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Simple RF M4 Receiver - Won't work from further than 4"
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Simple RF M4 Receiver - Won't work from further than 4"

by DPKJr on Sun Feb 14, 2021 2:08 pm

Hello,

I recently bought these items:
https://www.adafruit.com/product/1096
https://www.adafruit.com/product/1392
https://www.adafruit.com/product/1095

I don't know if the receiver is defective or if I am doing something wrong, but the receiver does not receive the signal if the buttons are more than 4" away.
I made sure that there was nothing around the receiver that would interfere with the signal.
This is unusable for my project, I need it to work at a much further distance.
Please help me figure out the problem.

I am attaching photos of my setup.

Thanking you in advance.
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Photo 1
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Photo 2
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Photo 3
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Re: Simple RF M4 Receiver - Won't work from further than 4"

by adafruit_support_bill on Sun Feb 14, 2021 2:23 pm

Try uncoiling the antenna. For best range it should be vertical and clear of other wiring.

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Re: Simple RF M4 Receiver - Won't work from further than 4"

by DPKJr on Sun Feb 14, 2021 2:44 pm

Thank you. It works up to 7 feet away now. Is that as far it will work? I need about 20 feet.
If there is another product that gets better distance please let me know.

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Re: Simple RF M4 Receiver - Won't work from further than 4"

by adafruit_support_bill on Sun Feb 14, 2021 2:55 pm

How long is the extended antenna wire? The ideal length for 315MHz is 23.81 cm (9.37 inch).

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Re: Simple RF M4 Receiver - Won't work from further than 4"

by DPKJr on Sun Feb 14, 2021 3:07 pm

It is right at 9 inches.
What should the range be?
If there is a better product please let me know.
I get frustrated when I push a button and nothing happens.
Thanks.

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Re: Simple RF M4 Receiver - Won't work from further than 4"

by adafruit_support_bill on Sun Feb 14, 2021 4:04 pm

For best reception the total antenna length on the receiver should be close to 1/4 wavelength - which for 315MHz is 9.37". With 9" of wire plus the length of the trace on the PCB, that should be just about perfect.

You should be able to get 20' if there are no obstructions or nearby RF interference. We can try replacing the keyfob transmitter. If you contact support@adafruit.com with a link to this thread we can get one out to you.

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Re: Simple RF M4 Receiver - Won't work from further than 4"

by DPKJr on Sun Feb 14, 2021 4:15 pm

These are the two fobs I have and they both get the same results, so I don't know if replacing them would do anything.
Let me know if there is a better product that I can buy, I don't mind spending more money to get something dependable.

https://www.adafruit.com/product/1392
https://www.adafruit.com/product/1095

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Re: Simple RF M4 Receiver - Won't work from further than 4"

by adafruit_support_bill on Sun Feb 14, 2021 4:34 pm

We have other wireless options, but they generally require some programming. What is the application?

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Re: Simple RF M4 Receiver - Won't work from further than 4"

by DPKJr on Sun Feb 14, 2021 4:57 pm

It is a ping pong scoreboard.
Each player bushes their button when they score a point and the app keeps track of the score and who should be serving and declares a winner.
Pic below.
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Re: Simple RF M4 Receiver - Won't work from further than 4"

by adafruit_support_bill on Mon Feb 15, 2021 7:56 am

There are the XBee radio modules. These will do up to 40 meters indoors.
We also have a number of 'Bluefruit' boards with Bluetooth LE. These have a range of about 35 feet.
If you have WiFi coverage, there is the ESP8266. We have these in various forms ranging from raw modules to breakout boards and Feathers.

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Re: Simple RF M4 Receiver - Won't work from further than 4"

by DPKJr on Mon Feb 15, 2021 10:54 am

Could you please recommend a particular XBee radio module.
Also please recommend key pobs/buttons I could use to signal it.

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Re: Simple RF M4 Receiver - Won't work from further than 4"

by adafruit_support_bill on Mon Feb 15, 2021 12:18 pm

If you can find some of the older Series 1 XBee modules, the simplest way to implement a remote control system is with line passing as described here: https://www.digi.com/blog/post/xbee-tec ... -with-xbee

The newer modules such as the Series 2 we currently stock use the Zigbee protocol which is more powerful, but a little more complicated to set up.
There is a tutorial here on interfacing XBee modules to the Pi: https://circuitdigest.com/microcontroll ... nterfacing

Any 'momentary' pushbutton will work. There are many styles and sizes available:
https://www.adafruit.com/?q=momentary+p ... =BestMatch

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Re: Simple RF M4 Receiver - Won't work from further than 4"

by DPKJr on Mon Feb 15, 2021 1:00 pm

Thank you.
I will research the links you sent more closely, but on first glance it looks like I would have to have a powered Xbee on both of the transmitting sides and on the single receiving side.
I was hoping to make the transmitting sides (player 1 and player 2 buttons) a portable battery operated device such as a key fob.
The receiving side will be more stationary with a power source.

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Re: Simple RF M4 Receiver - Won't work from further than 4"

by adafruit_support_bill on Mon Feb 15, 2021 2:04 pm

The XBees are relatively low power. You could run them from a small LiPo or coin cells. But the battery life would not be as long as something like the fob.

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Re: Simple RF M4 Receiver - Won't work from further than 4"

by pete_projects on Wed Mar 03, 2021 2:19 pm

I've run into a similar issue. One issue I've noticed is when I go beyond a certain distance (generally 5 to 10 feet), with LED's connected to the outputs they flicker. A photo of my setup is below.

With the device working correctly, the LED fully on, voltage across the LED is 1.84V.
When the LED is flickering, voltage across the LED is only at 0.06V to 0.28V (I haven't looked on a scope).

Is this an issue with the hardware? I haven't seen any mention of flickering with other forum questions.

These are what I'm using:
https://www.adafruit.com/product/1096 (Simple RF M4 Receiver - 315MHz Momentary Type) - supply voltage at 5.24V
https://www.adafruit.com/product/1095 (Keyfob 4-Button RF Remote Control)
https://www.adafruit.com/product/4204 (LEDs)

The range I'm hoping to get is at least 50', and it needs to be RF. Can you advise on other products that could work for this?

I see the XBEE suggestion earlier in the thread, I'm also wondering about this product. Could this be a better option to get a longer range?
https://www.adafruit.com/product/3177 (Adafruit Feather M0 RFM69HCW Packet Radio - 868 or 915 MHz - RadioFruit)

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