Hi Velleman - Team,
I am new in this forum. I have build the ALLBOT VR612 with success. Nice Robot !!!
But unfortunately there is a bug in the chirp Function of your manual.
It must be i++ in the for statements and there must be a + in the delayMicroseconds((355-i) + (speedms*2)); statements.
All other things of this manual work fine.
But there is another problem in the example sketches. If you click on an example, the source code comes unformatted and it is a lot of work, to format it.