House Mill - Cowells Upgrade

[Twizseven]

Now my house mill is sat alongside its sibling lathe, i've decided it needs an upgrade.  I have DRO's fitted on my ML7 and Colchester and Chester Mill and felt that the Cowells was left out.  So this morning a box of goody's arrived ( 3 magnetic encoders, 1 meter of support profile and magnetic tape.  I had already made a control box using the circuits from the Yuri's Toys site and connected this to an Android tablet which I use for work.  Building the voltage divider circuit and the other wiring was the first electronics stuff I had done since I built a valve radio 50 plus years ago.



I knew the Bluetooth connectivity worked and I knew that 5volts came out of the 9 pin connectors, but I don't know enough about electronics to be able to check that the 5volts coming back out of the scales had been reduced to around 3.2 volts for the main processor board.  So it was a bit nerve wracking plugging a scale in waiting to whether or not magic smoke would appear.  It worked. Yay. .  So tried the same scale in Y and Z axis ports.  Amazingly they all worked.  Just need to tidy up the case and fit Perspex light tubes so as to bring the power and comms LED's to the case lid and fit USB power connector.



The circuit board is a Texas Instruments MSP430 Value LIne Launch Pad device.  The other circuits are done use Veroboard.  Yuri has written an App to run on an Android device called TouchDRO and this is installed on tablet.

I now need to find the time to fit the scales and readers to the mill.  I am using magnetic read heads so can use the narrow magnetic strip and the thin support bracket as the Cowells is not over endowed with space.

I will try and post some more pictures when I get to the next stage.

Colin

[Jo]

  You have my interest Colin. I keep thinking Sexy could do with a DRO  .

Jo

[Twizseven]

Well after a few weeks thinking and fitting in between work I finally have a three axis DRO on my Cowells Mill.

Below are the brackets fabricated to fit to left hand side of the table to mount the X and Y axis Read Heads.



The Y axis read head on its bracket.  The magnetic strip it is reading is inside the aluminium extrusion fitted to the knee.



Rear view of table showing both X and Y axis magnetic strips



View from front of Y axis readhead




Y axis readhead and magnetic strip.



Comms Box.  This is based on the Yuriy's Toys design and uses a Texas Instruments MSP Launchpad chip. I have used Perspex light pipes to bring the LED signals to the front of the case.  The data is sent via Blutooth to a Android tablet (Toughshield T700)




And here's the display.



I'm very pleased with it.  It has fitted very neatly considering the small size of the Cowells mill.

You can see the magnetic strip sticks out from the left hand side of the table about 70mm.  This was so the read head could be mounted to the left hand side of the saddle.  By doing this I only lost 7mm of rearwards travel of the saddle.  As the vice overhands the back of the table by around 5mm I am actually only losing 2mm of movement.



Very happy.

Regards,

Colin

[Jo]

That looks very impressive Colin 

So where did you get your magnetic encoders from and can we have a link to Yuri's site 

Jo

[sshire]

Colin
Very nicely done!
I expect that we'll be seeing more tablet apps for the shop.
GTI Predictive Tecnologies has been the leader in this area. I'm sure that this will filter down to our shops before long.

<a href="https://www.youtube.com/watch?v=CpApKNhAXuQ" target="_blank">http://www.youtube.com/watch?v=CpApKNhAXuQ</a>

[sshire]

Excuse the spelling of Technologies. For some reason, I can't edit that post.

[Twizseven]

Jo,

Thanks.  The read heads and magnetic strips are from Machine-DRO (Allendale), (no connection just a satisfied customer).  I have used the 5 micron resolution heads.  They are only 10x17x52mm in size.  The mag strip is 7x 25mm two part aluminium strip.  The bottom is 5mm thick with fixing holes every 100mm.  The top section is recessed for the magnetic strip and is 2mm thick.


Yuriy's site can be found at:

 http://www.yuriystoys.com/

He produces the TouchDRO software, which is a free Android app.  There are also plans to  and instructions on building the DRO processor based on either an Arduino chip, or as I have used the Texas Instruments MSP430 Launchpad processor.  This was he first electronics building I had done in 50 plus years.  Last things I built were crystal sets and single valve radios.

He covers scales ranging from converted calipers to glass and magnetic scales.  There are also circuits to build a tacho.  I believe he is hoping to develop the circuit to handle an edge finder as well.

Regards,

Colin

[Twizseven]

Stan,

Thanks very much.

Hopefully I can now find time to go back to the two Elmers Standby engines I was trying to make before I got sidetracked on this little exercise.

Colin