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Before I start, please note I am not even near to be an expert in electronics - I just try to do my best with what I have - I apologize in advance if my language is not technical enough.

I have a power generator that can be started using an included remote controller transmitting at 433.68 MHZ according to the FCC ID (https://fccid.io/YA3V750)

I already contacted the manufacturer and they literally told me they don't make any kind of hardware to automate the power generator (of course, they offered me a new one with this functionality included).

AFAIK, the transmitters / receivers available for Arduino are either 315/433 MHZ, but I am somewhat concerned that, if the power gen receiver is set to 433.68 MHZ, it might not receive the 433 mhz signal.

So far I already devised a plan and schema for closing switches using relays, activating servos for gas and main power switch, Hall sensors for detecting when the power is out, or the voltage is low... so now I am facing this little issue: When Arduino detects main power is gone, it should send the start signal to the power generator using a rf transmitter; once power is back, send the stop signal - but at 433.68 MHZ.

Any opinions / suggestions?

Thanks in advance.

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  • \$\begingroup\$ Would it be reasonable to just hack apart the remote and simulate button presses with the Arduino? \$\endgroup\$ – Brendan Simpson May 12 '16 at 19:52
  • \$\begingroup\$ I opened the controller, but the circuit is just soo small and tiny I fear I will screw things up if try to soldier something there \$\endgroup\$ – Edgar E. May 14 '16 at 19:17
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The "433MHz ISM Band" extends from 433.05 MHz to 434.79 MHz. (ISM = "Industrial Scientific and Medical".) "433MHz" transmitters and receivers are programmed for whatever specific frequency you want to transmit (or receive) on.

For example, the very popular HopeRF product: RFM22B can be programmed to operate from 413 to 453 MHz. (Well below and above the official band.) See the referenced data sheet, page 5. This is just one example of most "433MHz" products.

To talk to your 433.68 MHZ generator, you would simply use your Arduino code to tell your RF module to transmit at 433.68 MHz.

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  • \$\begingroup\$ Please note that you must ALSO determine WHAT the transmitter is sending so that you can reproduce it. If it is a simple "press the button once to turn it on, and again to turn it off" function. Then maybe it just needs some strong signal near 433 MHz. But if it is more sophisticated than that, the remote may be sending some stream of data that the receiver is expecting to hear. So you must receive and document what the data stream is, and then you must reproduce it with a microcontroller or whatever. \$\endgroup\$ – Richard Crowley May 16 '16 at 22:43
  • \$\begingroup\$ do you think I could use this device instead of the hopeRFM22B? Apparently it´s easier to get it for me... ebay.com/itm/… \$\endgroup\$ – Edgar E. Jun 1 '16 at 15:33
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    \$\begingroup\$ Yes, that appears to use a Texas Instruments CC1101 chip which looks like it can be programmed for your 433.68MHz requirement. You will first need to configure it as a RECEIVER to intercept and analyze what bit-pattern signal your transmitter is sending. Then you can program your microcontroller to send the same bit-pattern using the CC1101 Doc: ti.com/product/CC1101 Example: labalec.fr/erwan/?p=497 \$\endgroup\$ – Richard Crowley Jun 1 '16 at 17:24
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It depends on how sensitive the generator's receiver is to the exact frequency. Most receivers I have come across are not that picky about the frequency.

In the transmitter there is a resonator which is made for a very specific frequency, like 433.68 MHz in your case. This is done so that it will transmit only in the allowed frequency band.

The receiver does not have to be sensitive to only this frequency because the transmitter usually sends out a certain code, a sequence of on/off which represents a number. For example my garage door uses this and there are 1 million possible numbers, but of course only the number will open the door. Only when the right number is received (at which frequency is not so important) will the receiver activate.

My guess is that your generator uses a similar scheme and that a standard 433 MHz transmitter can activate it but you need to know which number to send. You can find out with a cheap 433 MHz receiver connected to an Arduino, then use the remote for your generator. The Arduino will then decode the number.

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  • \$\begingroup\$ Yes, my thoughts exactly for decoding the number...thank you!! \$\endgroup\$ – Edgar E. May 14 '16 at 0:27
  • \$\begingroup\$ This isn't really the case. In reality, 433.00 MHz isn't even a legal frequency in the "433MHz ISM band". There are MANY channels in the "433MHz band, and 433.68 is just one of them. If you need to transmit to something that is receiving at 433.68MHz, then you program the transmitter to use that frequency. It is as simple as that. 433MHz transmitters and receivers are constructed to effectively transmit and receive on the entire 433.05 MHz to 434.79 MHz band. It is just a matter of programming the transmitter or receiver. \$\endgroup\$ – Richard Crowley May 15 '16 at 6:38
  • \$\begingroup\$ @RichardCrowley You assume that all 433 MHz products use a PLL based transceiver and the simple fact is that most don't. Many keyfob transmitters use a resonator to set the frequency, you'd have to change the resonator to change the frequency. For many cheap receivers it's the same, they have no PLL and cannot be programmed. This is not a problen, it simply receives the whole band and looks for the code that it's paired transmitter sends out. I'm talking about the 433 MHz sets that cost half of what the RFM22B costs. For a simple consumer product, a RFM22B solution is expensive. \$\endgroup\$ – Bimpelrekkie May 15 '16 at 10:06
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    \$\begingroup\$ There are many tutorials and instructions online that tell how to "capture" the code from a remote control. Most of them are written for infra-red (like TV receiver remotes, etc.) But once you have the RF1101SE programmed to receive 433.68 MHz, it should be able to receive the code from the existing remote. Then you can simply reproduce that code and transmit it from the same RF1101SE. \$\endgroup\$ – Richard Crowley Jun 29 '16 at 6:12
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    \$\begingroup\$ The CC1101 is not a "mainstream" product for which you will find a lot of code. We don't know why you chose that product unless you are an experienced programmer. When I Googled for "clone a remote signal" it returned over half a million hits. Most of the popular ones are based on Arduino. \$\endgroup\$ – Richard Crowley Jul 2 '16 at 19:39
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If you've got a manual remote, could you replace the buttons on the remote with some small relays and get the arduino to drive the relays? That way you bypass the whole issue of getting the right frequency/activation codes. (I'd recommend staring with small relays as you don't know how the switches were wired in and the isolated contacts in a relay means you don't have to worry about that)

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  • \$\begingroup\$ You know? I thought about this, but I´m a little bit skeptical because of the size of the buttons -- they are even smaller than the reset button an Arduino Mega... so, soldering anything there will most likely end up in a total mess and a bricked remote controller....at least for me \$\endgroup\$ – Edgar E. May 14 '16 at 0:30

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