Hello, I’ve looked at a few site and datasheets for the PMW3901 and found that the speed is listed as 7.4 rad/s. Why is rotational speed specified? I want to know the max X/Y speed for the PMW3901. Other optical flow sensors list the max IPS (inches per second). For example, the ADNS-3080 has max 4…

Hi @finallyfunctional , because the sensor measures a flow rate, which is in rad/s. The maximum horizontal speed depends on the distance to the moving surface (e.g.: ground). So if you are at 1m, the maximum speed is 1x7.4 = 7.4m/s and if you are at 10m altitude, the maximum speed is 10x7.4 = 74m/s…

This is how you can compute the equivalent ground velocity: PX4-Autopilot/optflow_fusion.cpp at fb3adc3faa9154a42a0bef35577bff1e8a95fd72 · PX4/PX4-Autopilot · GitHub and the compensated optical flow is computed like that: PX4-Autopilot/optical_flow_control.cpp at fe80e7aa468a50bec6b035d0e8e4e37e516…

I am trying to gain a better understanding of how to obtain velocity using the PMW3901. I have read through the PX4 source code and want to use a simplistic example to verify whether or not I have the right idea. Suppose my drone is flying straight and level in the PMW3901 X-axis direction at 10 me…

Hi Bresch, I’m using the PMW3901 with Arduino core and facing two issues: I can detect the ToF sensor’s I²C address using a scanner, but I can’t receive any data from it. How can I convert the deltax and deltay motion counts from the PMW3901 into velocity in m/s? Thanks in advance!

[image] Abdo: How can I convert the deltax and deltay motion counts from the PMW3901 into velocity in m/s? You would need the distance data as well, check my previous answer: [image] PMW3901 speed vel = flow_rate * distance and flow_rate = delta_x / …

Having another question PMW3901 - ATK have xshut for TOF (VL53L1X)? [image]

PMW3901 speed

bresch November 23, 2023, 2:11pm 6

vel = flow_rate * distance
and
flow_rate = delta_x / PMW3901_SAMPLE_INTERVAL.

Regarding the 385 scale factor, it’s given by the manufacturer to convert a register value to a “delta_x” flow.

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PMW3901 speed

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