# Building an tach for a LMS mini mill



## BMyers (Mar 31, 2011)

I have been tricking out my LMS mini mill. I knew the new servo drives had a port for a tachometer but the budget couldn't justify the cost. I did some research and found a guy at cnczone that had hacked the serial string and provided Arduino code to decode the string and drive an LCD. 
I decided to copy his effort.

Prototype:






It works:






Circuit board for micro controller and cable to LCD display:






Enclosure with display:






I tested with an arduino UNO but as soon as a nano arrives that will be controller that mounts on the pc board


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## Twmaster (Mar 31, 2011)

Nice looking so far. You could also just use a Mega168/328 with a resistor and a cap saving the size and expense of a Nano.

Got a link to that stuff on CNC zone?


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## BMyers (Mar 31, 2011)

I picked up a nano for $9.00 and being lazy, it seemed easy to me.
go here:
http://www.macpod.net/misc/sx2_tachometer/sx2_tachometer.php

the web owner has been talking about making a kit available.


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## Twmaster (Apr 3, 2011)

Thanks. That's interesting. You got that Nano cheap enough not to bother with a bare chip...


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## ibuildstuff4u (Apr 3, 2011)

Looks great! I wish I had the SX2 mill so I could do the same mod.

I see you added I gauge digital readouts to the mill and wanted to know if you could post some pictures showing how you mounted them to the table. I'm about to install some on my mill and the more ideas I have the better!

Thanks, Dale P.


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## BMyers (Apr 4, 2011)

go here:

http://www.homemodelenginemachinist.com/index.php?topic=13795.msg142028#msg142028

X mounts just like the Y except the tab on the reader goes down instead of up


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## BMyers (Apr 16, 2011)

Macpod.net now has a nice kit available. Nice design.
http://macpod.net/misc/sx2_tachometer/sx2_tachometer_kit.php


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## macpod (Apr 16, 2011)

Hey all,

I'm the cnczone guy that figured out the protocol. Now there's some lower cost options other than LMS's 125$ unit. That price was way too high. 

If you wanted to totally roll your own, I provided some Arduino code and a description of the protocol on the above links on macpod.net

I made a kit too as BMyers pointed out which you can choose to solder yourself, or just have me solder. The kit includes everything you need except an enclosure for the tachometer device. For the display I use red 7-segments as I find them to be very easy to see. I also have green segments and if you really wanted I can get blue 7-segments but those cost a bit more.

By the way, this kit should work with both the SX2 Mill (HiTorque LMS mill) AND the CN2 (HiTorque LMS Lathe). Even though 4 digits should ever be used by these mills, I added a spot for a 5th digit and a programmer header in case one of you has some other crazy setup that could use something like this 

Here's some pictures of the kit. The orange thing you see there is a potentiometer used to adjust the brightness of the leds. In-person these are much easier to read, camera sensors really don't do that great a job photographing leds...


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