Ever make something just to see if you could? Yeah, we thought so. [serverframework] wanted to see if he could clone the remote that opens his neighborhood gate, inspired by the long distance ding-dong-ditch efforts of [Samy Kamkar].
This clone uses an ATtiny85 and an RF module to emulate and send the frequency that the gate is waiting for. To accomplish that, [serverframework] had to figure out both the operating frequency and the timing used by the remote. The crystal inside seemed to indicate 295 MHz, and a quick check of the device’s FCC registration confirmed it. Then he used an SDR dongle to watch the data coming across when he pressed the button, and ran it through Audacity to figure out the timing.
Unfortunately, the 295 MHz crystal is a rare beast, so [serverframework] had to transplant the original to the donor RF module. Then it was just a matter of programming the ATtiny85 to send the frequency with the right timing. It actually does a better job since the original has no timing crystal, and the ‘tiny is clocked with a standard 16 kHz oscillator. The code is available within [serverframework]’s excellent write-up, and you can see a tiny demo after the break.
There’s more than one way to clone a gate remote. This one leverages MQTT to turn friends’ phones into remotes.
Continue reading “Cloned Gate Remote Does It (Slightly) Better”
Does your Gated Community make you feel secure due to the remote-controlled gate keeping the riffraff out? Residents of such Gated Communities in Poland are now shaking in fear since [Tomasz] has hacked into his own neighborhood by emulating the signal that opens the entrance gate. Shockingly, this only took about 4 hours from start to finish and only about $20 in parts.
Most of these type of systems use RF communication and [Tomasz’s] is no difference. The first step was to record the signal sent out by his remote. A USB Software Defined Radio transmitter/receiver coupled with a program called SDR# read and recorded the signal without a hitch. [Tomasz] was expecting a serialized communication but after recording and analyzing the signal from several people entering the community it became clear that there was only one code transmitted by everyone’s remote.
Now that he knows the code, [Tomasz] has to figure out a way to send that signal to the receiver. He has done this by making an RF transmitter from just a handful of parts, the meat and potatoes being a Colpitts oscillator and a power amplifier. This simple transmitter is connected to a DISCOVERY board that is responsible for the modulation tasks. [Tomasz] was nice enough to make his code available on his site for anyone that is interested in stopping by for a visit.
I was plotting one of my future projects and found this diy RF remote control. I was struck by how simple the circuits are thanks to the micro-controller and RF modules. This is an older write up, and I know you can get newer modules from Spark Fun electronics, but when I was younger, RF controls always seemed to be the black magic of diy electronics.