RF communication - multiple sender - 1 receiver

[Macgyver]

yung RFM12b na module, aside from futurelec, meron din pala sa sparkfun.  And may library na for arduino.    mukhang good option ata ito ah.

[bravokilo]

Hi Mcgyver, what's  the news on the futurlec TX and RX.I opened he link and 1) they are all on the same frquency, so many the RX will hear any of the TX. I noticed, that we need to use an encoder and decoder. HT12D was mentioned.

I would think that ID will have to be in the encoder and the decoder traffics the data to the corresponding storage.Let us say we have 3 TXs. Every TX has an ID which opens up a receptor port.The data is sent to that port.

It's like we have 3 data storage in the MCU. Each storage is activated when a corresponding ID is received togetehr with the data. Then later, when we want to see the information, the MCU scans all these data ports.

Just to illustrate:

     Suppose you have 3 guards in a buidling and we gave them radios to report to an unmanned station. We can set it up in two ways:

1. One RX and one tape recorder(like a telephone voice recorder).The guard IDs himself, then
    leave a message. Messages are  reviewed by rewinding and playing the recorder.

2. One RX but 3 tape recorders. Guard sends an ID(in the old days touch tone) which turns on 
    a particular recorder. Then he sends report.

     Collision cannot be avoided if more than one guard is reporting. What can be done is to have have a "send back" transmitter and RXs with each guard a busy light. These will have to be on a different band.

BK

[Macgyver]

I'm still haven't bought the transceiver modules yet. Hopefully this April I'll be ordering them.  I'll try to compare prices and shipping costs among different suppliers.

I haven't downloaded the library I found but it seems like it will solve my problem. 

There's an adruino library for the rfm12b.  Based on the description of the library, the transmitter will "probe" the airwaves first to see if there's an existing packet being sent. If none, then it will try and send one.

I think there's also some collision detection routines built into the library (probably ack packets) so hopefully, the library will handle all that nitty gritty things and make sure that what I send will be received by the receiver no matter what. I'll just have to use it.

That means either I'll have to shift to arduino or port the library to be able to use it with PIC.   Or hopefully I'll find a pic library for that.

[insomartin]

I'm still haven't bought the transceiver modules yet. Hopefully this April I'll be ordering them.  I'll try to compare prices and shipping costs among different suppliers.

I haven't downloaded the library I found but it seems like it will solve my problem. 

There's an adruino library for the rfm12b.  Based on the description of the library, the transmitter will "probe" the airwaves first to see if there's an existing packet being sent. If none, then it will try and send one.

I think there's also some collision detection routines built into the library (probably ack packets) so hopefully, the library will handle all that nitty gritty things and make sure that what I send will be received by the receiver no matter what. I'll just have to use it.

That means either I'll have to shift to arduino or port the library to be able to use it with PIC.   Or hopefully I'll find a pic library for that.

woot woot! tutorial! tutorial!

[Macgyver]

langyang futurlec,  di pa din dumadating  inorder ko para dito.  1st week of April ko pa inorder wala pa din.  Baka nawala na sa Philpost ah.

[RiDdLeR???]

thats way too long, check mo sa website nila yung status ng order mo.  i've purchased twice from futurlec before and I received both within two weeks time.

[Macgyver]

may binigay sila, parang tracking sa HK post.  I think na send nila pero malamang sa Philpost natin.  Hay kainis!  Nag email na rin ako sa futurlec.  Sana naman di masayang pera ko.

[e-tronix]

hindi namn cguro antay antay lang, kung magka ganun man hindi din masasayang yun kc pkinabangan yun ng iba. ahehe

i have not ordered from this supplier's yet but i think im now hesitant, even for 1 week  of not recieving my orders from china grabe na kaba ko. i have ordered from chinese supplier though several times since last yr.

[rdpzycho]

HK galing? ang typical delivery times ko kapag HK is 3 to 4 weeks on Registered Mail.

nakalimutan ko na 'yung forum na merong nagche-check kung dumaan sa kanila 'yung package based sa number. kung hindi kasi, doon na ia-advise na i-claim 'yung insurance.

[Macgyver]

mukhang galing thailand eh.

"Your order has been shipped out from our Asia distribution center Thailand via HongKong Post with the registered shipping number RB 050 600  665HK" 

pero HK post daw. 

Tapos sa HK post tracking website


"Destination - Philippines
The item (RB050600665HK) left Hong Kong for its destination on 12-Apr-2011."


Tagal naman nito.    So far ito pa lang yung order ko abroad na missing in action.  Pero 1st time ko mag order sa futurlec.
 

[Macgyver]

Eto na.  Dumating na mga RF modules ko.  Sa sobrang bagal nung unang order ko, umorder na ko sa iba so may 5 akong sobra.  Yung isa binili na ni Glutnix.


Since the RF module runs on 3.3v as per datasheet I've implemented some levelshifting.  Kinaya naman ng voltage divider so I used 2 resistors  4.7k and 10k. All output pins going to the RF module from arduino goes to their own voltage dividers.   The output of the RF module goes directly to the pin of arduino.  Arduino will still see 3.3v as logic 1 so no need to have a 3.3v to 5v level shifter.


The module uses SPI so medyo madali na, and may arduino library.


The test setup is 3 arduinos. 

One Arduino is set as NodeID#13  (I can specify any node number).  This is used in the data packets.   I've set this to send a packet every 500ms. 

A second Arduino is set ast NodeId#17.  This one will send a packet every 100ms.


A 3rd Arduino is the main receiver,  it will also send a packet (para manggulo ng airwaves).





Eto yung video ng capture of packets.  Note that there's a sequential packet ID so I'll know if there's a missing packet or not.


http://screencast.com/t/5rM39PBqtKq



Details of the RF module and datasheet is in here

http://www.electronicslab.ph/forum/index.php?topic=26957.0

[bravokilo]

By the way, you can have many RC ransmitters, say 9 but each one is to send a particular channel only. TX 1 sends Ch1, TX2, 2, etc...

SA RX, isa lang, for example may 9 output ports ka na may servo. hinde mag cocolission yan.


BK