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

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

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

1 Like

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

@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(", ");
1 Like