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C5505 ECG Design

slycaldron
Prodigy 40 points

So I've got the goal of writing a heart rate arrythmia detection algorithm using the C5505 DSP EVM board, and want to use the analog front-end to simplify the process. I am currently running into two unrelated problems.

 

I am running the ECG demo, and it reacts to voltage signals, but I'm having some trouble up at the front-end with getting a reliable signal from an ECG generator to be read correctly (the display is showing a mess, not the clean ECG signal it is supposed to be showing.) anyone know what are the best ways of outputting fake analog signals from Labview and getting them cleanly transmitted into the front-end? I expect this is a simple problem, but it is frustrating nonetheless, and an important hurdle to overcome.

 

secondly, I am trying to setup Code Composer Studio and Matlab's Real Time Workshop to let me write the algorithm in Simulink, with the goal of embedding the program on the DSP chip. So far, I have been trying to modify existing Matlab code optimized for C6000 dsps, and getting it to work on the C5505. This has proved problematic, and I am seeing many block modules saying "bad link." It would be greatly appreciated if someone could help me with setting up Real Time Workshop.

 

thanks, I understand this is ambitious, but I believe it is possible, if I can just get help with the setup steps.

  • 0
    TI__Intellectual 2530 points

    Hi Slycaldron,

    It would be helpful if you could provide a little more information about your ECG setup.  Are you using the MDK (Medical Development Kit) ECG front-end from TI with the C5505 EVM?  If you purchased the MDK you should have received the Quick Start Guide document that includes information on what type of ECG cables to use, are you using those ECG cables?  Also what ECG generator are you using? 

    In case it helps here is a link to a document on C5505 ECG MDK:

    http://focus.ti.com/general/docs/litabsmultiplefilelist.tsp?literatureNumber=sprab36a

    Regarding your Matlab question I am checking with our contact at Matlab, will let you know as soon as I hear back.

    Best regards, Vishal

  • 0 in reply to Vishal Markandey
    Prodigy 40 points

    I am using the MDK ECG front-end, and I am using Labview's Biomedical Source kit to generate analog voltage signals from files on the Physiobank MIT-BIH database, and output them through the Labview DAQ card...I have not yet been able to verify, however, if Labview is actually correctly outputting voltage signals (if not, that is obviously where the problem is)...

    I am currently ordering the recommended Biometric ECG cables, but they have not yet arrived. What are the important components contained in those ECG cables? I was unable to find any schematics for them. Are there isolator circuits contained in the adapter that assist in noise reduction that I am not accounting for?...I was hoping to plug the millivolt voltage signals directly from the labview DAQ into the pins with wires.

    Once the labview's output response is confirmed, I expect to plug in the cables and confirm if the ECG system is correctly identifying the signals I am using.

     

    thanks!

     

    Dan Calderon

    Owleye

    Electrical Engineering '11

    3618762106

  • 0 in reply to slycaldron
    TI__Expert 8065 points

    Hi Slycaldron,

    I have the same assumption that the ECG cables may have some isolator curcuits inside. I believe you can use regular wires for each input. We actually made a connector with blue wires once and used the connector with a ECG simulator. It worked for us. Please note that it was only test purpose (no safty definitely).  

    Thanks,

    Peter Chung

     

  • 0 in reply to Peter Chung
    Prodigy 10 points

    Hello,

    I'm in the same group with Slycaldron working with the C5505 EVM Heart Rate detection board and program.  We've managed to receive a clean ECG signal however our heart rate is not displaying.  We don't know the reason why we can't find this signal because the heart rate signal displayed is very clean.  When we look at the status of the leads, most of the time all the leads are bolded (inactive) and once in a while the RA, LA and LL leads light up (active) for one second or so but we know we have the 3 leads in.    Sometimes we can see that the HR flashes 250, which we're assuming is the max, so something is reading the signal but not reading it correctly.  Below is a screenshot of our data, as you can see HR is displayed as zero.  Is there some type of switch we need to turn on for the program to start analyzing the data? PLEASE HELP US!

    Thanks,

    Team OwlEye

  • 0 in reply to owl_i
    TI__Expert 8065 points

    Hi,

    It appears that the lead-off detection is not working. In order to display HR, the RA, LA, LL, and RL should be detected correctly. If those four leads are detected as "off", then HR won't be displayed.

    On the board, U18, U19, and U20 are related to the lead-off detection. Also, please check out I2C interface. The C5505 reads lead-off information through I2C when I2C_INT is asserted. Hope this helps.

    Thanks,

    Peter Chung

     

  • 0 in reply to Peter Chung
    Prodigy 10 points

    Hello...

     

    can you answer me please?

     

    Do you sell ECG cables with ECG MDK or i have to purchase them alone?

  • 0 in reply to Asaad Kaadan
    TI__Genius 13045 points

    Assad,

    The sensors are not provided with the MDK kits.  Recommended sensors are defined in application notes for each particular MDK.  For the ECG the app note can be found here: http://www-s.ti.com/sc/techlit/sprab36.

    Regards.

  • 0 in reply to TommyG
    Prodigy 40 points

    Hi,

     

    we have to buy PPG and ECG sensors from "biometric cable"   . Does this company have any distributor in US? Do you know how we can order these sensors ?

     

    thanks,

    rasoul