VM110 Counter

Hello…

I’m working on a hobby project to build a tachometer, My encoder outputs 512 pulses per revolution, it will quickly saturate the 2000Hz limit, when it reaches a speed of 4 revolutions per second. I think I can use a Johnson Decade Counter (4017) to divide the counts as the speed increases? Divide by 2, then by 4, then by 8. etc… I think this should give a very accurate and smooth acceleration curve? Can I use the digital outputs from the VM110 as switches… using AND or some logic chips to control the divider count? Sorry… I’m still learning electronics… and don’t have anyone to answer these simple questions. If someone can post a schematic… that would be very helpful!

Also… If I have 4 analog sensors… but only need to read 2 at a time… is there a way to switch between them using the digital outputs? I’m sure a mechanical relay would work… is there a better solution?

Thanks, for making a great product with exceptional support!
Robbie

Better choice than the 4017 is to use e.g. 7-stage binary counter 4024.
standardics.nxp.com/products … ct4024.pdf

You can select the proper output using a multiplexer 74HC251
standardics.nxp.com/products … hct251.pdf

Connect the three digital outputs of the VM110 to the S0…S1 pins of the 74HC251 to select the input. You have to add pull-up resistors (e.g. 4k7) from he VM110 outputs to +5V of the board.


The output code of the 4017 is decoded to the 10 outputs (not useful in this case). See fig 6 on page 7 of this datasheet: standardics.nxp.com/products … f4017b.pdf