[Hardware Tip] 433 MHz Receiver for Pimatic

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To avoid questions about bad reception of 433MHz transmissions please have a look at this short threat here.

There are several RF receivers available but PLEASE go for the 3400 RF receiver since it’s worth the money !!

Make sure the quartz says 433 (there are also 315MHz devices available)

The back of it says RXB6

You will find it on ebay at several sellers for approx. 5 - 10 Euro

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PLEASE DO NOT TAKE CHEAP RECEIVERS LIKE XY-MK-5V
They have only limited range (mostly under 1 meter!).
You can solder an antenna and play with different voltages but this doesn’t help much.

Tips for other good RF receivers are very welcome

Tested receivers :

Picture	Type	Range	Notes
	RXB6	15 - 20 Meters	Best tested range, comes as bundle with transmittee as 3400RF or sold seperately.
	RXB8	10 - 15 Meters	Good range, similar to RXB6, little bit smaller in size
	SRX882	< 5 Meters	Different findings about range and hardware. My findngs - not good! Very low range. Sold with sender STX882 which is not good either. Does not support all protocols.
	Aurel AC-RX	< 5 Meters	Very low range, too expensive (appr. 8 Euro), not recommended!
	xy-mk-5v	< 5 Meters	Very low range, not recommended! Sold with sender FS1000a which is ok to use.

@leader21, Absolutely right! With XY-MK-5V the range is poor - for me it was no more than 3 metres. With the RXB6 (shielded version) and a simple wire antenna the range is 20 metres at least.

SRX882 STX882
I can also highly recommend this set for round about 11€. It includes 5 transmitter, 5 receiver and 10 nice antennas. I had some trouble to get it working.The Receiver has a CS pin, which needs a high level to activate the module. So I solder a bridge between VCC and CS. Tested the range today and there is no place in my house/garden, where the SRX882 not receive the signal. In the farthest corner of the garden, it would be about 40m with a wall in between.

nice tip, will order a set. Thanks!

These don’t include header pins, right? Don’t see them on your picture

@lxz Right. No header pins!

@lxz
right no header pins.
link updated.
The price is a bit higher now. The seller has other offers…
so visit the shop

Maybe a slightly late reaction (but I’m also just new), but I have the RXB6 receiver as well. As it comes with an Antenna pin I simply pushed a female Dupont wire on that antenna pin and cut it to 17 cm.
Works perfect as well and increases the range with at least 5-8 meters…

Someone should make a thread about the antennas for RXB6, how to cut the right lenght (for example when using a dupont), or experiences with different antennas (with pictures would be great).

I am using a female end dupont as well at the moment, and it is working, but the working distance could be much better. My home door is around one corner and 4 meters, and the door contact sensor does pick up. But if I move Raspberry one or two meters away, it will stop picking it up.

Therefore it could be good to have a thread about working distances for different antennas and devices.

@magic-tune you are using it with the atiny? Is it Vetter than rxb6 in your opinion?

@kitsunen said:

Someone should make a thread about the antennas for RXB6, how to cut the right lenght (for example when using a dupont), or experiences with different antennas (with pictures would be great).

There are some posts over in this thread. http://forum.pimatic.org/topic/24/433-mhz-receiver-how-to-get-a-better-reception/41 The theoretical correct length is a multiple of the wavelength for 433.92Mhz. This is why you see numbers like 172.3mm and 344.6mm floating around, they’re 1/4 and 1/2 wavelength dipole antennas respectively. Keeping the position of everything including the transmitter, receiver, and you in the same positions help getting consistent results.

So basically start with a little too long wire, and cut it down a little at the time while somehow measuring the effect. You should see an increase as you near the theoretical ideal length, and a decrease when you pass the practical ideal length which can vary a little. Then make a new wire at the peak length.

If you can, try using a solid core wire, instead of multi core. Also read up on the part of adding filter capacitors to the power supply near the receiver module.

I’ll try and follow up my post when I get the parts (and time) to actually build the field strength meter linked to in my post over in the other thread, and get some actual empirical data on this stuff.

@temp said:

you are using it with the atiny? Is it Vetter than rxb6 in your opinion?

attiny as filter? No the srx882 is connected to a arduino nano clone. Same as the rxb6 in this howto here.
I have also some rxb6 here. If I find some time , I will compare them both.

@magic-tune oft course arduino nano sorry my mistake

Got my 3400 kit today.

Only threw it together on a bread board, using antenna with dupont connector to the breadboard, sub-optimal length; and it picked up sensors I’ve never seen before, and they’re not mine… Might end up lowering the receivers voltage to cut down on traffic

Hopefully I’ll have time to make some quantifiable statements about the improvement, one day…

Info about my antennas:
For my main Homeduino receiver I use RXB6 as well and have no problems with reception with a single wire antenna from a pice of SatCable (there was another thread about details that I can not find now).

For other stations I use some china ship shit receiver and could not get any signal when using a single core wire from ~17cm.
But the coil antenna from http://www.elektor.nl/Uploads/Forum/Posts/How-to-make-a-Air-Cooled-433MHz-antenna.pdf and cut a little bit shorter, is working good for me with this modules!

Has anybody already tried those cheap 433MHz to USB Dongles from China which utilize TI’s CC1101 Chipset.
Like this one here: http://www.ebay.de/itm/1Stk-HC-11-USB-CC1101-433Mhz-Wireless-Transceiver-Modul-Neu-/181522242890?hash=item2a43919d4a:g:chcAAOSwq7JT~wGl

@magic-tune Hey magic-tune.

i have just switched from the cheap china senders to STX882 and SRX882.

but the rage is really really bad with this ones. only ~5 meters (sending and receiving).

any ideas?

@n3ro
Hey, for me they works great. I can remember one of my was also poor. The chip was different. wait…
crystal 13.2255 poor
crystal 13.2256 good

@magic-tune THX. i will check it

@magic-tune do you have the same with senders?

Yes ordert a set with 5 senders and 5 receivers. On my senders is a SF R433D Crystal. I use them in my 2xAAA-Attiny85-PIRs.