TouchDRO Machine Position Digital Readout for Emco Maximat V10P Lathe

This is a outstanding machine DRO for hobbyists, not just an outstanding DIY project, but a super DRO even compared to high-end pro machines. The beauty of TouchDRO is that it uses a (cheap) Android tablet for the display and control (I used a 1st-generation Nexus tablet – $50 on eBay) while the scales connect to a small (user-built) box that wirelessly sends data to the tablet via Bluetooth. The extra cute thing about this particular DRO installation is that all that parts are very small don’t interfere with any travel distances or setups on this already smallish machine.

2014-09-25 22.18.32

Below are a schematic and a link to the TouchDRO website.

TouchDRO MSP430

TouchDRO Link: http://www.yuriystoys.com/p/android-dro.html

This particular circuit is designed for quadrature-output scales only. It will not work with the cheaper Chinese “caliper” or other similar scales. Examples of quadrature output scales are optical scales and some magnetic scales. In my particular case, I used magnetic read heads made by Renishaw (Model LM10) and linear magnetic tape that I purchased used on eBay. This choice was made to get the smallest linear measurement parts possible.

Below are links to Eagle files for the above circuit. Note that you can get an MSP430 Launchpad board for less than building the above board, but I wanted tiny size and compatibility with the header connectors on my read heads, so I designed my own board and got PCBs made at OSH Park.

Eagle schematic: https://dl.dropboxusercontent.com/u/2186623/MSP430_TOuchDRO_surf.sch

Eagle PCB layout: https://dl.dropboxusercontent.com/u/2186623/MSP430_TOuchDRO_surf.brd

Or, if you want to just use my layout, you can order blank PC boards from OSH Park here: https://oshpark.com/shared_projects/QH96j7xH

Read heads are Renishaw LM10s off eBay for about $100 each. These can be expensive, but I wanted the tiny size. I also got the linear magnetic scale tape off eBay. Total cost was about the same as a good Chinese DRO package like Sino.

IMG_4530
Z axis scale mounted. The lead screw, drive shaft, and the front of the saddle have been removed. The bar is 0.25″ x 1″ x 28″ aluminum stock with a channel cut for the magnetic tape.
IMG_4522
Z-scale mounted with lead screw and drive shaft reinstalled.  The read head pokes between the lead screw and drive shaft to reach the magnetic tape. The 0.25″ dimension of the aluminum bar has to be thinned to 0.21″ to not interfere with the saddle.
IMG_4438
Cross slide (X axis) magnetic tape holder milled from 1″ x 0.25″ aluminum stock. Mag tape not installed yet. The bite out of the bottom allows clearance for the cross slide lock cap screw.
IMG_4443
Tapping the cross slide to mount to X scale
IMG_4520
X-scale mounted. Small overhang has to be to the front of the cross slide (rather than the back) to not interfere with the V10P’s milling column (not seen, but just off the right edge of the picture).

 

 

IMG_4529
Both X and Z read heads mount in fixed positions on saddle. No scale wires are dragged by the saddle or cross slide since TouchDRO sends position to the tablet wirelessly via Bluetooth. White wire at the bottom brings power to MSP430 & Bluetooth transmitter in the black plastic box.
IMG_4518
MPS430 Touch DRO circuitry and Bluetooth module on OSH Park board fits in small plastic box that mounts under the saddle. HC06 Bluetooth transmitter is also from eBay and plugs right into a header on the board.
IMG_4561
Tablet holder before paint
2014-09-25 22.18.32
Tablet and tablet holder on the machine. TouchDRO’s Tablet display beats the cr@p out of clunky DRO boxes, both for readout clarity and data input convenience.
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8 thoughts on “TouchDRO Machine Position Digital Readout for Emco Maximat V10P Lathe

  1. I am interested in your conversion of the v10-p push button controls to the modified version shown on your machine. Are instructions for the modification available?

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  2. Hi Lens,

    Hi have a maximat V10 P will try to do you DRO mod. Looking good, and clean, instead of tied in chinese calipers everywhere.

    Would you care to share the files ( if you have ) for the aluminum parts ?
    Saves me the puzzle.

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    • I’m afraid I just did a “fit and cut” sort of installation and made no drawings. What I can tell you is that all the mag tape support bars were made from 1″ x 0.25″ aluminum stock. I milled channels (I think about 0.12″ deep) to accept the magnetic tape. The channel width for my tape was 0.4″. I tapped holes on both the cross-slide and the bed to mount the bars. There is also a semi-circle notch in the cross-slide bar to accommodate the the lock cap screw.

      One important thing you can’t see from the photos is that the bar that mounts on the bed had to be thinned a bit (down to 0.21″ I think, but you should test fit yours) so that the inside edge of the saddle did not hit it. The part that hits if you don’t shave the bar down is the back of the handwheel axle. It protrudes *just* enough to hit. It’s a bit tricky to see, but if you try to slide a 1/4″ bar between the saddle and the bed, you will see where the contact is.

      What I did for installation is mark the height I wanted (between the drive bar and the leadscrew) with a Sharpie. Then I removed the leadscrew and drive bar to do the install.

      I hope this helps.

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  3. Thank you very much for sharing the project.

    I only have one doubt because everything works perfectly and it is as far as the probe

    It gives me the feeling that the app still does not contemplate this option, is correct or I am wrong.

    Apparently: the firm Quandrature Firmware for MSP430 LaunchPad 1.2 implements the touch probe but not the app.

    I understand that the touch probe function is that when the sensor closes the circuit the app should automatically set a new source. I also understand that it will be necessary for the app to set the diameter of the touch probe sensor.

    Thanks for the clarification.

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  4. I have been reading up on the renishaw read head and magnetic tape. Seems like a lot of versions relative to resolution , output style etc for both the readhead and tape. I can see the readhead model in the pics but what made you choose these in particular and what style magnetic tape tape did you use ?

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    • Hi Mike – My choices were mostly based on eBay cost, figuring that even a low-end Renishaw setup would perform at least as well as a Chinese system. I was able to get LM10 heads for $75 at the time and the tape was $80 per meter. One meter is enough for both the bed and cross-slide on a V10P (I didn’t do the mill Z). The tape is still available at the price I paid: eBay Magnetic Tape

      When I bought, I wasn’t 100% sure what resolution I’d get with “1mm or 2mm pole” tape. I wasn’t 100% sure what that meant but guessed that 1mm poles would probably give twice the resolution of 2mm, but either would probably be fine. I think I bought “2mm pole” tape and I’m still getting 0.0001 resolution. The LM10s don’t seem to be $75 any more but the heads don’t have to be those. If you search eBay for “Heidenhain LIDA 47”, there are several for $35. Heidenhain tape is available from the same seller though I doubt it’s required for their heads (though it may be cheaper).

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