Shop OBEX P1 Docs P2 Docs Learn Events
RFM12 - cheap wireless transceiver — Parallax Forums

RFM12 - cheap wireless transceiver

Robot FreakRobot Freak Posts: 168
edited 2009-06-08 22:17 in Propeller 1
Hello,

Just found the RFM12 wireless transceiver on the internet, it comes in a nice little package with all the necessary hardware.
It has an SPI interface, and runs on 2.2V - 5.4V power supply.

Seems to be an interesting module to connect to the Propeller!
I ordered 5 of them, does anybody have experience with these modules?

Kind regards,
Robot Freak

www.hoperf.com/pro/rfm12.html
www.embedds.com/interfacing-rfm12-transceiver-module/
ideetron.biedmeer.nl/Webwinkel-Product-186674/FSK-zendontvangermodule-met-SPI-interface-DIL.html (Dutch distributor)

Comments

  • Oldbitcollector (Jeff)Oldbitcollector (Jeff) Posts: 8,091
    edited 2009-06-07 17:07
    Those look pretty slick! Cheap wireless is just what the doctor ordered.

    I don't see a US distributor... Let us know if these are worth the effort.

    OBC

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    New to the Propeller?

    Visit the: The Propeller Pages @ Warranty Void.
  • jazzedjazzed Posts: 11,803
    edited 2009-06-07 17:58
    Sounds like what I need for a remote project.
    They're on made-in-china.com ... anybody have an account there?
    RFM12 made-in-china.com link

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    --Steve


    Propalyzer: Propeller PC Logic Analyzer
    http://forums.parallax.com/showthread.php?p=788230
  • Chad GeorgeChad George Posts: 138
    edited 2009-06-07 18:12
    exactly how cheap are these? $1-2 or $10+

    I'm always on the lookout for dirt cheap wireless.
    so far I've found:
    $10 - Nordic nRF24L01+ (part costs on own board)
    $20 - XBee or Nordic plugin modules
    $30 - XBee Pro
    $50 - Bluetooth from various places

    Does anybody think its possible to do Prop-to-Prop wireless without an external trasceiver chip (or maybe a really simple/cheap one)
    I'm thinking of just 10-15ft range...maybe around 20-50k data rates.

    whenever I need anything more than this ... then its easy to justify the nordic or xbee prices.

    but just think of the possibilities for wireless comms between props for less than the price of a connector [noparse]:)[/noparse]
  • InfinityInfinity Posts: 10
    edited 2009-06-07 18:18
    Yeah I have expirences with the rfm12 chip

    But for the propeller you should use the B variante which runs with 3,3V
    http://www.hoperf.com/pdf/rfm12b.pdf
    http://www.hoperf.com/pdf/rf12b.pdf

    The second pdf is the datasheet of the rf12b chip this is the chip which is on the rfm12b and you can find all commands the rfm12b understands in it.

    I used them with avr µC but I don't have a propeller yet so I can't tell you how good the spi modules for the propeller are..

    best regards,
    Infinity
  • Robot FreakRobot Freak Posts: 168
    edited 2009-06-07 18:52
    Infinity, can you post the avr code please?

    Here on college I must use an ATmega32, so I can at least try to port it.

    Kind regards,
    Robot Freak
  • InfinityInfinity Posts: 10
    edited 2009-06-07 19:14
    Hello,

    My code will not work with your atmega32 because it needs 3 PCINTs....

    But there is some code which use polling and will work on your atmega32,
    http://www.mikrocontroller.net/attachment/22506/rfm12.zip (Author Benedikt K.)

    for this code you need a 10k pullup at the FSK/DATA/nFFS Pin. This enables the FiFo of the rf12 chip permanently...

    Oh and this code ist just simple transmitting....there is no protocoll and it use software spi...


    best regards,
    Infinity
  • Robot FreakRobot Freak Posts: 168
    edited 2009-06-07 19:57
    Ok, I understand.

    Thanks anyway, I'll try the code of Benedikt K.

    Kind regards,
    Robot Freak
  • CounterRotatingPropsCounterRotatingProps Posts: 1,132
    edited 2009-06-07 20:18
    Does anybody think its possible to do Prop-to-Prop wireless without an external trasceiver chip (or maybe a really simple/cheap one)
    I'm thinking of just 10-15ft range...maybe around 20-50k data rates.
    Chad,

    do you mean using the PLL/clock to generate the RF and modulate that?

    Think this has been tried by our resident HAM folks ... I don't think·the freq.·would be stable enough to track - it'd have to be wideband and data rate slow. RF noisy and S/N ratio bad?

    - Howard

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    No matter how much you push the envelope, it'll still be stationery.
  • hinvhinv Posts: 1,255
    edited 2009-06-07 21:25
    Are those PCINTs interupts? I am so glad I don't have to deal with interrupts.
    Infinity, I think you will be also.
  • InfinityInfinity Posts: 10
    edited 2009-06-08 12:43
    Yeah interrupts, most atmels only have 2 external intrrupt sources INT0 and INT1, and at amtels with PCINTs most Pins are Interruptsource. (All that are PCINTXX Pins...)

    And no Interrupts are great they help you save alot of CPU runtime.....

    best regards,
    Infinity
  • MicrocontrolledMicrocontrolled Posts: 2,461
    edited 2009-06-08 22:01
    Why are you using an ATmega??? I would rather use the prop.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Toys are microcontroled.
    Robots are microcontroled.
    I am microcontroled.
  • Matthew BurmeisterMatthew Burmeister Posts: 49
    edited 2009-06-08 22:17
    microcontrolled said...
    Why are you using an ATmega??? I would rather use the prop.

    Same here.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Disclaimer: I cannot guarantee any information i post is accurate, but most of the time, it is correct.
    Misses 8 bit computing
Sign In or Register to comment.