Simple, Inexpensive RF Modules

Hi all. So, in past projects I've sent data from remote sensors back to the base station using RF69 or LoRa radios. It has worked very well. But, now I'm working a project that requires a much simpler and less costly solution.

I just need to send a binary condition (i.e. 1/0, yes/no, open/close) from the remotes. I've seen forum posts from people using various cheap Chinese RF modules from eBay, etc. Some have had great success, others have struggled to get them working. So, I'm looking for devices recommendations from the former group.

Ideally, the solution would provide a single RX that could differentiate the signals coming from multiple (2 or 3) TXs and activate an individual I/O pin for each one. Maximum required range is 100 feet. Operation at 3.3V preferred.

Thanks for your help.

This did not offer at what frequency the values change.
I was thinking about having a couple dozen devices, sending back values, speed is not an issue.

please note if your values change rapidly, multiple times a second,
or of they change infrequently, once every couple hours....

If I may add to this question.

Is there a general limit of how many you can use ? (30 remotes ?)

The remotes will just be sending the status of PIR sensors. So, the changes are very slow - maximum say once a minute.

As I said, I only need 2 or 3 remote transmitters sending to (preferably) a single receiver that can determine which TX is sending and assert a corresponding I/O.

I've used the cheap RF nrf24lo1 modules: They work excellent and the code is easy to implement - using Robin2's tutorial.

Transmitting through wall/ceilings, it had to resend data a few times when I installed the receiver and transmitter 40 foot apart. If you plan on placing the module into sleep mode, it will likely kill the module; after further reading, I found the cause was due to the chip was not a true nordic chip.

So, I purchased these: which, not only are capable of going to sleep, but also advertised transmit up to 1000m.

JMeller:
So, I purchased these:

Thanks, but what are "these"? Part number? Web link?

NRF24L01

Tons available on Amazon.com; before purchasing, make sure it has the nordic chip.

edit: nordic

OK the, nRF24L01+ is one possible way to go. But even that is more capability than I need. I just need to send and on / off signal that doesn't change very often. I'm sure I've seen people post about RF TX / RX device pairs that just take a logic input at the TX side and produce the same logic output on the RX side. If I could find something that simple, I wouldn't even need a processor at my remotes. Just run the logic level from the sensor's output into the TX input.

At $9USD for 1000 meter pair or $12USD for a pack of 10 for the 50 meter, I'd guess you would pay nearly the same amount for limited capability you wish for.

True, but it means I'll need a processor at each remote. Anyway, an option to consider. Thanks.

gfvalvo:
True, but it means I'll need a processor at each remote. Anyway, an option to consider. Thanks.

is your origional premise incomplete ?
Are you really looking for an APPLICTION, not a part # ?
You want a remote switch to send on / off via rf to an receiver. at the lowest price for the remote ?
Just buy the wireless remote, with PIR, enclosure, battery holder and antenna from aliexppress for $8 free shipping

gfvalvo:
True, but it means I'll need a processor at each remote. Anyway, an option to consider. Thanks.

As this is an Arduino forum, I supect forum members assumed you were using one.

dave-in-nj:
is your origional premise incomplete ?
Are you really looking for an APPLICTION, not a part # ?
You want a remote switch to send on / off via rf to an receiver. at the lowest price for the remote ?
Just buy the wireless remote, with PIR, enclosure, battery holder and antenna from aliexppress for $8 free shipping

I tried to be clear, guess I wasn't. I'm looking for recommendation on the RF devices. The ideal setup would be:

  • A simple TX that takes a logic input and sends the state to the RX.

  • An RX that can listen to multiple TXs and set individual logic outputs based on the state received from the multiple TXs. These logic outputs would connect to digital inputs on my control processor (Teensy 3.2).

With that setup I wouldn't need to bother with a processor at each transmitter remote node. Just one processor at the receiver.

Hope that clears things up.

srnet:
As this is an Arduino forum, I supect forum members assumed you were using one.

See above.