Extending doorbell to basement wirelessly using multiple 433 Mhz RF transmitters/receivers

Thread Starter

aacjto

Joined Jan 22, 2017
1
I tried two commercial wireless doorbell extenders, but neither was able to provide a signal that reached my basement family room. Distance isn't an issue, but their are many obstacles in the way such as floor, HVAC, plumbing and walls. Please let me know if you think my proposed solution will work. Or, do you have any other suggestions to solve my problem.

My first attempt was to look for a commercial RF extender but was unable to provide the supplier with a part number of the encryption chip used in the commercial doorbell extender, so they could not tell me if their RF extender would work with the existing doorbell extender. I've given up on this solution.

In general, my next proposed solution would consist of two receiver/transmitters. I would connect a 433 RF transmitter to the inside doorbell unit so that when someone presses the outside doorbell button, the inside doorbell unit still rings and the transmitter sends its signal. The first receiver is placed within range of the first transmitter. The signal to the first receiver then activates a second 433 RF transmitter. A second receiver is placed in the basement family room to activate a chime.

Does this solution sound feasible? Are there any issues that should be addressed in the final design, especially those related to RF circuits?

Here is a link to a transmitter/receiver combo at mouser.com.

Thanks in advance people willing to help.
 

ericgibbs

Joined Jan 29, 2010
9,136
hi aa,
The TXR in that link is a RS232 transmit/receive device, it is not really suitable for a bell extender.
There are 'analog' version of the 433mHz TX/RX modules.
E
 

LesJones

Joined Jan 8, 2017
2,420
It will not work. When the first receiver activates the second transmitter it will latch up as the first receiver will respond to the second transmitter. You could get round this problem by using different frequencies for each step in the link. Using cheap transmitters and receivers you would need widely spaced frequencies. (You would have to find frequencies that were legal to use in your country.) You would also need to ensure that the transmitters and receivers could cope with the type of modulation used by the door bells.

Les.
 

GopherT

Joined Nov 23, 2012
8,012
Working on LesJones concern, you could use an astable multivibrator (I.e. a "555 timer" connected as an astable "one-shot" timer). The trigger is "pulled" when the input transistions from high to low and the output goes high.

With that, you can rig up a trigger activator circuit on your first (current) wireless receiver. As the gues pushes the button, the first wireless bell activates, then, when the guest lifts their finger from the button, the first receiver stops and, at that point, the 555 (mounted on the first receiver bell) is activated (activates the second transmitter) and sends a signal to the second second bell.

The 555 output can directly power up to 250 mA so that is likely enough to drive the second transmitter directly.
 

MrSoftware

Joined Oct 29, 2013
1,619
They're are a few data over house power wire solutions commercially available. I use the ethernet over power wire adapters myself to reach rooms out of wifi range. Maybe you could easily adapt one of these for your purpose? Maybe there's an rs232 over power wire?
 
Top