15 push button RF transmitters to one receiver

hi
i need a simple method to transmit 15 digital High or Low signal. one receiver to get that ON/OFF signal. all transmitters and receiver is inside a distance 80m. i fount this

with there 4 button RF remote

is there some other receiver module that could receive about 15 inputs ???????

or any other simple method to get 15 ON/OFF signals transmitted to a receiver

Thank you

What are you trying to achieve?
Is the aim to send 1 of 15 signals or any combination of 15 signals?

Simplest way would buy 4 of those transmitter/receivers. Maybe just nees to check range.

Alternative is to get two Arduinos or similar with transceivers and build the 15 buttons circuit plus all coding. Not going into detail as I don't know exactly what's for and if you are keen to build it yourself.

"transmit 15 digital High or Low signal. one receiver to get that ON/OFF signal. all transmitters and receiver is inside a distance 80m."

Sounds like you have 15 transmitters and one receiver. Each transmitter has a switch and the receiver needs to know which transmitters have their switch ON and which have their switch OFF. Is that right? How quickly does the receiver need to know of changes at the transmitter?

That simple one-bit (OOK or On-Off Keying) receiver is not very suitable for multiple transmitters. All it does is detect the 315 MHz carrier. The transmitters are either ON or OFF (transmitting carrier or not). Two transmitters sending at the same time will interfere. The receiver is also prone to picking up noise when no transmitter is sending. To send any information, the transmitters have to send a series of pulses that the receiver can recognize to distinguish signal from noise. Since the transmission is one-way and prone to error the transmitters must repeat the messages to insure that they are eventually received.

My first guess at a viable solution would be a mesh network like this: https://tmrh20.github.io/RF24Mesh/

If more than one transmitter is on at once on a single frequency the signal at the receiver will be corrupted and unusable.

If you wish to acheive this each trnasmitter must have an associated receiver and be invited to transmit individually - ie 'polling'.

hence the single receiving point must also have a transmitter to tell each remote transmitter to say whether it's on or off.

regards

Allan

Those keyfobs transmit four different codes when one of the four buttons is pressed.
The keyfobs I have opened could be changed to another set of four codes (don't know this one).

If you use a receiver without decoder chip (not that Adafruit one), and an Arduino with e.g. the RCswitch library, then you can receive the individual code numbers and act opon it.
So 15 toggle buttons or 15 on and 15 off buttons should not be a problem.

You might get 5-10 meters with a short wire on the receiver.
You might even get 30 meters with a better aerial on the receiver.
80 meters with keyfobs? Dunno.
Leo..

I've gotten 175meters with the keyfob line of sight and monopole ant on receiver. The fobs get 12V so work quite well

sorry for not explaining my situation properly.

I am making a line following robot for my collage project. the task is that the robot needs to pick up a box form one of 16 points (loading area) and line follow back and unload it at specific location(unloading area).

at the start the robot is placed on the unloading area. 16 push buttons are placed on each loading area. when a push button is pressed the robot navigates its way to that location, picks up the box, navigates back to the unloading area, unload the box and waits for the next button to be pressed.
the complication between 16 push buttons and the robot needs to be wireless. i have built line following robots before but have no experience with wireless communication.

that's why I'm looking for a 16 transmitter 1 receiver configuration.
@johnwasser i don't need communication across all 16 points like in mesh network. i just need a simple one-way communication from transmitters to a receiver.

any advice is appreciated.
Thank you all

In that case, you're not worried about simultaneous button presses. You can also turn off receiving until it has finished the previous routine.
The key fobs would work, you won't save any money making your own with a microcontroller, RF transmitter module, battery, button, antenna. 15 of them, you'd solder a few jumpers, good to go on the transmission side.
For receiving, you can't use just one of those with the 2272 chip. You should use a basic rf receiver module just with vcc, gnd, and data pins. This will read all incoming signals instead of being paired to any one keyfob setting.

Can the 16 push buttons be wired to a single transmitter?

johnwasser:
Can the 16 push buttons be wired to a single transmitter?

Good question. If the area is small enough to just run button wires out to each of the 15 'loading areas', then you can just use 1 transmitter. Long input wires have their own problems so it doesn't scale, so you should clarify the distances and project aims. I.e., are you supposed to demonstrate this in a tiny tabletop or actual rooms up a hallway, etc.

The demonstration is in a long hallway. 'loading areas' are placed 4m apart from each other. the shortest distance from '1st loading area' to the 'unloading area' is 10m. longest distance from the '16th loading area' to the 'unloading area' is about 70m.
i could wire the 16 push buttons together. but there will be lot of wires and it wont look good....

or is there any other wire less technologies that i should look into other than RF for this application...

thanks for the support :slight_smile: :slight_smile:

arduino_x:
I don't see multiple adafruit modules working for this.

The linked page says this:

With that system you can't have 16 locations A-P, but only 4 each of A-D. 4 modules on your Arduino will mean 4x pins responding to button A, 4 to B etc.

Already been covered. Transmitters are fine, needs a plain non-encoded receiver.

SC2262 / SC2272 can transmit / receive 4 bits which is 16 states.
Normally however most of the key fobs just use 4 of the 16 states.
Something like 2 X 74HC148 cascaded as a 16 to 4 line encoder connected to SC2262 connected to 433 Mhz transmitter, and 433 Mhz receiver connected to SC2272 with 4 bit output connected to 74HC4514 as 4 to 16 decoder should get close to what you need.
Do you need latching outputs or momentary outputs.

mauried:
SC2262 / SC2272 can transmit / receive 4 bits which is 16 states.
Normally however most of the key fobs just use 4 of the 16 states.
Something like 2 X 74HC148 cascaded as a 16 to 4 line encoder connected to SC2262 connected to 433 Mhz transmitter, and 433 Mhz receiver connected to SC2272 with 4 bit output connected to 74HC4514 as 4 to 16 decoder should get close to what you need.
Do you need latching outputs or momentary outputs.

There is literally no reason to use an SC2272 on the receive side. A plain receiver will read out every single code regardless of transmitter with the RCSwitch library.

Only that unmodded combo is limited to four buttons.

Don't know how the chip in that keyfob is connected, but with a bit of hacking you should have access to at least six tri-state address pins and two address/data pins. 6^3 * 4 = 2916 different 4-button keyfobs possible.

The Adafruit receiver/decoders have address solder jumpers, so different combos can be used.
But it's easier to use one decoder-less receiver on the Arduino, and do the decoding in software.

Still not sure about the distance of those keyfobs.
Adafruit page mentions 25feet, but that's likely with the coil aerial on the receiver.
Leo..

nipzMegaMind:
The demonstration is in a long hallway.

is there any other wire less technologies that i should look into other than RF for this application...

If you have line-of-sight down the long hall then IR might work as well as RF.