I want to trigger a laser externally and I want to trigger it when a rotating small wind turbine blade passes a specific angle. I have a digital signal which tells me when the blade passes that angle. The blade rotates at 13 Hz, but I want to trigger the laser at 1 Hz.

So I need a tick counter that can count the picks in the digital signal and ignore 12 of them, but passes the 13th one. I am looking for a stand alone sensor that can do it for me. That would be great if I can adjust those frequencies too. Any suggestions would be appreciated.

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    \$\begingroup\$ "wanna" is not english! \$\endgroup\$ – Leon Heller Feb 21 '18 at 17:52
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    \$\begingroup\$ I was already working on it. Fixed! \$\endgroup\$ – Transistor Feb 21 '18 at 17:53
  • \$\begingroup\$ Suggestion: how about designing one rather than asking us a shopping question (that will likely get closed). If you want to buy one then this isn't the place for you I reckon. \$\endgroup\$ – Andy aka Feb 21 '18 at 17:57

I am looking for a stand alone sensor that can do it for me.

I have never seen any sensor with a divide by 13 feature built-in. You will need to build a circuit to do it.

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Figure 1. A divide by n circuit based on the CMOS 4017 Johnson ring counter. Source: Electrosome.

The 4017 can be cascaded to count to more than ten as required. Use Q0 as your output and connect Qn to the reset (MR) to get the counters to reset when Q13 turns on.


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