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.
[Adrian] and [Obelix] wanted to have an easy way to know when to expect the public transportation, so they hacked an LED dot matrix display to show arrival times for stops near their dorm.
They found the display on Ebay with a defective controller which they replaced with an ATmega328p. They connected the display to the internet by adding a small TP-Link MR3020 router and connecting it to the ATmega328p via a serial line. Their local transportation office’s web page is polled to gather wait times for the stops of interest. All rendering of the final image to display to the dot matrix display is done on their PC, which then gets pushed through to the MR3020, which in turn pushes it out to the ATmega328p for final display.
[Adrian] and [Obelix] warn about setting proper watchdog timers on the display driver to make sure bugs in the controller don’t fry the dot matrix elements. Their ATmega328p dot matrix driver code can be found on [Adrian]’s GitHub page.
Check out a video of the display in action after the jump.
Continue reading “Public Transportation Display”
Seen at the center of this image is a TP-Link TL-MR3020 which is basically a TL-WR703N wireless router with a few extra LEDs. We’ve seen a lot of projects using this hardware and that’s because it’s cheap and ripe for hacking. The devices can run OpenWRT, a Linux distro for routers that greatly extends the functionality when compared to the stock firmware. Now a couple of members of Shackspace — a hackerspace in Stuttgart, Germany — have written a script that automatically generates specialized firmware for the router. That link goes to their wiki page about the script, but you may find this overview post to be an easier read.
The concept is that gathering specialized hacks into easy to flash packages does away with a lot of configuration headaches. For example, if you just want to play around with an NFC reader for a day-long event you can connect hardware like what is seen above and use the NFC-gate option of the script to flash firmware meant to drive it. So far there’s also support for streaming a USB webcam, serving as a USB network bridge, and a few others. But the whole point of this is to make it simple to roll new firmware mods into the script that make it easy to preserve the work for use at a later time.