Hackaday was in Portland last weekend for the Open Hardware Summit. I did a brief recap earlier this week but this post has been on my mind the entire time. The night before the summit, OSH Park (the Purveyors of Perfect Purple PCBs which we all know and love) hosted a Bring-A-Hack at their headquarters. [Laen] knows how to throw a party — with a catered spread and open bar which all enjoyed. The place was packed with awesome hackers, and everyone had something amazing to show off.
In fact, there were far too many people showing off hardware for me to capture all in one evening. But join me after the jump for six or seven examples that really stuck out.
Many of us have had a radio controlled car at some time in our youth, though it’s probable that none all of us entirely mastered it. There are memories of spectacular crashes, and if we were really unlucky, further boosts to Mr. Tamiya’s bank balance as fresh parts had to be fitted.
[Paul Yan] was watching his young son with a radio controlled toy, and was struck by how the two-joystick control layout is not necessarily as intuitive as it could be. By contrast when faced with a console game with first-person view and a steering wheel the boy had no problem dropping straight into play. This observation led him to investigate bringing a console steering wheel to an RC car, and the result is a rather impressive FPV immersive driving experience.
His build took a PS2 steering wheel peripheral with pedals and mated it to an Arduino Uno via a PS2 shield. The Uno talks to a Nordic NRF24L01 RF module, which communicates with another NRF24L01 on the car. This in turn talks to a car-mounted Arduino Micro, which controls the car servos and speed controller.
FPV video is provided by a miniature camera and transmitter from the world of multirotor flying which is mounted on the car and transmits its pictures over 5GHz to a set of monitor goggles. Sadly he does not appear to have posted any of the software involved, though we doubt there is anything too challenging should you wish to try it for yourselves.
The video below shows the car in action, complete with an over-enthusiastic acceleration and crash from his young son. He tells us it’s a similar experience to playing a racing kart game in the real world, and having seen the video we wish we could have a go.
Solar power on a remote-controlled plane would get you unlimited cruising range. Now, a normal land-and-swap-battery process might be good enough for some people, but judging from [Prometreus]’s YouTube channel, he’s a fan of long flights over the Alps, and of pushing long-distance FPV links to the breaking point. For him and his friends, the battery power is definitely the limiting factor in how far / long he can fly.
All of the information we have is in the video, but that’s plenty. [Prometreus] didn’t bother with maximum-power-point tracking, but instead wired up his solar cells to work just about right for the voltage of his batteries and the level of sun that he’s seeing. So it won’t work nearly as well on cloudy days. (Check out this MPPT build that was submitted for the Hackaday Prize.)
He could switch the solar cells in an out remotely, and it’s pretty gratifying to see the consumed current in the battery go down below zero. In the end, he lands with a full battery. How cool is that?
Antennas come in all shapes and sizes, and which one is best depends wholly on what you are doing with it. A very popular choice for sending video from drones is the cloverleaf antenna. It is circularly polarized which is an advantage when you have a moving vehicle. It also reduces multipath interference.
A cloverleaf contains three closed loops spaced at different angles. The antenna works well for transmitting but isn’t ideal for receiving. It is also difficult to tune after building it. However, for the right job, it is a good performer. [Vitalii Tereshchuk] shows how he made a cloverleaf antenna that fits a WiFi router.
First-person-view (FPV) flying, by adding a camera, video transmitter, and video goggles to the meat on the ground, is one of the best ways to experience remote-controlled flight. For just a few hundred dollars, it’s the closest thing you’re going to get to growing wings and flying through the trees of your local park. One of the most popular and cheapest ways to go about this is the Boscam RX5808 wireless receiver – a $9 module able to pull down video from an aircraft over 5.8GHz radio. Stock, this radio module is just okay, but with a few modifications, it can be turned into a very good receiver with a spectrum analyzer and autoscan.
The Boscam RX5808 has three DIP switches to allow for eight different channels for receiving video, and this is where most RC hobbyists stop. But the module also has a very capable SPI interface, and by adding a simple Arduino, the complete capabilities of this receiver can be unlocked.
The core software for the build is [markohoepken]’s rx5808-pro and rx5808_pro_osd, and [crazyheea]’s rx5808-pro-diversity to enable all the capabilities available in the RX5808 receiver. With an off-the-shelf LCD, this mess of wires and boards turns into an auto-scanning spectrum analyzer that’s also able to put video from a drone onto a screen.
[garagedrone] put together a very complete demo video of the entire build. You can check that out below.
With the latest advancements in small, cheap video transmitters, it’s no surprise First Person View remote-controlled aircraft are so popular. It’s the easiest way to get into a cockpit without having to spend thousands of dollars and fifty or so hours on a pilot’s license. Despite all the technical challenges of FPV flying, there’s still one underserved part of recording RC aircraft: third person view, or as it’s more commonly called, ‘handing a camcorder to your friend.’
[Walker Eric] would like to do something about that. He’s always wanted nice videos of him flying his plane, and he can’t film and fly at the same time. He can build a robot, though, and that’s his entry for The Hackaday Prize.
[Walker]’s project uses a base station with a camcorder mounted on a gimbal. The electronics for this setup are surprisingly simple – just a GPS beacon transmitting telemetry down to the base station. By comparing this data to a GPS receiver on the ground station, the direction of the plane can be computed.
There are a few problems with this setup. Altitude measurement with GPS isn’t very accurate, so [Walker] is using a pressure sensor as an altimeter on the GPS beacon. The current setup works great, and is a fantastic improvement over the OpenCV setup [Walker] tested out before moving to GPS.
[Walker] already has some incredible video of him flying some planes and quads around his local field shot with this system. You can check those out below.
Normal WiFi is not what you want to send video from your quadcopter back to the first-person-view (FPV) goggles strapped on your head, because it’s designed for 100% correct, two-way transmission of data between just two radios. Transmission of analog video signals, on the other hand, is lossy, one-way, and one-to-many, which is why the longer-range FPV flights all tend to use old-school analog video transmission.
When you’re near the edge of your radios’ range, you care much more about getting any image in a timely fashion than about getting the entire video sequence correctly after a delay. While WiFi is retransmitting packets and your video is buffering, your quadcopter is crashing, and you don’t need every video frame to be perfect in order to get an idea of how to save it. And finally, it’s just a lot easier to optimize both ends of a one-way transmission system than it is to build antennas that must receive and transmit symmetrically.
And that’s why [Befinitiv] wrote wifibroadcast: to give his WiFi FPV video system some of the virtues of analog broadcast.