How to Serial print on Arduino the camera raw data format float RGB888?

#1

We copy from Edge Impulse and paste raw image data into our Arduino programs to test if the static_buffer is working, The raw data is in the form RGB888 which is in 3 byte (float) format.

Example image raw data from Edge Impulse:

0xddddd1, 0xddded1, 0xdbdcce, 0xdbdcce, 0xd8d8cc, 0xdcdcd0, 0xddddd1, 0xdbdbcf, ...

but to serial print that same data on the Arduino for debugging purposes seems a bit confusing. I know that I could eventually write the code using some clunky convert to byte,print “0x” then 3 bytes in HEX format, correcting for non-printing zeros etc, but does anyone have a function or example of how to do it efficiently?

In the static_buffer the features array is already defined, so printing it once data has been copied to it would be a good starting point:

static const float features[] = {

    // copy raw features here (for example from the 'Live classification' page)
    // see https://docs.edgeimpulse.com/docs/running-your-impulse-arduino
};
#2

@Rocksetta just pass in true as the last argument to run_classifier. It will print the features for you.

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#3

Thanks @janjongboom but that has 2 problems:

  1. I want to test that my sensor data is correct before connecting an Impulse library.

  2. The output is similar to what I am getting showing floating point numbers and not 3 byte HEX format shown on EdgeImpulse…

Here is my printout using a Nano33BLESense

Edge Impulse standalone inferencing (Arduino)
Features (4 ms.): 0.866667 0.866667 0.819608 0.866667 0.870588 ........(lots more).....

Predictions (time: 714 ms.):
is-microcontroller:	0.964844
unknown:	0.035156
run_classifier returned: 0
Predictions (DSP: 4 ms., Classification: 714 ms., Anomaly: 0 ms.): 
[0.96484, 0.03516]
    is-microcontroller: 0.96484
    unknown: 0.03516
Resize (fit, squash...), interpolation and other doubts
#4

@Rocksetta try this:

    for (size_t ix = 0; ix < signal.total_length; ix++) {
        float value[1];
        signal.get_data(ix, 1, value);

        ei_printf("0x%06x", (int)value[0]);
        if (ix != signal.total_length - 1) {
          ei_printf(", ");
        }
    }
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