GP2Y0A21YK update time


I’ve created an arduino project to measure the time taken for a slot car to travel between two sensors. However, the sensors I have tried so far all take too long to respond to make the measurements sufficiently accurate. I tried a ToF sensor VL53L0X, amongst others, and have most recently tried the GP2Y0A21YK.

I need the sensor to trigger the Arduino within a few milliseconds (<5) but, from what I understand of the GP2Y0A21YK, it takes 30mS or so to refresh. ie the car may have passed the sensor up to 30mS previously.

Is my understanding correct; is there a faster sensor of the same type; or is there a better/faster sensor to use?

The sensor will be between 5cm and 40cm from the car when it passes and, ideally, would be directional. The sensor doesn’t need to be able to tell the distance of the car, only that the car has passed. I also want to use only one sensor for each ‘trigger’. ie I don’t want to have a transmitter and a receiver separately.



Hello, Connal.

Unfortunately, neither of the sensors you mentioned are appropriate for an application where you need the sensor to trigger within 5 ms.

The Sharp GP2Y0D810Z0F Digital Distance Sensor, might be a better choice; it has a typical steady state update period of 2.56 ms. However, please note that the GP2Y0D810Z0F is a digital sensor with a fixed detection range; it does not provide a measurement, just an indication of whether there is or is not an object in range.

- Patrick


Thanks for the information. It’s a pity that these sensors and the slightly longer range ones are no longer being made, as they probably would have been OK.

I don’t really want to start making this, if I’m going to have to change the solution.

Thanks for the feedback, though. I’ll have to think again.