bridge to the Internet. This odd arrangement was possibly because the existing Arduino Ethernet and WiFi shields were too expensive or not capable enough, but either way the Arduino crew took notice and released the Arduino Yun: an Arduino with an SoC running Linux with an Ethernet port. It’s pretty much the same thing as an Arduino wired up to a router, with the added bonus of having tons of libraries available.

Since the Yun is basically a SoC grafted onto an Arduino, we’re surprised we haven’t seen something like this before. It’s an Arduino shield that adds a Linux SoC, WiFi, Ethernet, and USB Host to any Arduino board from the Uno, to the Duemilanove and Mega. It is basically identical to the Arduino Yun, and like the Yun it’s completely open for anyone to remix, share, and reuse.

The Yun shield found on the Dragino website features a small SoC running OpenWrt, separated from the rest of the Arduino board with a serial connection. The Linux side of the stack features a 400MHz AR9331 (the same processor as the Yun), 16 MB of Flash, and 64 MB of RAM for running a built-in web server and sending all the sensor data an Arduino can gather up to the cloud (Yun, by the way, means cloud).

All the hardware files are available on the Yun shield repo, with the Dragino HE module being the most difficult part to source.

A Router-Based Dev Board That Isn’t A Router

Here’s somethirouterng that be of interest to anyone looking to hack up a router for their own connected project or IoT implementation: hardware based on a fairly standard router, loaded up with OpenWRT, with a ton of I/O to connect to anything.

It’s called the DPT Board, and it’s basically an hugely improved version of the off-the-shelf routers you can pick up through the usual channels. On board are 20 GPIOs, USB host, 16MB Flash, 64MB RAM, two Ethernet ports, on-board 802.11n and a USB host port. This small system on board is pre-installed with OpenWRT, making it relatively easy to connect this small router-like device to LED strips, sensors, or whatever other project you have in mind.

The board was designed by [Daan Pape], and he’s also working on something he calls breakoutserver There’s a uHTTP server written specifically for the board that allows any Internet connected device to control everything on the board. There’s also an HTML5 app they’re developing which could be pretty interesting.

All in all, it’s a pretty cool little device that fits nicely in between the relatively simplistic ‘Arduino with an Ethernet shield’ and a Raspi or BeagleBone.

Android Doorbell Notifier

Breadboarded circuit to detect when doorbell rings

It’s always unfortunate to find a FedEx tag on your door saying you missed a delivery; especially when you were home the whole time. After having this problem a few times [Lee] decided to rig up a doorbell notifier for his Android phone.

[Lee]’s doorbell uses a 10 VAC supply to ring a chime. To reduce modifications to the doorbell, he added an integrated rectifier and a PNP transistor. The rectifier drives the transistor when the bell rings, and pulls a line to ground.

An old Netgear router running OpenWRT senses this on a GPIO pin. Hotplugd is used to run a script when the button push is detected.

The software is discussed in a separate post. The router runs a simple UDP server written in C. The phone polls this server periodically using SL4A: a Python scripting layer for the Android platform. To put it all together, hotplugd sends a UNIX signal to the UDP server when the doorbell is pushed. Once the phone polls the server a notification will appear, and [Lee] can pick up his package without delay.