This post is a guide for the popular RF 433MHz Transmitter/Receiver modules with Arduino. We’ll explain how they work and share an Arduino project example that you can apply to use in your own projects.
We have other tutorials about the 433MHz transmitter/receiver that you may found useful:
Throughout this tutorial we’ll be using the FS1000A transmitter and corresponding receiver, but the instructions provided also work with other 433MHz transmitter/receiver modules that work in a similar fashion. These RF modules are very popular among the Arduino tinkerers and are used on a wide variety of applications that require wireless control.
These modules are very cheap and you can use them with any microcontroller, whether it’s an Arduino, ESP8266, or ESP32.
Specifications RF 433MHz Receiver
Specifications RF 433MHz Transmitter
You can purchase these modules for just a few dollars. Click here to compare the RF 433MHz transmitter/receiver on several stores and find the best price.
In this section, we’ll build a simple example that sends a message from an Arduino to another Arduino board using 433 MHz. An Arduino board will be connected to a 433 MHz transmitter and will send the “Hello World!” message. The other Arduino board will be connected to a 433 MHz receiver to receive the messages.
You need the following components for this example:
You can use the preceding links or go directly to MakerAdvisor.com/tools to find all the parts for your projects at the best price!
The RadioHead library provides an easy way to work with the 433 MHz transmitter/receiver with the Arduino. Follow the next steps to install that library in the Arduino IDE:
The RadioHead library is great and it works with almost all RF modules in the market. You can read more about the RadioHead library here.
Wire the transmitter module to the Arduino by following the next schematic diagram.
Important: always check the pinout for the transmitter module you’re using. Usually, there are labels next to the pins. Alternatively, you can also take a look at your module’s datasheet.
Upload the following code to the Arduino board that will act as a transmitter. This is based on one of the examples provided by the RadioHead library.
#include #include // Not actually used but needed to compile RH_ASK driver; void setup() < Serial.begin(9600); // Debugging only if (!driver.init()) Serial.println("init failed"); >void loop()
First, include the RadioHead ASK library.
#include
This library needs the SPI library to work. So, you also need to include the SPI library.
#include
After that, create a RH_ASK object called driver .
In the setup(), initialize the RH_ASK object by using the init() method.
Serial.begin(9600); // Debugging only if (!driver.init()) Serial.println("init failed");In the loop() , we write and send our message. The message is saved on the msg variable. Please note that the message needs to be of type char.
const char *msg = "Hello World!";This message contains the “Hello World!” message, but you can send anything you want as long as it is in char format.
Finally, we send our message as follows:
driver.send((uint8_t *)msg, strlen(msg)); driver.waitPacketSent();The message is being sent every second, but you can adjust this delay time.
delay(1000);Wire the receiver module to another Arduino by following the next schematic diagram.
Important: always check the pinout for the transmitter module you’re using. Usually, there are labels next to the pins. Alternatively, you can also take a look at your module’s datasheet.
Upload the code below to the Arduino connected to the receiver. This is based on one of the examples provided by the RadioHead library.
#include #include // Not actualy used but needed to compile RH_ASK driver; void setup() < Serial.begin(9600); // Debugging only if (!driver.init()) Serial.println("init failed"); >void loop() < uint8_t buf[12]; uint8_t buflen = sizeof(buf); if (driver.recv(buf, &buflen)) // Non-blocking < int i; // Message with a good checksum received, dump it. Serial.print("Message: "); Serial.println((char*)buf); >> Similarly to the previous sketch, you start by including the necessary libraries:
#include #include
You create a RH_ASK object called driver :
RH_ASK driver;In the setup() , initialize the RH_ASK object.
void setup()< Serial.begin(9600); // Debugging only if (!driver.init()) Serial.println("init failed"); >In the loop() , we need to set a buffer that matches the size of the message we’ll receive. “Hello World!” has 12 characters. You should adjust the buffer size accordingly to the message you’ll receive (spaces and punctuation also count).
uint8_t buf[12]; uint8_t buflen = sizeof(buf);Then, check if you’ve received a valid message. If you receive a valid message, print it in the serial monitor.
if (driver.recv(buf, &buflen)) < int i; // Message with a good checksum received, dump it. Serial.print("Message: "); Serial.println((char*)buf); >In this project the transmitter is sending a message “Hello World!” to the receiver via RF. Those messages are being displayed in receiver’s serial monitor. The following figure shows what you should see in your Arduino IDE serial monitor.
You need to have some realistic expectations when using this module. They work very well when the receiver and transmitter are close to each other. If you separate them too far apart you’ll lose the communication. The communication range will vary. It depends on how much voltage you’re supplying to your transmitter module, RF noise in your environment, and if you’re using an external antenna.
If you want to use 433 MHz remote controls to communicate with your Arduino, follow this tutorial: Decode and Send 433 MHz RF Signals with Arduino.
If you are an Arduino beginner, we recommend following our Arduino Mini Course. It will help you quickly getting started with this amazing board (and it is free!).
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Thanks for reading.
January 19, 2019
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This really needs some actual range capability data: line of sight, through one interior wall (drywall with wood studs), same with metal studs, through one concrete block wall, etc. Reply
Yes you are right. Thamks for the comment John! ReplyHi! Nice and simple tutorial! I was looking for different options for Wireless COMM, and 433 MHz is the frequency I am most interested in. I have two questions: – On the serial communication with the transmitter/receiver, does it work with different data rates other than 9600? (Up to 115200 , for example). – Does each module work as both transmitter and receiver? By the pictures it seems that they only perform transmitting or receiving but not both. Thank you very much!
Javi Reply
You’re welcome Javier.
1) Yes, you can use any baudrate
2) No, they only perform one task. If you’re looking for a module that offers both Transmit and receive, you should search for this module nrf24l01. (You can use that module with he RadioHead library)
It’s a great module for wireless communication too. I’ll be posting a guide for that module in a couple of weeks. Reply
I picked up a couple of these on eBay a few months ago with a vague idea of testing their functionality, so this rather useful little guide is quite timely. Thank you. Reply
I’m glad you found it useful! Let me know how this tutorial works out for you.
Have a great day,
-Rui Reply
Yes, that’s true. All modules communicate at the same radio frequency 433MHz. So they’ll interfere with each other. but you can add if statements and verify if that message makes sense or not. I hope this helps! Reply
Good tute but I would have preferred one on cloning a garage remote…. Thanks anyway. 🙂 ReplyHi Louis, I have something similar here: https://randomnerdtutorials.com/arduino-control-220v-lamps-from-anywhere-in-the-world/
That’s where I clone a remote control. I hope this helps.
-Rui Reply
Hello Luis,
I was playing with some modules today, they work great as soon as you equip them with antennas… Then I found this: instructables.com/id/Decoding-and-sending-433MHz-RF-codes-with-Arduino-/ Reply
Yes, you can use with any microcontroller, but you have to write your own code or find a library for this module. Reply
Sanyaade AdekoyaCool project, I have some RF 433MHz Modules lying around. May be I should give a short during the weekend 🙂 Reply
Awesome! Let me know how it works out for you Sanyaade! ReplyHi dear Rui,
Really u r doing great job for those r new to arduino.
And am preparing second arduino by myself on the bredboard , I think it should work well, send some gsm based project using arduino.
Thanks,
Ramesh, india Reply
Many thanks Rui,
This is my first foray into RF transmition and found this instructable very useful.
I made up my own prototype boards for the NANO and had this running inside an hour (after spending two days making the proto boards). I now have a basic understanding of RF data transfer and am now looking at working out how to send command instructions via RF. I am currently testing different length antenae for these units and shall see if there is a marked difference in length and cable type. Lance. Reply
Hi Lance,
Awesome! I’m glad you found this guide useful.
It’s a great addition to those modules. Adding an antenna can increase greatly the distance that these modules can talk. Reply
Hi,
Thanks for sharing these excellent tutorials.
My experience with the receiver is to power it from 3.3 Volts , got better range. Maybe less noise ?
Do you have any plans for a tutorial based on Arduino and GSM module ? Like SIM900 ? Reply
Hi Nils,
Thanks for sharing your results. Right now I have to finish other projects first, but that module is definitely on my to-do list! Reply
Greawork and thank you very much! Very useful! I have a question regarding the ports to be used. How does the arduino board know where you have connected the receiver or transmitter too? Thanks again!! Reply
You can go to your device manager (if you’re on windows) and plug one of your Arduino boards. It will tell you which COM port it is using.
Then connect the other Arduino board to also check its COM port Reply
Hi, I did everything in you guide but get nothing in serial. Did the exact same setup and copied and pasted the code and still nothing. What could be the issue? Ive spent over 1 week and im still stuck, please help Reply
Hi Andrew,
I know that it can be frustrating not finding the issue. I’m not sure what it is based on what you’ve said….
It can be a problem with your Arduino, wire connections, copying and pasting the code.
Or a problem with a component that is defective… Reply
Hi, great tutorial. But my RF module communication seems unreliable and slow. What can I do to increase the range of these buggers and also have reliable communication? (I’m using arduino uno and nano)
thnx Reply
Add an antenna to the modules and make sure you are powering them with the max voltage they can handle. That will increase their range Reply
is the frequency variable or is it fixed Reply These modules always operate at 433MHz Reply chevalier pierreHello I used a DS18B20 to sense the temperature with Arduino
I use a 433mhz transmitter to send the temperature on my raspberry
the raspberry I have the receiver, and then I store the temperature in a database
if Arduino and raspberry are close (20 cm), no problem, I get the temperature
if I remove the raspberry Arduino, I get nothing
the transmitter and receiver antenna
can you help me ?
best regards Reply
Hello,
Connect a 17 cm antenna to both transmitter and receiver. This will improve range. Remember the datarate is only about 2000 bits/sec Reply
Thanx alot for this great ‘to the point’ guide!
A question:
Will the receiver work for ‘any’ messages sent on this frequency? I installed a firealarm that sends messages between the detectors at this frequency and these messages are not read as I expected but maybe they are of a different type? Reply
Hi, is it possible to check the signal strength by sending I.e. 100 packets and checking how many was received, thus 100% would be the effective strength. Reply
I think there’s already an example that shows the signal strength for these modules if you search for it, but I’m not 100% sure Reply
thanks. good example. can I use this transmitter receiver 433 MHz for continous signal like sine curve Reply
You should be able to use the transmitter to constantly send data, but I’m not sure what you mean by signal like sine curve Reply
thank for your collaboration. I need to send one signal like sine or cosine wave. and receive it on a separate arduino. can you help me on a program to apload on Arduino (transmiter and receiver) Reply
Bradley WaldenHi. great tutorial. I have two questions:
1. Would this work if I used one arduino connected to the receiver and this usb to serial connector attached to the transmitter (arduino.cc/en/Main/USBSerial)
2. Is there someway that I could make it work by connecting the receiver/transmitter modules to the RX/TX pins (pins0&1) on the arduino? Reply
You’ll actually need an Arduino connected to the transmitter. If you use an Arduino nano it also has serial capabilities and it’s smaller than an Arduino UNO Reply
Bradley WaldenHow would I be able to send signals from my computer through the serial monitor to the Arduino wirelessly Reply
Troy SchmidtSo I will of course try to figure it out,, but maybe I will struggle over a very common desire. I want to transmit joystick values over the 433 mhz unit, How to send various sensor data and decode it to various output?? Reply
I don’t have an example to that exact application. Thanks for asking,Hello Ruy thanks for great tutorial!
I have a question. I have two arduinos and I run the programs explained.
The output is “Hello World!” plus some garbage charactecters at the end (e.g. #).
I’ve tried to make the receiver buffer (uint8_t buf[12) smaller (or bigger), but the problem remains.
Any idea how to solve this?
Thanks Reply
Failure to null terminate the string. You can either send the null terminator over the rf channel (strlen(msg)+1), or add it on the receiver side as follows. void loop()
uint8_t buf[20];
uint8_t buflen = sizeof(buf)-1;
if (driver.recv(buf, &buflen)) // Non-blocking
buf[buflen] = 0; // null terminate string
// Message with a good checksum received, dump it.
Serial.print(“Message: “);
Serial.println((char*)buf);
>
> Reply
Hi
I’ve been trying to upload the receiver sketch and everytime it says “Stray /240 in program”
I copied it straight from your website. Please help Reply
Dear Rui, My module works with 5V, so please ignore my first post. I have another question: why is the reciever module data on digital pin 11 of the arduino? I see no declaration of this pin as input in the code. Would it work on digital pin 9 as well? The reason is that I would like to write the data to an SD card so I need the pin 11 for that. thank you for your support Sebas Thank you Reply
You can change the pins, but you need to read the documentation to do that and configure the pins with the library configuration Reply
Otto KlaasenHello Sir, to change the pin change following in the code for the transmitter: // RH_ASK driver;
// 2000=speed,2 = RX,4 = TX, 5 push to talk
RH_ASK driver(2000,2,4,5); // Pin4 = TX Connect your pin 4 to the transmitter module. For the receiver same: // RH_ASK driver;
// 2000=speed,2 = RX,4 = TX, 5 push to talk
RH_ASK driver(2000,2,4,5); // Pin4 = TX Connect pin 2 to the receiver module. Code has been tested with Arduino Nano, with ATTINY it did not work, had to use some other code with the manchester library. Kind Regards
Otto Klaasen Reply
Hello, i recieve
”
Message: Hello World!
Ď
”
with D below, please could you help me where is problem? I have same code as u. Reply
That’s awesome work
and I have one question to ask you about “Can they sending data in ‘float’ ?”
Because I’m use RF 433 mhz module to sending voltage value from analog pin but
they can’t receive it Reply
Yes, you should be able to send floats (or convert them to string), but I don’t have any tutorial on that specific subject Reply
Thanks a lot … ReplyI read your Complete Guide for RF 433MHz Transmitter/Receiver Module With Arduino. In the Transmitter Circuit it advises to Then upload the code below. But I cannot see any code to upload. Please advise where to find this code. Thanks
Rob Reply
Hi Rob.
The code is shown in the blog post.
However, if you’re having trouble seeing that, you can get the code in this link raw.githubusercontent.com/RuiSantosdotme/Random-Nerd-Tutorials/master/Projects/433MHz/transmitter.ino
I hope this helps 🙂 Reply
You can do that. But it is not recommended, since those pins are used by the Arduino when it uses serial communication (this means it uses those pins when you’re uploading code and when you use the serial monitor). If you really need to use those pins to receive data, you need to disconnect the connections on the TX and RX pins when you upload code.
Additionally, the library doesn’t use those pins by default. So, you also need to make some changes to the library code (which we don’t recommend). I hope this helps.
Regards,
Sara Reply
Hello Rui,
I couldn’t make it work. Receiver doesn’t get the messages. Do I need to do something
with pttPin pin? The doc says – “The pin that is connected to the transmitter controller. It will be set HIGH to enable the transmitter (unless pttInverted is true).” Do I need to set it to HIGH to enable transmission. What are the steps to debug the problem? How can I check if it is broken module, circuit or code? Reply
The modules are very inexpensive and sometimes they come broken. Can you grab another receiver and test to see if it’s working? Reply
Thank you for prompt reply. I will test it with another module. Is there way to check if it is receiver’s or transceiver’s issue? Or I have to try all permutations :)? Also what about this pttPin? Should I do something with it? Is there a way to test communication in one Arduino – for example connect Tx and Rx pins? Reply
thank you very much for this manual. helped a ton ! Reply Sara Santos You’re welcome! ReplyThanks for a great tutorial. I am sending some binary code from the transmitter to the receiver and it is coming through fine and printing to the serial monitor. However, I am having trouble saving that binary code to a int variable so I can use it with a conditional statement like the if statement. What am I missing here. John Reply
Hi John, I don’t have any examples on that exact subject, but if you search something like “convert binary to int Arduino”, you should be able to find an example similar to what you’re trying to do. Sorry I couldn’t offer much help for your specific problem. Regards,
Rui Reply
I’m getting a “No such directory found” error when verifying the code. It seems to be coming from the #include
#include libraries. I did add them like a usual… Any ideas where I messed up?? Thanks! Reply
Hi Casey.
Many of our readers have several versions of the Arduino IDE installed. If that is your case, please verify that you have the libraries installed in the right Arduino IDE version.
Regards,
Sara 🙂 Reply
Hey I’m a noob in this… I’m using an arduino pro mini I wanna know what should be the connections for transmitter circuit in arduino pro mini Reply
Sara SantosHi Chinmoy.
You can use the same connections.
Connect the data pin of the transmitter to Pin 12, GND to GND, and the power pin to VCC. Here’s the pinout for the Arduino Pro Mini, it might help: cdn.sparkfun.com/datasheets/Dev/Arduino/Boards/ProMini8MHzv1.pdf
Regards,
Sara Reply
hello sir
everything works fine but i am not receiving anything in my serial monitor
help me please
thanking you in advance Reply
Hi.
Are both Arduino boards running at the same time?
They need to be close to each other so that the receiver can get the transmitter messages.
Also, make sure that you have just the receiver board with the serial monitor opened.
Regards,
Sara Reply
Hi Umar.
The libray we use in this example, uses Pin 12 for the transceiver circuit and Pin 11 for the receiver circuit by default.
You can change that on the library file, if needed.
Regards,
Sara Reply
i follow tutorial and work well, but I don’t see where you configure the pin 12 in transmitter and where you configure pin 11 in recever. it is because is already configure in radiohead libraries or something else thanks Reply
Sara Santos Hi.an absolute “green pea” question, I want to run a dc motor with a “hold to run” foot pedal switch, the motor stops when the foot pedal switch is released. the distance from the transmitter to the receiver is no more than 6′,; what do I need to do this? Reply
Sara SantosHi Barney.
Have you taken a look at the Arduino debounce sketch example?
I think it might help. The example turns on an LED while the button is pressed. Instead of turning the LED on, send a message to the RF transmitter. When the button is not being pressed send a different message to make the motor stop.
You can access the debounce sketch example in your Arduino IDE under File > Examples > 02.Digital > Debounce
Let me know if you need further help.
Regards,
Sara Reply
Hi,
I noticed that in the transmitter, port 12 was used for the signal output. But it does not appear in the codes. Was it the right code?
Appreciate your comments. Thank you. Reply
Hey guys, Thank you very much for sharing
I have a question for you: I tried to create a similar project but using either a ESP32 or NODEMCU8266 instead of Arduino Uno or Nano. The problem is that none of the message transmitting libraries work with those processors (VirtualWire, Radiohead). Any idea on how can make the ESP32 talk to a Nano through 433Mhz Tx/Rx ? Thanks! Reply
Hi — GREAT tutorial. However, I have a problem. I want to use the Arduino 433MHz and 315MHz pair for a pair of walkie-talkies and want to power the receivers all the time. They work fine (actually hi-fi audio up to 10 kHz since I’m using PWM modulation, but change the Rx comparator to an LM393 for faster switching) but the Rx modules oscillate when powered but without a received signal. Can anything be done to remedy this? Thank you in advance. Reply
paulo lima Hi.Hi Paulo, If you do an online search for the Radiohead library, it’s in there.
When I use it I have to include radiohead then delete what I don’t need. Bill Reply
Need to use Library RadioHead – 1.84
I spent many hours trying to debug this using the SparkFun RadioHead library and it doesn’t work with that library version. Reply
Absolutely no explanation whatsoever of why pins 11 and 12 are used nor any explanation on where to go for more information regarding pin choice. Your tutorials are incredible; this is sub-standard for your normal quality of work. Reply
Sara SantosHi Michael.
You are right.
This tutorial is a little bit outdated.
It uses those pins because those are the default pins used by the library.
Regards,
Sara Reply
ola, preciso trocar informações entre 2 esp32. Esse código esta dando erro ao compilar… Serve pro esp32? Reply
Sara Santos Este código é para Arduino.I’m pretty in awe of the fact that you’ve literally taken the example code from RadioHead/examples/ask/ask_receiver/ask_receiver.pde, and
RadioHead/examples/ask/ask_transmitter/ask_transmitter.pde
and not cited these files at all. Sure you’ve added some explanation, but you did not write those examples, and it is very dishonest of you to not give credit to the library authors in this instance. Reply
Hi Bill.
I’m really sorry about that.
This was one of our very first tutorials. Back from 2013.
We were still learning the best way to share content at the time.
That detail was missing. I’ve fixed that.
Thanks for pointing that out.
All our recent tutorials have links to their references.
Regards,
Sara Reply
There are also plenty of people asking about how to change the designated pins and your response is about “modifying the library”, why on earth would you tell people to do that? RH_ASK(uint16_t speed = 2000, uint8_t rxPin = 11, uint8_t txPin = 12, uint8_t pttPin = 10, bool pttInverted = false);
The constructor for RH_ASK offers the correct way to configure input and output pins Reply
Hi, how to invoke the constructor with my own speed and pins? Could you make an example please? Actually I was searching for a comment like yours but I still don’t get how to call with the constructor without modify the source code of the library Reply
can i use the receiver without an arduino? ReplyDo you need to use the digital pin shown as I am using this in conjunction with a TFT screen shield and the pins are already used. Reply
Hi, how to invoke the constructor with my own speed and pins? Could you make an example please? Actually I was searching for a comment like yours but I still don’t get how to call with the constructor without modify the source code of the library Reply
RAJA REDDYSir the aurdino board only transmits when it is connected to a computer or a laptop. What should we do if we want to transmit the signal from aurdino when it is connected to a power source like battery? Reply
Sara SantosHi.
Make sure you’re powering the Arduino properly.
After that, press the on-board RESET button to restart the board.
Regards,
Sara Reply
so you are missing something, for me it works without computer.
be sure to connect the battery to the correct place and supply the needed power to the board. Reply
Really good tutorial, thanks If I understood right, the RH library by default prepare both pins (tx and rx pins), so, In the arduino which is transmitting, what happened if I connect something in the rx pin?
I mean, if I am transmitting I will use the tx pin only, it could be useful if I can tell the RH library to do not use the rx pin because I will not use in this arduino, just in the other one with receiver part
Is it possible to setup RH library to use only tx pin in transmitter and only rx pin in receiver in order to let free as much pins as possible?
Thanks Reply
Disculpa bro una pregunta
estas librerias tambien puedo utilizar para poder controlar un servo o me podria causar problemas de complilacion ? Reply
Grateful for your tutorial. Tried several others without success. Yours worked first time. Newbie question “int i” in void loop() – I can’t see where “i” is used? Reply
Sara SantosHi.
You can remove that variable declaration.
It’s not used in the code. It’s a bug. We’ll fix that.
Thanks for pointing that out.
Regards,
Sara Reply
Hi.
I have been trying to get this tutorial to work for weeks now with no success. I am on my third set of modules, the first two were cheapies from Ebay and when they did not work I purchased some better quality ones from Rapid Electronics and these came with a datasheet. I am using a QUASAR QAM-TX2-433 transmitter and a RF SOLUTIONS AM-RX9-433P receiver. The sketches I copied and pasted into the IDE from your example and made one alteration in the Void Setup. I have included the statement ‘ else Serial.println(” init passed “); ‘ so that I am not left with a blank serial monitor. It appears that the setup is completing okay in both cases. The connections are made as per the datasheet (my receiver module has eight pins and all have been connected. I have also re-installed the Radiohead library, 1.121 the only one I could find, and Arduino SPI library from the Include Library folder. I am using Arduino Uno 1.8.19. I don’t know what else I can do. Difficult question but do you have any suggestions please? Thank you in advance.
Bob May Reply
Hi.
Thank you for getting back to me. The problem is that I don’t think the transmitters are transmitting or that the receivers are not receiving. I have included Bitmap images of the sketches and serial monitor outputs of the modules. I have 2 x RX470C-V01 pairs of modules from Ebay and a QUASAR UK QAM-TX2-433 miniature AM transmitter and a RF Solutions AM-RX9-433P Receiver Super Het AM 433MHz SIL 5V receiver from Rapid Electronics. They all give exactly the same output. I am using the 5V supply from 2 x Arduino Unos. I have used several different sketches from other websites and none were successful. Maybe you can come up with a solution.
Thank you again.
Bob May Reply
Hi.
These things are very difficult to troubleshoot.
Are you sure you’re connecting your modules correctly?
Regards,
Sara Reply
Hi, thank you for your help. So much for the “Easy to use, ideal for hobbyists” claim that the manufactures are making. I have spent months off and on trying to get these things to work with no success.
Anyway, I have checked, double checked and triple checked the connections and they are correct.
The receiver output on the serial monitor is “Message: □”. I have also been using the Arduino oscillator and the output on the transmitter side is a saw-tooth wave starting at 0v rising to about 500mv, and on the receiver side more of a sine wave the bottom at about 500mv and the top at about 1.5v. These measurements are taken from the Arduino A0 to the data pins on the modules.
I hope this information can help.
Thank you again.
Bob May
I have connected both the transmitter and Receiver modules on to one Arduino UNO and upload this code. I doesn’t get anything on the Serial Monitor. Please Help. Where is the issue. // Include RadioHead ASK Library
#include
// Include dependant SPI Library
#include // Create Amplitude Shift Keying Object
RH_ASK driver; void setup()
// Setup Serial Monitor
Serial.begin(9600);
if (!driver.init())
Serial.println(“init failed”);
> void loop()
// Set buffer to size of expected message
uint8_t buf[5];
uint8_t buflen = sizeof(buf); // Send a message to receiver
const char *msg = “Hello”;
driver.send((uint8_t *)msg, strlen(msg));
driver.waitPacketSent();
delay(2000); // Check if received packet is correct size
if (driver.recv(buf, &buflen))
int i;
// Message with a good checksum received, dump it.
Serial.print(“Received: “);
Serial.println((char*)buf);
> >
Hello Rui ;
Is there anyway to read door contact status using a ring wireless door contact without using a ring hub? Reply
Hi all
Very good tutorial I tried to compile on arduino board after installed radiohead library
but i catched that message C:\Program Files (x86)\Arduino\libraries\RadioHead/RadioHead.h:618:12: fatal error: util/atomic.h: No such file or directory Please help Reply
In fact the Radiohead library seems to be supported only on Arduino uno and not on ESP32?
please confirm Reply
Hi, I would like to know whether I can use this module for multiple tasks. I want to get data from multiple different sensors in the transiver and get different outputs according to those inputs in receiver side. I am using Arduino pro mini on both sides. For example If an MPU-6050 module tilted to right side a red led should light up and when tilted to left a yellow led should light up. Reply
If you give each data its own code, you can decode it in the receiver. For example up and down etc etc But a number works easier. Reply
Dave CrossFirst of all, thanks for all the very well documented projects! I have set up the transmitter on a Nano and receiver on a Mega 1280. When transmitting the receiver serial monitor display the expected message but also continues to print mostliy “U” until the line fills then starts again. Message: Hello World! 2UUUUUUUUUUUUUUUUUUUUUUIUUUUUUUUUUUU…
Message: Hello World! 2UUUUUUUUUUUUUUUUUUUUUUULUUUUUUUUUU… The transmitter and receiver are a couple of TWS-434A and RWS-434 modules I have had for years. Any thoughts would be appreciated. Reply
I do receive the “Hello World!” message in the serial monitor but it is followed by a series of characters that continue for several seconds before the next HW message displays. Message: Hello World! 2UUUUUUUUUUUUUUUUUUUUUUUIUUUUUUUU…
Message: Hello World! 2UUUUUUUUUUUUUUUUUUUUUUUULUUUUUU….
Message: Hello World! 2UUUUUUUUUUUUUUFUUUUUUUUUUUUIUUUU… The transmitter is a TWS-434a on a Nano and a RWS-434 RF receiver on a 1208 Mega.
Any thoughts? Reply
