Jee Labs Talk

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1. decarus
   

   Hi.JeeNode has caught my attention cause it uses the RFM12B. I've seen the "Building the JeeNode v3" but that required a etched PCB.
   my question is:

   1) How to make the RFM12B connect to a computer via usb (does it need to have a uC)
   2) How to make the RFM12B connect to a servo controller(http://www.cytron.com.my/datasheet/ServoController/SC16AUser%27sManual.pdf).

   my purpose is to make a wireless connection between the computer and the servo controller using two RFM12B. If possible a camera too =D.

   any help would be greatly appreciated.. thank you

   Posted 06/09/2009 07:41:15

2. jcw
   

   1) I use a JeeNode (obviously) - with a little USB-BUB board which converts USB to FTDI. The benefit is that you only need one USB connection, and can plug different JeeNodes in as needed.

   2) You could use the Arduino's "Servo" library, which would work with up to 8 servo's on the JeeNode I/O pins. For more servo's I'd use the (upcoming) "Expander Plug", but for really precise control a dedicated I2C or serial controller such as the one you mention is no doubt better.

   For the cameras, you have to be careful with the amounts of data you want to buffer and send. I've been able to get a C328 going, but only at very low resolutions because of the amount of data involved. This is one of the reasons why I'm adding extra memory via I2C EEPROM chips.

   Good luck with your project :)

   Posted 06/09/2009 11:25:58

3. decarus
   

   1) Hmm~~ I'm starting to get how it works. But is it possible to replace ur RFM12B with a RFM22(higher data rate,30Mhz crystal oscillator)?

   2) (http://www.hoperf.com/pdf/RFM22transmitDEMO.pdf) is this the way i should connect the RFM22/12B to the servo controller? The servo controller have 2 connection UART/FTDI & USB.

   Let say(example) I have two transceiver. One is connected to the computer
   (RFM22/12B ->JEE-NODE -> USB-BUBUART and another is connected to the servo controller
   (RFM22/12B ->JEE-NODE (necessary?) -> Servo controllerUART interface
   is JEE-NODE necessary or can the RFM22/12B connect directly to the uC of the servo controller.

   3)wait~ can one of the transceiver receive and send data at once?(Send command to servo controller while receiving video data from camera)

   4)How much is the cost of shipping to malaysia? (possible?)

   5)Can one JEE-NODE control two RFM22/12B?

   6)IS there any other board that can convert RFM22/12B to UART other than JEE-NODE

   7)The RFM22/12B pins are too complicated. What kind of pin(interface) is that?

   sry if i'm asking too much. :P

   Posted 07/09/2009 06:14:38

4. jcw
   

   1) the RFM22 logic is different, and requires a different driver - see also the comments here:
   

          http://news.jeelabs.org/2009/08/26/room-plug-design/#comments
   
   2) you cannot connect the RFM module directly to a servo controller, neither one would know what to do, you need a microprocessor and software in between
   3) not on the same radio frequency
   4) see http://shop.jeelabs.com/pages/shipping
   5) technically, it could, but the RF12 driver software would need to be adjusted, and it may be too much work for one JeeNode to handle two RFM12B's at the same time and do something useful with the data streams
   6) only one I know of, is about the same as a JeeNode: http://code.google.com/p/strobit/
   7) SPI, see http://en.wikipedia.org/wiki/SerialPeripheralInterfaceBus
   No, you're not asking too much, but I suspect that you're [i]expecting[/i] too much :)
   Sending servo information and especially streaming video back at the same time will require more cpu power, buffer storage, and RF bandwidth than a basic JeeNode can handle. It may work on a single JeeNode if you send only a very small image every few seconds but even that will take some careful design and use of available resources.

   Posted 07/09/2009 07:50:13