Hacking 2.4GHz Radio Control

Many modern radio control (RC) systems use frequency hopping to prevent interference. Unfortunately, hopping all over the 2.4GHz band can interfere with video or WiFi using the same frequency band. [Befinitiv] was trying to solve this problem when he realized that most of the systems used a TI CC2500 chip and a microcontroller. The microcontroller commands the chip via SPI and controls the frequency by writing into a frequency register.

Updating the microcontroller firmware was impractical. The firmware is encrypted, for one thing. In addition, the change would have to be reinserted on any future updates and repeated for every RC vendor. So [Befinitiv] took a different approach. He did a classic man in the middle attack by inserting an CPLD in between the controller and the CC2500.

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Using RC Transmitters With Flight Simulators

It’s winter, and that means terrible weather and very few days where flying RC planes and helicopters is tolerable. [sjtrny] has been spending the season with RC flight simulators for some practice time. He had been using an old Xbox 360 controller, but that was really unsuitable for proper RC simulation – a much better solution would be to use his normal RC transmitter as a computer peripheral.

The usual way of using an RC transmitter with a computer is to buy a USB simulator adapter that emulates a USB game pad through a port on the transmitter. Buying one of these adapters would mean a week of waiting for shipping, so [sjtrny] did the logical thing and made his own.

Normally, a USB simulator adapter plugs in to a 3.5mm jack on the transmitter used for a ‘buddy box’, but [sjtrny] had an extra receiver sitting around. Since a receiver simply outputs signals to servos, this provides a vastly simpler interface for an Arduino to listen in on. After connecting the rudder, elevator, aileron, and throttle signals on the receiver to an Arduino, a simple bit of code and the UnoJoy library allows any Arduino and RC receiver to become a USB joystick.

[sjtrny] went through a second iteration of hardware for this project with a Teensy 3.1. This version has higher resolution on the joystick axes, and the layout of the code isn’t slightly terrible. It’s a great project for all the RC pilots out there that can’t get a break in the weather, and is also a great use for a spare receiver you might have sitting around.

Hackaday Links: December 21, 2014

Most of the incredible flight simulator enthusiasts with 737 cockpits in their garage are from the US. What happens when they’re from Slovenia? They built an A320 cockpit. The majority of the build comes from an old Cyprus Airways aircraft, with most of the work being wiring up the switches, lights, and figuring out how to display the simulated world out of the cockpit.

Google Cardboard is the $4 answer to the Oculus Rift – a cardboard box and smartphone you strap to your head. [Frooxius] missed being able to interact with objects in these 3D virtual worlds, so he came up with this thing. He adapted a symbol tracking library for AR, and is now able to hold an object in his hands while looking at a virtual object in 3D.

Heat your house with candles! Yes, it’s the latest Indiegogo campaign that can be debunked with 7th grade math. This “igloo for candles” will heat a room up by 2 or 3 degrees, or a little bit less than a person with an average metabolism will.

Last week, we saw a post that gave the Samsung NX300 the ability to lock the pictures taken by the camera with public key cryptography. [g3gg0] wrote in to tell us he did the same thing with a Canon EOS camera.

The guys at Flite Test put up a video that should be handy for RC enthusiasts and BattleBot contenders alike. They’re tricking out transmitters, putting push buttons where toggle switches should go, on/off switches where pots should go, and generally making a transmitter more useful. It’s also a useful repair guide.

[Frank Zhao] made a mineral oil aquarium and put a computer in it. i7, GTX 970, 16GB RAM, and a 480GB SSD. It’s a little bigger than most of the other aquarium computers we’ve seen thanks to the microATX mobo, and of course there are NeoPixels and a bubbly treasure chest.

Hackaday Links, September 14, 2014

Photonicinduction is back! The Brit famous for not setting his attic on fire has built a 20,000 Watt power supply. It connects directly to England’s national grid with huge connectors. Impeccable fabrication and triple servo controlled variacs, and apparently this will be used for making a lot of hydrogen and oxygen through electrolysis of water.

In case you missed it, there’s a group buy for Flir’s Lepton thermal imaging module. Here’s the breakout board.

Need to solder something away from an outlet, and all you have is a disposable lighter? There’s a fix for that.

A Raspberry Pi case designed to be compatible with Lego. Now we need a hat/shield for NXT connectors.

Need another channel in your RC remote? Here’s this. It uses the gyro gain channel on a receiver. If someone wants to figure out how this works, wee do have a rather cool project hosting site.


Here’s something impossibly cool: The Macintosh PowerBop. It’s a Powerbook 170 with the floppy drive replaced with the radio in a cordless phone. It was part of France’s BiBop network, and you could buy private base stations for use at home. It is technically possible to use the radio as a wireless link to a modem, but [Pierre] couldn’t get PPP or a sufficiently ancient browser working. Plus ten points for taking it to an Apple store, and another twenty for trying to connect to our retro edition.

Chicken Lips. [Fran] and our very own [Bil Herd] are hanging out a bunch and recalling [Bil]’s time at Commodore. For this little featurette, [Bil] brought out his very own Commodore LCD. There are three of those in the world. Also included: tales of vertical integration, flipping bits with photons, and 80s era ERC.

Repairing a Damaged RC Rx Due to Reverse Polarity Power Input

Rx Receiver Repair

Once in a while all of us technocenti get a little complacent and do something that may be considered ‘dumb’ while working on a project…. like cutting the wrong side of a piece of wood or welding a bracket on in the wrong direction. [Santhosh] is human like everyone else and plugged in the power connector to his RC Receiver incorrectly, rendering the receiver useless. How will his Arduino-controlled Robot work without a functioning receiver?

[Santhosh] started by opening up the case to expose the circuit board and checking out the components inside. The first component in the power input path was a voltage regulator. Five volts DC was applied to the input side of the 3.3-volt regulator but only 1.21 came out the other end. Now that the problem was quickly identified the next step was to replace the faulty regulator. Purchasing an exact replacement would have been easy but cost both time and money. [Santhosh]’s parts bin contained a similar regulator, a little larger than the original but the pinout was the same.

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Adding shoulder buttons to an RC transmitter


[Gerard] does puppeteering and animatronics work, and to remotely control his creations and characters he uses an off-the-shelf remote control radio. It’s you basic 6-channel setup, but [Gerard] wanted a way to control eye blinks and other simple actions with the press of a button. Sure, he could use the toggle switches on his transmitter, but he wanted something that wouldn’t require turning a servo on and off again. To fix this problem, [Gerard] added shoulder buttons to his transmitter with only a little bit of soldering.

[Gerard]’s transmitter uses toggle switches to send a signal on channels five and six. To add his push buttons, he simply drilled a hole in the plastic enclosure, installed a pair of push buttons, and wired them in parallel to the toggle switches.

Now [Gerard] has momentary switches on channels five and six, perfect for making his creations blink. Since the buttons are wired in parallel with the switches, flicking the switches to the ‘on’ position in effect takes the button out of the circuit, just in case the transmitter gets jostled around.