Hello everyone,
i would like to discuss possible aplications of the cheap 433MHz or simmilar radio transmitters for remote control.
eg.: RF 433mhz Transmitter and Receiver Link Kit for Arduino/arm/mcu WL for sale online | eBay
Primarily remote control for say planes, cars, etc. Looking at the specifications, these transmitters appear to be capable of sending data at 2000bps. So i'm guessing that would probably be enough for transmitting 4 or more analogRead values. However, i cant find these sort of applications done by anyone, other than those that control garage doors etc. Am i missing something here? Could anyone shed some light into this matter. I would not like tu use Xbee or simmilar transmiter simply because they are too expensive.
To my understanding, i could use the above mentioned 433 MHz transmitter to send a string of data using one arduino hoocked to a transmitter, read the string with another Arduino hoocked to a receiver and manipulate the received data as i see fit for radio control.
Thank You for the replies.
Those are the cheapest modules available.
The VirtualWire library gets the most out of them.
http://www.airspayce.com/mikem/arduino/
(don't invert the signal (RX and TX use normal signals) and the ptt pin is not used.)
2000bps is 2000 bits per second. It is the baudrate.
The VirtualWire uses overhead, so it is perhaps 100 bytes per second.
For 433MHz the regulations require that a transmittor may only be transmitting during 10% of the time. Now you have only 10 bytes per second.
Also the range of those modules is limited. About 20 meters with an antenna.
They can be used to transmit a remote temperature sensor and so.
The receiver uses a tuned coil for the 433MHz frequency. Better receivers use a crystal. For good communication, you could take a look at CC1101 modules.
There are slightly better quality, but still very inexpensive 434MHz OOK/ASK parts. I have some of these that I am pretty happy with:
I have successfully used these at ~100m in a forested rural (low interference) setting.
How about these ones? Also seem pretty cheap...
http://www.ebay.co.uk/itm/2-pcs-NRF24L01-2-4GHz-Wireless-Transceiver-Module-SI24R1-for-microcontroller-/231020296733?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item35c9e1fa1d
I made my robot using this and i control with two joysticks sending 4 variable(two for the tries and two for the head with thew camera). They work well but i have problems with the distance, i only have 20 meters without obstacles.
I making a tutorial about how to used it and how to send multiple variables. It will be in my blog very soon controlrobotics.rodrigomompo.com
Most of the small cheap radios are range limited because of the way they work.
The transmitters are power limited and the receivers are broadband.
This allows them to be used very easily, to be able to cope with multiple data rates
and makes them ideal for short range applications like garage door openers etc.
The 2.4 Ghz radios wont penetrate solid objects very well, and the 433 Mhz radios are too low powered
to get any decent range.
You could theoretically get to around 1 Km with high efficiency gain antennas at both ends, but thats not really
viable for model control.
You can look into these
http://yourduino.com/sunshop2/index.php?l=product_detail&p=190
SPI to nRF24L01+ with power amp for increased range.
Little more than straight 433 MHz units but still less than xbees.
Also these
433mhz rf module are cheap and very easy to use,xbee instead is a tough option.
check this link if you want to make a 433mhz fr link.
http://embeddedsystem1.blogspot.in/search/label/decoder