Hi Rod,

Thanks for the heads up on your new tachs. I was looking to build an optical tach but it looks like you've saved me a lot of work.

I do have a couple of questions. I'm pretty new to RC planes so if I ask something dumb, please don't hesitate to let me know!

First, how is the magnet mounted to the back of the spinner? I'm assuming it's not strong enough to hold itself in place.

Second, it would seem to me that the magnet would through off the balance of the propeller/crank/etc and might effect the low speed idle. Any problems? Are two magnets mounted to maintain "prop shaft" balance?

Third, ... and you had to know this would be coming, although maybe not before full production started ... how do I read the tach with my onboard microprocessor/data logger? Does the LCD display have a standard serial interface such as TTL, RS232, RS485, or SPI that I could monitor (receive only) or is it a parallel interface that wouldn't be so easy?

Thanks for any additional information you could provide!

Cheers!

Cub