If all else fails you can MacGyver one together from an old ball mouse, some pennies and a peanut butter jar lid.
EDIT:
There's no simple way to electrically change the PPM of an opto circuit like this, that's why Taito and others resorted to different gearing and different reluctor wheels when they needed a different output speed.
But, I just got my board and and had a look at the design Looking at the chips being used, the LS123 (IC3), which is really the business end of this device, has an option for a trimmer as can be seen on page 6 here:
http://www.ti.com/lit/an/sdla006a/sdla006a.pdf
that'd likely be the best way to add in any adjustability. alternatively you could swap out for different resistor values that are more amicable to whatever PPM spinner you're using.
EDIT:
There's no simple way to electrically change the PPM of an opto circuit like this, that's why Taito and others resorted to different gearing and different reluctor wheels when they needed a different output speed.
But, I just got my board and and had a look at the design Looking at the chips being used, the LS123 (IC3), which is really the business end of this device, has an option for a trimmer as can be seen on page 6 here:
http://www.ti.com/lit/an/sdla006a/sdla006a.pdf
that'd likely be the best way to add in any adjustability. alternatively you could swap out for different resistor values that are more amicable to whatever PPM spinner you're using.
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