Bitcraze Forums

We successfully updated our robot Java code so we are now getting good readings at full SPI speed from the Flow Breakout board. Arnaud and Tobias were very helpful, so thank you and the rest of your team that helped with this. For anyone with a FIRST robotics team who may read this, we will be posti...

I've been using the Flow Breakout board for an FRC (FIRST Robotics Competition) robot design. We are only using the PMW3901 motion sensor in a fixed height above the ground; we aren't using the distance sensor. We had some early issues with readings, and during troubleshooting I noticed that the ini...

OK, I think I have it. Following your suggestions, I modified the Arduino library Bitcraze_PMW3901 to do things a little differently. First, I added two additional parameters to the readMotionCount function, so now it looks like this: readMotionCount(int16_t *deltaX, int16_t *deltaY, uint8_t *squal,...

Thank you. I'll follow those instructions and let you know. Question: how does the chip decide to update the data registers after the read sequence is complete? Is there just a time delay, or some other logic? Thanks.

OK, we had a long delay after the FRC competition season while the kids recovered, and the teacher/coach recovered from pneumonia. I finally got access to our sensor, and I've been experimenting with it at home with an Arduino. I've tried a number of different options for reading the device, but in ...

In the crazyflie code there are about thre or four changes in the data values used in a certain register, and there are a few additional register settings at the end of the sequence. I don't have the listing in front of me to compare or I'd list the line numbers. With the lack of vendor information,...

Thank you, arnaud. I will take a close look at those timing requirements when I get a scope set up. I don't have a lot of control on the SPI interface on the RoboRio, so I may have to bit-bang some gpio pins to get what we need. In the meantime, I noticed that the initialization steps for the PWM390...

I couldn't get the readings I need because the kids have the robot torn down for improvements. In the meantime, I've been analyzing some early data I have, and it seems clear that I'm having a bit readout problem. I was able to show, using a histogram, that I'm losing the 2^4 bit about one time in f...

Thank you for your quick reply, arnaud. One of the difficulties of our control system is that it's cycle time of 20 msec varies quite a bit, by as much as +/- 5 msec. So during one test I divided the delta X counts by the actual time step to see if that would explain the inconsistencies. It didn't. ...

I am a Mentor for a high school team building robots for FIRST Robotics competitions. https://www.firstinspires.org/robotics/frc We are trying to use a Flow Breakout sensor to measure the movement of the robot on the field, and to control the autonomous activities of the robot. We have the Breakout ...