CNY70- Sensor for Mobot Line tracking

Our visible light line tracking sensor will be retired and be replaced soon by a better performing sensor based on the CNY70 reflective sensor.

The CNY70 is small, housed in a 7x7x6mm (LWH) package, you could easily fit 5 on a peso coin.

The CNY70 sensor was picked for the job because it has a couple of features we felt makes it ideal for line tracking applications.  First, it houses the infrared emitter and receiver in one package, meaning these are already arranged and fixed to a optimum position, freeing the user from the difficult task of having to physically align the emitter and receiver. Next, it is sensitive to colors, maybe not a good feature for some sensing applications, but definitely a good one for a line tracker. 

I built a circuit to quickly evaluate the CNY70 sensor for line tracking application.

A line tracking sensor using 3 CNY70s is built on a prototyping PCB for quick performance test.

The 3 CNY70 sensors arranged as in the photo will provide good coverage for 3/4″ wide track at 5mm detection height.

As soon as the test board was built and put the work, the  CNY70 based line sensor worked like a charm. Tested with all sensitivity trimmers set to about 90% of the maximum, the line sensor correctly sensed the test track with good precision. It worked well even when the sensor tip is nearly touching the sensor track surface, or held back up to 10mm away from the track surface. Without fail, even when the test board is occasionally illuminated by strong light.

Work on our new generation line tracking sensor using the CNY70 is underway. Although line tracking is the first thing that came to mind when I chanced upon this sensor, it has several other potential uses. Expect some more application ideas from this blog. For those who can’t wait and want to use one right now, the CNY70 sensor is now available at e-Gizmo.

* The schematic shows the circuit for one sensor only. Duplicate the circuit to put as many sensors as you want for your line tracking sensor.