433MHz is a license-free area of the RF spectrum in many countries. It tends to be restricted to low power and bandwidth but allows simple modulation schemes making it popular for low cost / bandwidth applications such as keyless entry and alarm systems.

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How to implement TDMA with basic 433MHz transmitter receiver pairs ?

Is it possible to use TDMA or some kind of time synchronization / psuedo random coding for a number of transmitters so that they can be interfaced with a single master receiver without jamming?
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47 views

How to interface multiple RF transmitters with single RF reciever?

How do I receive multiple signals simultaneously at a single receiver (433MHz) with multiple transmitters ? I am working on a polling system. This one is similar to the audience poll system using ...
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2answers
92 views

Using 433 MHz Tx/Rx without encoders/decoders

I want to use Tx & Rx Modules of 433 MHz standard modules you find everywhere. I just want Tx module powered up and Rx module should respond (probably key press) on Tx module. I don't have any ...
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2answers
169 views

RF Receiver for 433mhz and 315mhz?

I have a XD-RF-5V receiver wired to my Raspberry Pi listening with RFSniffer (433Utils). I also have a XD-FST 433.92mhz transmitter wired to my Raspberry Pi running codesend (433Utils). I can ...
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55 views

433 Mhz + Attiny85 improve range

I want to send information from my Attiny85 to my Raspberry. For the moment. Attiny and Emitter work on 5V Emitter have a 433 Mhz 1/2 waveform antenna I'am using virtual wire Raspberry receiver work ...
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113 views

433mhz micro directional antenna design

I'm trying to build a Radio wave penetration device that register the RSSI on the RX module. There are two 433 transceivers one is the RX and the other TX - I want to place between them different ...
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1answer
121 views

433Mhz Receiver Low Range Only on Raspberry Pi

I have an Arduino mini pro with a 433mhz receiver attached. I connected this to my computer via a usb to serial cable. I've tried it on two laptops ans it works fine with it (>15 metres), but when ...
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1answer
107 views

13MHz ISM band vs 433MHz ISM band

Would 14 MHz ISM Worldwide band have superior range and penetration (equal tx power)capability than the 433 MHz band? In that case, why aren't any transceivers made for this band? My application is ...
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58 views

Sub-1 GHz Narrow Band vs Wide Band

As per the TI document I came across which compares narrow band sub-1 usage vs wide band sub-1 usage mentions a concept called coding gain and its disadvantages. Because of my lack of understanding ...
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1answer
35 views

Wifi Channel vs a Sub 1 GHz channel of same width

If the same channel-width is allocated for a WiFi channel and also for a Sub-1 GHz channel, would the maximum allowable speed be the same for both channels theoretically? If they differ, what is the ...
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1answer
94 views

channel seperated communication in RF

In RF communication the carriers such as 950MHz, 133MHz are available under 1 GHz. If there are 50 devices using the for example 433MHz carrier, then how could large number of devices talk to each ...
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65 views

Sub 1GHz 433-MHz Band simultaneous channel usage

I live in Asia and I intend to use the Sub 1 GHz 433-MHz Band for a project. Before I proceed I wish to state I am using a combination of TI products CC1120 with a CC1190 to achieve more range. ...
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152 views

How does this electronic wall switch work with only a 2 wire circuit.

This is an RF wall switch but it uses only LIVE + LOAD1 cables like in the wall lamp switch (2 wires wall switch, load and live) If you short LIVE and LOAD the lamp turns on LIVE ...
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2answers
58 views

Antenna efficiency and PCB impact

I'm trying to improve the range on my 433 MHz radios and came across http://www.att.com/edo/en_US/pdf/AntennaFundamentals.pdf. (Geez, there's so much RF information in many bits and pieces, if only ...
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68 views

PCB ground shields

I'm trying to maximize the range on my 433 MHz radios and came across this article by TI: http://www.ti.com/lit/an/swra367a/swra367a.pdf. In section 3.5, they specify that your ground plane should be ...
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1answer
78 views

Improving RF sensitivity

I'm trying to improve the range on my 433 MHz radios that are using the CC430F5137. Based on 25.3.3 in http://www.ti.com/lit/ug/slau259e/slau259e.pdf, it seems like decreasing the RX filter BW can ...
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4answers
3k views

Wireless Home Automation 2.4GHz versus 433MHz [closed]

Project specifications To make some things clear first(wow that sounds so arrogant): This is an Arduino project This is supposed to be internationally applicable I have experience with 433 MHz ...
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3answers
2k views

What will it take to build a DIY 2km (city conditions) RF transmitter (433Mhz)?

This is my first question on this site. I am not an electronics/electrical engineer so pardon my depth of knowledge. I am trying to build an RF transmitter/receiver. These are my end goals : a text ...
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1answer
98 views

Two different length antennas can cause problems?

I am using two 443 MHz transceivers (FY-605 transceiver) with both having different antenna lengths. One antenna is around 12cm long and the other antenna is around 17cm long. Will this cause ...
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1answer
4k views

433MHz quarter-wave length antenna: longer is better?

I am trying to conduct an RF project using XY-MK-5V / XY-FS modules: link here My problem is that even though most blogs and Google searches for these modules use a quarter-wave length antenna ...
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0answers
69 views

Remotely Toggle Relay

A while back I decided I wanted to get into electronics, after which I bought a number of components to get me started, along with the Raspberry Pi and breadboard I already had. I am now wanting to do ...
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1answer
361 views

Arduino 433MHz transmission fails if falling edge is less than 122ms

I am trying to control a LED using a high-power 433MHz transmitter receiver pair, with transmitter connected to my Arduino Nano. Here is the transmitter (XLPCF20): ...
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3answers
496 views

Boost DC voltage converter for wireless temperature sensor (1.5V to 5V)

I'm trying to design a wireless temperature sensor powered by one (or maybe two) rechargeable NiMH AA cell(s). The sensor should read and transmit the temperature every couple of seconds and remain in ...
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1answer
303 views

Cloning Keeloq remote keyless entry system

Our house and a few other share the same gate, which is opened remotely by a 433Mhz transmitter. Unfortunately, we only get one remote per house, and we have two car. The company operating the gate ...
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2answers
719 views

433MHz RF transmission only working when holding usb cable in the air

I'm really puzzled about this. I have a simple transmission between two ATTiny85's going on with a 433MHz receiver and transmitter. The transmitter is in the basement so the signal is rather weak but ...
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2answers
2k views

Attiny85 hardware interrupt unreliable, 433 MHz remote

SCROLL DOWN TO SEE THE SOLUTION (UPDATE II) ORIGINAL POST: I am currently building a 433MHz remote with two buttons. The remote is controlled by an Attiny85v(8MHz). Sadly it does not work very ...
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3answers
8k views

Boost 433MHz receiver module receiving signal (XY-MK-5V)

I am using some "no-name" (In Fact "XY-MK-5V" stands on the board) 433MHz receiver (and transmitter) on an Arduino project. I can receive the signals sent from my other Arduino very good (it sends ...
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4answers
4k views

More transmit power for 433MHz transmitter module by increasing voltage

I am using these 433MHz modules. According to the product information, I can supply the transmitter from 3-12 Volts. I am sending the data from an arduino (5V data) and want to power the transmitter ...
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1answer
324 views

433MHz sender/receiver modules share antenna

I am using a sender and a receiver for the 433MHz band, looking like these. Is it possible to share the send and receive antenna and attach one good instead of two wire antennas?
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1answer
1k views

Transmit and receive 433,92MHz signal from the smartphone [closed]

I would like to use my smartphone to send and receive signals from the devices that is working on the 433,92MHz. I assume that it's not possible to communicate directly with this device from the ...
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2answers
315 views

Thermostat bypass wiring [closed]

I'm trying to bypass the heaters thermostat of my apartment and having only a small knowledge of electronics I would like to have a some help with it. Forgive me for the ugly paint schema but I ...
3
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1answer
4k views

How to check a 433Mhz module on an Arduino

I am new to arduino and electronics so please bear with me :) I would like to build a 433 MHz receiver which output I would later feed to a RPi (that will be the easier part for me). I bought a set ...
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1answer
1k views

433MHz Module Antenna Ground

I have these common ebay 433 module pairs pictured below And trying to hook up external antenna. On the TX there is a little hole marked ANT which works for that. On the RX pictured (XD-RF-5V) there ...
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1answer
849 views

Can I use this rf module with HT12E and HT12D?

I have recently made RC car using HT12E and HT12D connected to a cheap ASK RF module of 433 MHz frequency,but it's range is not good only a few meters and also so prone to electrical noise generated ...
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4answers
1k views

How to reduce motor electrical noise?

I have made RC car using using ht12e and ht12d, two geared DC motors, RF module. Now my problem is that when motor starts rotating, it is generating some kind of RF signals which are interfering with ...
3
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1answer
434 views

Detached antenna and connecting wire length

Since my this particular question didn't get any answer, I thought of asking a more focused question, along a path which seems a bit more feasible after few tests. Is it possible to install the ...
2
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1answer
1k views

Transmission via RF433Hz Transmitter/Receiver pair failing AVR

I am trying to send data wirelessly through a RF433Hz receiver/transmitter pair, but nothing seems to want to work.I want to the transmitter to continuously send a number (0x81) to the receiver when I ...
2
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1answer
1k views

Preventing Interference when using RF transmitters and receivers

I want to use a "listen-before-talk" approach to transmit data from sensors connected to a transmitter and receiver pair to a MCU connected to a transmitter and receiver, which means that the sensor ...
7
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1answer
3k views

Why is 433 MHz still used?

The new RF frequencies are 868 MHz for Europe and 915 MHz for the US. I heard 433 MHz is barely regulated, read: it's chaos. Then why are 433 MHz RF modules still used? Are they cheaper to produce?
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2answers
533 views

Active 433Mhz RF tag battery life question

I am exploring the world of RTLS system and trying to produce one on my own. I chose 433Mhz frequency for its penetration capabilities and I produced a PCB mounting CC430 TI family MCU-transceiver, ...
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2answers
2k views

How do I change the frequency of an rf module?

I recently bought an AM radio transmitter/receiver from eBay. It was only after I bought it, however, that I noticed that the frequency was 315/433 MHz. I live in the UK so only 433 MHz would be ...
4
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1answer
2k views

Can anyone identify this 433Mhz OOK protocol?

I am working with some wireless devices that use 433MHz OOK transmitters and receivers. They use a simple protocol for the data sent between the nodes. I feel it is reminiscent of common IR remote ...
2
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1answer
882 views

433Mhz Receiver

I'd like to build from scratch a 433Mhz receiver. Can anyone point me to a schematic or some material to learn how to build one? Google search didn't come up with much in the way of building one from ...
7
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3answers
5k views

Improve range of 433MHz RF link

I have a system comprised of a wireless sensor which transmits temperature readings to a main base. The wireless sensor system is made up of: 12F683 pic to take the temperature reading (manchester ...