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how to send data from end nodes to coordinator using different RF channels using TIMAC

Other Parts Discussed in Thread: TIMAC, MSP430F5438, CC2520, CC3200, MSP430F5438A, Z-STACK

hi,

i am using TIMAC for sending sensor data from different nodes(end devices) to coordinator.the hardware used is cc2520+msp430f5438 experimenter board.

i want to send sensor data from each end node to coordinator in a different RF channel in the 2.4 ghz range i.e

i want to send sensor data from one node to coordinator in channel 11(2405MHZ),next sensor data from another node  in different channel say channel 12,13 and so on.

i want to ask whether the coordinator has a mechanism in TIMAC to accept data simultaneously from different nodes through channels .

is there a mechanism to set this,if yes plz help.

thanks

  • As I know, TIMAC can't accept data simultaneously from different channels .

  • Dear Yikai Sir,

    Thank you for your answer.

    But can you tell me a way to overcome my problem.

    i am using cc2520+ msp430f5438 experimenter board for my hardware.

    i want to send accelerometer sensor data from multiple nodes to coordinator .I am using TIMAC. i am using single channel across all nodes to send the data.due to which burden is more on coordinator which is quite visible.

    when i was able to send sine wave from single node to coordinator,i was able to receive the wave upto 100hz and was able to see the FFT peak  of 100hz at the receiver end.when i used 2 nodes and sent  sine wave from each i was only able to construct a peak for around 40hz and when i used 3 nodes to send sine wave i was only able to construct a peak of around 20-25 hz.

    i want to construct a peak of around 90-100hz at the receiver end from 3 nodes.is there a mechanism which i can use to achieve it.

    i am using ADC(8bit) with a sampling frequency of 2121hz to pass the digital signal generated from analog signal of function generator .

    i am using 2 bytes of packet's data field to send and receive the sine wave.even if i increase the number of data fields in the packet and increase the wait period(time taken for transmission between one packet and another packet)there is no change in performance.

    can some timing mechanism be introduced at the sender side of the node such that the data can be sent from different nodes at different times so that all nodes can send the data of desired frequency and the receiver is capable of capturing the data and there is no loss of data packets.

    can you suggest some thing.

    thank you.

  • TIMAC is based on IEEE 802.15.4 standard and is only suitable for low data rate. Your application seems need more than low data rate and I would suggest you consider other protocol such as wifi. Maybe you can consider CC3200 which is a wifi SOC and might be suitable for you.

  • Yikai Chen Sir,

    As you said TIMAC is based on IEEE 802.15.4 standard and is only suitable for low data rate.we saw from TIMAC document  and TI site that it is around 100kbps.

    So does low data rate means we can not  have a signal frequency of approx 100Hz or more with a sampling frequency of around 2121Hz sent and received used TIMAC

    Can you please suggest approximately  how much frequency signal we can pass using TIMAC and approximately with what sampling frequency.

    The hardware we are using is CC2520+MSP430F5438 experimenter board(msp430f5438a controller) with ADC (8 bit) configuration and sampling frequency approximately 2121Hz.

    Thank you

  • I don't have experiences on such data transmitting using TIMAC. However, I have experiences on data transmitting using Z-Stack which is also based on 802.15.4. I would say 16K bits per seconds is the limitation for application.

  • So using Z Stack the max is 16K bits per sec or 2000 Bytes per sec.

    Then can you plz tell how much frequency can be constructed  safely using 2000 Bytes per sec.

  • I don't understand your question "how much frequency can be constructed  safely using 2000 Bytes per sec? "

  • Sir,

    I mean to ask up to how much frequency signal i can pass for 2000 Bytes per sec i.e upto how much maximum frequency for a signal can i take so that it can be transmitted and received and reconstructed  at the receiver

  • You can try to send 80 bytes every 50 milliseconds.

  • So Sir,

    you mean to say I can reconstruct my signal of 100Hz frequency  at receiver with the above settings and also how much i can expect to go

    Thank you

  • From my experience, the sender can send data in 80Bytes@25Hz and receiver can receive the data in the same rate. If you want to reconstruct your signal at 100Hz, I think the sender can only sends 20 byte every 10 milliseconds.

  • Hi Yikai Sir,

    I want to know how much maximum frequency can be transmitted and reconstructed at receiver side using Z stack.

  • sir,

    you said 16Kbits per sec is the limitation of application.

    Can you please tell me the maths behind arriving at this value

  • Yikai Chen Sir,

    What is the mathematical calculation behind getting 16K bits per sec as a limitation for application

      

  • There is no math calculation. These data is based on my application and 16k bps is the max bandwidth that I can reach.

  • ok sir,

    then can your make a calculative guess what can be the maximum frequency  we can expect to pass with 16kbps and also what can be the bandwidth for TIMAC (effective data rate given in documentation is 100kbps) and frequency that can be passed using TIMAC