Plotting ECG signal?

RE: Plotting ECG signal?

Ole Morten — Mon, 12 Aug 2013 12:06:07 GMT

Good thing! If you found a specific solution, I'd be happy if you could post it as a separate answer and mark it as accepted, so that others can easily find a good solution to similar problems.

RE: Plotting ECG signal?

Guest — Thu, 08 Aug 2013 09:32:02 GMT

Hello, I solved the problem, timers were not well adjusted.

Thank you for your time

RE: Plotting ECG signal?

Bastiaan — Thu, 08 Aug 2013 09:32:02 GMT

Hello, I solved the problem, timers were not well adjusted.

Thank you for your time

RE: Plotting ECG signal?

Ole Morten — Tue, 06 Aug 2013 11:45:56 GMT

I'm not quite sure if I understand you correctly, but what kind of distortion are you seeing? If you'd like help understanding the issue, it would have been useful if you could upload a zip of your code, so that I can take a look. Screenshots of the app, showing the distortion would also be helpful.

RE: Plotting ECG signal?

Nikola — Tue, 06 Aug 2013 06:34:21 GMT

Yes of course,

I tried ble_app_hrs of this application and it works great, but I got the idea to try to draw the ECG signal on the graph in the application. The idea is to use the sourse code ble_app_hrs with some modifications such as:

//Configure ADC

NRF_ADC->INTENSET = ADC_INTENSET_END_Msk; NRF_ADC->CONFIG = (ADC_CONFIG_RES_8bit << ADC_CONFIG_RES_Pos) | (ADC_CONFIG_INPSEL_AnalogInputOneThirdPrescaling << ADC_CONFIG_INPSEL_Pos) | (ADC_CONFIG_REFSEL_VBG << ADC_CONFIG_REFSEL_Pos) | (ADC_CONFIG_PSEL_AnalogInput2 << ADC_CONFIG_PSEL_Pos) | (ADC_CONFIG_EXTREFSEL_None << ADC_CONFIG_EXTREFSEL_Pos);

I also made some modifications regarding sampling:

APP_TIMER_TICKS(10, APP_TIMER_PRESCALER) , I put the time sampling every 10ms, in the original version it is 1000ms. I checked using PCA1000 and Master Control Panel and indeed PCA10001 sends 100 samples in 1 second. Via potentiometer I have simulated changes in voltage at the ADC input and through Master Control Panel I saw that the value of sent samples different depending on the changing position of the potentiometer (voltage to AnalogInput2 ).

In an application I made that instead of values heart rate prints the value of the samples by the application receives,because I saw a graph drawn on the basis of values heart rate. In the application I have a drawing of ECG signal but with a distortion and now I do not know if the problem is in the application or sourse code wich I used (ble_app_hrs).

I don't know, If anyone has experience with this stuff, advice is welcome.

Thank you....

RE: Plotting ECG signal?

Ole Morten — Tue, 06 Aug 2013 04:55:58 GMT

There isn't any built-in functionality in the iOS app to plot ECG, so this is something you'd have to add yourself. The source code for the app is available here, and it uses core-plot for plotting for example the regular heart rate, so I guess this should be usable for ECG as well.