Esp32 433mhz communication

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Joined: Mon Jun 04, 2018 2:47 pm

Re: Esp32 433mhz communication

Postby PeterR » Wed Dec 12, 2018 9:14 pm

Indeed. You need to sample >>x2. Remember its noise not the TX that matters.
Send 3 times. Check the last two messages (first trains RF). If in doubt look into forward error correction. Sorted.
The counter argument is that bits are power - If power is an issue then just add a solar panel - he's low volume.
A company may prefer cost but would have the hours to burn.
I'm guessing all those speeds are RS232 and similar.
Well old school slow 1970's RS232. Its the upper limit that matters. Choice any bps the UART offers below 2048bps IMHO. I suggested 1024bps. I doubt the UART would work though.
I have never needed/wanted to go above 1024 bps. All that I have read says that 2048 is your limit with the cheaper RF modules & if that's the supposed limit I would use 1/2 that for starters. You just cannot tell with commercial cheap.
How many sample devices did the github/wiki man use? I'm guessing one for a few minutes & then he boasted ;)

Good luck, its a great project to do from first principles.
& I also believe that IDF CAN should be fixed.

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Joined: Mon Dec 25, 2017 7:28 am

Re: Esp32 433mhz communication

Postby meneldor » Fri Dec 14, 2018 12:10 pm

Im stuck on this for 10+ days. So Ive decided to try it on two arduinos instead. Using all of the mentioned libs with their respective examples for tx/rx. The result is that probably either the receiver or the transmitter doesnt work :lol: I should have tested them early....

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Joined: Tue Jun 27, 2017 10:55 pm

Re: Esp32 433mhz communication

Postby G6EJD-ESP32 » Sat Dec 15, 2018 12:01 am

All of these modules are really quite easy to use
Ideally set the TX carrier on or send a preamble to get the link stable then send your data, the receiver needs to ignore the preamble. Putting the TX carrier on, by holding Din high or low, depending on the modules makes the receiver go quiet and random data stops.
In my example above I just used the serial port connected to the TX and RX it makes for a very simple arrangement.
The maximum bandwidth of these devices is about 2000Hz so don’t try to go too fast, they won’t work, about 2400 baud is a sensible maximum.

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Re: Esp32 433mhz communication

Postby meneldor » Sat Dec 15, 2018 8:28 am

Very interesting, i didnt know i can use serial link. Did you test it with different platforms? For example im trying to send from arduino nano to esp32.

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Joined: Tue Jun 27, 2017 10:55 pm

Re: Esp32 433mhz communication

Postby G6EJD-ESP32 » Fri Dec 21, 2018 11:32 pm

It’s a serial link so platform independent, there are many code examples that use the UNO, but the code is near identical

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Re: Esp32 433mhz communication

Postby abel-lisco » Mon Jan 11, 2021 8:00 pm

yesterday I just posted the following:

Subject: FreeRTOS+CLI(c) for ESP32, and RMT peripheral for Radio Codes (ISM RF band)

We just posted a Github repository that might be of interest for some ESP32 Arduino users.

It contains:
- a modified version of the FreeRTOS+CLI(c), that can be used with the Arduino IDE to build a cli based application with the ESP32 under the Arduino IDE.
- an Arduino interactive sketch (RMTRC), that uses the RMT peripheral to send and receive Radio Codes, as used by RF remote controls in the ISM RF bands (433Mhz, 315Mhz, etc). It allows to send RC codes using the RMT peripheral and the RC-Switch(c) library. It also receives and decodes Radio Codes using the RC-Switch(c) library and the RMT peripheral. It used the FreeRTOS+CLI(c) as the foundation for the cli user interface.
- an Arduino interactive sketch, ledc-h, that provides a cli to access ESP-IDF(c) API for quick prototyping or configuration tests. It provides support for most of driver/ledc.h APIs, and esp32-hal-ledc. It allows you to reproduce one of the examples in the ledc_example.c example of ESP-IDF. It is also based on FreeRTOS+CLI(c).

we hope you find it useful

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Joined: Mon Jan 11, 2021 10:17 am

Re: Esp32 433mhz communication

Postby Vadosik » Tue Jan 12, 2021 2:21 pm

PeterR wrote:
Mon Dec 03, 2018 10:18 am

433 Mhz is simple enough and there seem to be quite a lot of arduino projects to learn from.
You will need to add voltage level shifters to convert between 3.3V and 5V.
It's the best option

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