RTL SDR 4. 33. 9. Mhz ASKOOK Decoding of Various Devices with rtl4. Since I got into the rtl sdr craze, one thing Ive always been interested in doing is decoding various sensors and remote controls which operate using RF. In order to do this, you must first acquire the signal, understand its modulation FSK, OOKASK and deconstruct its transmission format preamble, data fixed, variable, encoding, error correction. It can be a pretty difficult job and I have rarely had patience to persist with a particular device beyond trivial attempts to understand their formats e. Efergy HM0. 1. Thanks to rtl4. DirectSOFT FAQ0007 29May2002 Q What files are effected by a save A For details, see file DSP save and load chart2. PDF. The following is a summary of the. But do tailor your answer to your audience. My Lifehacker colleagues choose the title blogger or journalist depending on how much theyre ready to get. Benjamin Larsson, we have a starting point. I guess this post isnt going to be new to some people, so feel free to ignore it if youre not interested. Getting Started. Its not hard to get started a git clone and following the build instructions should leave you an rtl4. Invoking it with. Its pretty much as simple as that. One thing to note is that the rtl4. It may even be out of date in the future if rtl sdr makes some new developments, so just be aware of this. The great thing about open source is that its all there for tinkering. Trust me, you will want to tinker say if you intend to do data logging to print to file or stdout instead of stderr, and to add in dates and times. Ill leave the reader to focus on this it is really only necessary to edit the callback function related to the protocol youre interested in and to log the data you need. Aldi Weather Station. Around October in 2. Download The Sweet James Jones Stories Zip more. Aldi Supermarkets in Australia was selling a weekly special it was branded Ascot Weather Station. It was a clock with a temperature and humidity display for inside and outside and barometric pressure. The outside sensor one was provided and uses a 4. The sensor model number is GT WT 0. The front shows the LCD which shows data when powered, an LED indicating transmission on button press, and the openings for the sensors. The unit accepts two AAA cells for power, and the battery compartment has the force transmit and CelsiusFahrenheit toggle button. There is a three position switch to change the channel, selections are 1, 2 and 3. Being somewhat curious, I wanted to see inside just to check if there would be any clues to what sort of system it was using. Dwg File Viewer Shareware. Unfortunately, inside, it wasnt really telling. You can modify the. Our new Backup Manager v1. It has compatibility with more games, faster load times, more reliable loads, and smoother gameplay. Ham Radio Software on Centos Linux Configuring multitudes of Amateur HAM Radio software for Centos6 Centos5 Linux. Stepbystep instruction for reading Aladdin HASP dongle. Aladdin crack. The bottom plastic box houses the hygrometer and temperature sensor. The main PCB has metal snap buttons, a crystal, a few passives and a chip on board gob top. This is connected by plastic flex to the LCD, and a wire connection to a 4. The three wire connection appears to be Vcc, Data and Ground. A close look at the other side of the transmitter reveals clues about its identity. The model GE0. 8 3. G E Chip Technology HK. The datasheet tells us its an ASK 4. Mhz TX module, thus giving us hope that it would be decodable by rtl4. It turns out that it does work just fine, and its detected with the Prologue protocol decoder indicating the sensor has the same type of message format as the Prologue sensor they had analyzed. With the push button pressed for transmit, it shows button 1. Battery Low seems to fluctuate a bit with this model, but the channel is correctly detected. Invoking rtl4. 33 in analyze gives us information about the signal and the bits. It seems theres an octet of 0s as a pre amble, and the data is transmitted six times over completely. The seventh time, it seems that one of the bits in the last nibble is toggled. Data Logging. I was able to modify the code to generate CSV output for the Prologue format for my needs. I placed the sensor in the freezer, and let it log over time. I managed to repeat this for my fridge too which seems to prove that both are in good temperature range, maybe a tad on the cold side although you cant trust the sensors to be accurate to the degree. In both cases, you can see the compressor on and off cycling in effect. Further to this, it was observed that due to the distance, noise in the signal occasionally resulted in incorrect decodes of data to implausible values wrong channel, temperature way out of range. This is to be expected from ASK which can be interfered with by impulse noise easily, and isnt heavily error protected at all. One Wireless Doorbell Transmitter. I dont have many 4. I have is a wireless doorbell transmitter. This one in question comes from a US company which resells Chinese products under the 1 by One brand. The particular transmitters look like this The rear claims to be a 4. Mhz transmitter, 0. Mhz. Its good news, but what is it made out of I think you can see the reason for me choosing this model it uses CR2. The rear of the PCB seems to suggests Quhwa as the manufacturer, with the design dated to 1. October 2. 00. 9. The model is QH C CE 3. V, and it utilizes a SAW resonator, and a single chip marked MC9. T with no information available. The antenna is based on a printed trace towards the top of the board. To my dismay, the rtl4. But the analyze output is coherent and seems to illustrate its easy to support this in the future. As I have three transmitters, I got the analyze output of the three transmitters. Transmitter 1 signalstart 3. Iteration 1. t 1. Iteration 2. t 1. Pulse coding Short pulse length 8. Long pulse length 2. Short distance 8. Transmitter 2 signalstart 1. Iteration 1. t 1. Iteration 2. t 1. Pulse coding Short pulse length 9. Long pulse length 2. Short distance 9. Transmitter 3 signalstart 7. Iteration 1. t 1. Iteration 2. t 1. Pulse coding Short pulse length 9. Long pulse length 2. Short distance 8. I think its clear that you can notice a pattern from the data. It begins with an octet of 0s preamble. The data itself is 3 bytes, and ends with the three nibbles 0xbc. This is repeated 4. It seems as if they send the data over and over to allow a sleeping receiver some time to notice the signal and confirm it in the presence of noise and or weak signals. I might contact the developer and see if he can quickly code up a callback to handle it. After all, with a wireless doorbell sender, theres only ONE state it can send, i. Theres no configurable code or channel options not user configurable. Conclusion. If you have any 4. Mhz devices which use ASK or OOK not FSK, theres a good chance rtl4. Even if its just the analyze mode output of raw bits, that takes the difficulty of the decoding the physical transmission part away. If you have one of those weather station sensors you know you can get it to work right awayGive it a try.