RFLink for Sonoff RF Bridge 433 (ESP8266 based WiFi to RF transceiver)?

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Gamester17
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RFLink for Sonoff RF Bridge 433 (ESP8266 based WiFi to RF transceiver)?

#1 Post by Gamester17 » 05 Sep 2017, 16:22

Any chance that we could get a version of RFLink for Sonoff RF Bridge 433 (which is based on ESP8266/ESP8285) by Itead Studio?

https://www.itead.cc/sonoff-rf-bridge-433.html

Sonoff RF Bridge 433 is a cheap prebuilt box with RF transceiver to support WiFi to RF 433MHz and RF 433MHz to WiFi converter

https://www.itead.cc/wiki/Sonoff_RF_Bridge_433

Video:

https://www.youtube.com/watch?v=wTqQ_cmweuo

Do you think that RFLink could be made to run fine on an ESP8266? If it could then this could be cheap way for users to run it.

Here is an article on hacking it with third-party firmware and testing with old RF switches sets (be sure to read the comments):

http://tinkerman.cat/hacking-sonoff-rf-bridge-433/

Video of third-party firmware Espurna used on Itead Studio Sonoff RF Bridge 433:

https://www.youtube.com/watch?v=uGilGeCAV98
Last edited by Gamester17 on 03 Oct 2017, 09:52, edited 5 times in total.

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Stuntteam
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Re: RFLink for Sonoff RF Bridge 433 (ESP8266 based WiFi to RF transceiver)?

#2 Post by Stuntteam » 05 Sep 2017, 17:01

Based on their circuit diagram:
The RF Bridge's main cpu appears to be an EFM8BB1 an 8-bit C8051 core @ 25 MHz. It would have 8k flash, 512 bytes ram.. That is pretty limited.

To be complete, RX/TX is done with a SYN115/470R.
The EFM cpu is controlling the 433mhz RF parts.
There is also the ESP8266 which is handling the wifi traffic.
is there any downlaodable firmware for this bridge available?
-=# RFLink Gateway Development Team #=-
Introduction: http://www.nemcon.nl/blog2/
Generic Support forum: http://www.esp8266.nu/forum/viewforum.php?f=8

Gamester17
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Re: RFLink for Sonoff RF Bridge 433 (ESP8266 based WiFi to RF transceiver)?

#3 Post by Gamester17 » 06 Sep 2017, 08:20

Stuntteam wrote:
05 Sep 2017, 17:01
is there any downlaodable firmware for this bridge available?
Two popular third-party open source firmware for Sonoff devices that supports this bridge already are "Sonoff-Tasmota" and "ESPurna", see:

https://github.com/arendst/Sonoff-Tasmota (checkout: https://github.com/arendst/Sonoff-Tasmo ... bridge.ino )

https://bitbucket.org/xoseperez/espurna (checkout: https://bitbucket.org/xoseperez/espurna ... ew-default )

Otherwise know that Itead Studio have a good reputation of being open source friendly and know to give out code if and when its community asks.

https://github.com/itead

Itead Studio is also known for taking hardware feedback from its community seriously so might be open to make a ESP32 model if there is a demand.

They make and sell both ESP32 and ESP8266 low-cost modules so should not be too much of a stretch if you could convince them there is a market.

https://www.itead.cc/psh-c32.html

I heard as well that Xose Perez (a.k.a. Tinkerman.cat) who develops the ESPurna firmware is planning on posting a dedicated blog post of it soon at:

http://tinkerman.cat

PS: If the ESP8266 is not enough to run RFLink, would a ESP32 be good enough? Again, if so then Itead might be open to replace it if get feedback.

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Re: RFLink for Sonoff RF Bridge 433 (ESP8266 based WiFi to RF transceiver)?

#4 Post by Stuntteam » 06 Sep 2017, 09:50

The ESP tells the EFM cpu what to transmit. The protocol for this is explained on their site.
This is however limited to 24 bits. Thus many of the protocols supported by RFlink will not fit.
We would need to extend that protocol a lot just to put rflink on the ESP and be able to do nice things.
Extending the protocol means reprogramming the EFM cpu.. and there is no info on the EFM and the code in there.
So far it looks like a piece of junk.
-=# RFLink Gateway Development Team #=-
Introduction: http://www.nemcon.nl/blog2/
Generic Support forum: http://www.esp8266.nu/forum/viewforum.php?f=8


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Stuntteam
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Re: RFLink for Sonoff RF Bridge 433 (ESP8266 based WiFi to RF transceiver)?

#6 Post by Stuntteam » 13 Sep 2017, 17:26

No, the issue is not the ESP.. that part is fine..
The issue is the EFM cpu.. which controls the 433mhz RX and TX parts.

The itead bridge is simply an ESP sonof with a pretty crappy 8051 cpu to send very basic 433mhz RF signals.
Without being able to reprogram the EFM we can not add support for additional protocols.
The EFM is also very limited, so even when we could reprogram it, it might not be powerful enough to do a good job.
-=# RFLink Gateway Development Team #=-
Introduction: http://www.nemcon.nl/blog2/
Generic Support forum: http://www.esp8266.nu/forum/viewforum.php?f=8

Gamester17
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Re: RFLink for Sonoff RF Bridge 433 (ESP8266 based WiFi to RF transceiver)?

#7 Post by Gamester17 » 03 Oct 2017, 09:46

@Stuntteam, if you could reengineer this Sonoff RF Bridge as a "Pro" version, which chips would you then use instead? Just a much more powerful and reprogramable EFM chip or more? ESP32 and a powerful and reprogramable EFM chip?

Before you answer, please checkout this article on hacking the Sonoff RF Bridge => http://tinkerman.cat/hacking-sonoff-rf-bridge-433/

Please be sure to read all the comments dicussions in that article which contain more constructive development notes.

schwa226
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Re: RFLink for Sonoff RF Bridge 433 (ESP8266 based WiFi to RF transceiver)?

#8 Post by schwa226 » 15 Nov 2017, 12:36

Hi,

I also got a RF Bridge in my hands...

But as the SONOFF ESPRuna firware is very good, the firware for the EMF8BB1 is very poor.
The board do have the C2 and C2Ck pins routed to read/write the flash of the EMF8BB1 chip.
(I just used a Arduino UNO as a programmer to read the flash)

Attached you will find the original flash (8192 bytes) and a assembler file for this binary.

Anyone to have interests to make a custom firmware for the Silabs RMF8BB1 chip?
There is the documentation for this chip:
https://www.silabs.com/documents/public ... BB1-RM.pdf

What DoTo:
Write a new firmware in "readable" code what is able to handle the original function.
Adapt the new firmware to handle other RF protocols.

EDIT:
I have written a small LED blink for the EFM8 with Simplicity Studio:
https://github.com/MacroFab/Macro_Artic ... e/MF_Blink

After flashing the red LED is blinking... :mrgreen:
Attachments
flash.bin.zip
(2.66 KiB) Downloaded 12 times
flash.asm.zip
(5.69 KiB) Downloaded 11 times

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