Cheap Idea for a DRO

[BillTodd]

Hi John,

Ok I found some time this morning to look at my other verniers...

There seems to have been an explosion of vernier types since I wrote the PIC code; I have half a dozen different verniers here with five different output formats! (including Mitotoyo, which is completely different) With your two that makes at least six 'chinese' formats. I have a one I bought in the USA with fractional inch display (very handy) that outputs fast 25mS pulses and, like your Aldi one, does not respond to clk or data switching.

I think the best way forward, is to drop the automatic device detection from the PIC code and add some manual set up commands and a configuration page to the VB prog. (I want to add a DRO to my Haighton at sometime so it is something I will have to sort out).

It would help, to know the switching sequences for your BCD one, so if you get the chance to work them out.... :)

Bill

[1113562]

Hi John,

Ok I found some time this morning to look at my other verniers...

There seems to have been an explosion of vernier types since I wrote the PIC code; I have half a dozen different verniers here with five different output formats! (including Mitotoyo, which is completely different) With your two that makes at least six 'chinese' formats. I have a one I bought in the USA with fractional inch display (very handy) that outputs fast 25mS pulses and, like your Aldi one, does not respond to clk or data switching.

I think the best way forward, is to drop the automatic device detection from the PIC code and add some manual set up commands and a configuration page to the VB prog. (I want to add a DRO to my Haighton at sometime so it is something I will have to sort out).

It would help, to know the switching sequences for your BCD one, so if you get the chance to work them out.... :)

Bill

OK Bill, I will do a controlled test of my BCD vernier to get the sequence and report back. I'll just code up a simple pulse generator in one of the PICs.

I'm glad you mentioned that the mitutoyo verniers have a completely different protocol as I nearly bought a 24" one a few days ago on eBay. It was mainly for the bar/PCB but using the reader would also be good.

btw. Good idea about having a manually selectable Vernier type in the VB app.

Cheers, John

[1113562]

OK Bill, I will do a controlled test of my BCD vernier to get the sequence and report back. I'll just code up a simple pulse generator in one of the PICs.

Cheers, John

OK I have done a test on the BCD vernier which is a Workzone 6" bought from Lidl or Aldi, can't remember which. I have attached an image of the state diagram.

It starts always at power up in Slow Read mode. To get from switch on to Fast Read (F.T) needs a Data then a Clock Pulse. To Zero at power up on route to F.T then its Clock then Data then Clock. When in F.T. to Zero needs a Data then CLock then Data then Clock. There are other states as shown in the diagram that are of no interest to our use I suggest.

John.

[1113562]

OK I have done a test on the BCD vernier which is a Workzone 6" bought from Lidl or Aldi, can't remember which. I have attached an image of the state diagram.

It starts always at power up in Slow Read mode. To get from switch on to Fast Read (F.T) needs a Data then a Clock Pulse. To Zero at power up on route to F.T then its Clock then Data then Clock. When in F.T. to Zero needs a Data then CLock then Data then Clock. There are other states as shown in the diagram that are of no interest to our use I suggest.

John.

This version of Vernier seems to be virtually the same state diagram as that on the YADRO site but they do not show some of the hold states.

[1113562]

Hi John,

Ok I found some time this morning to look at my other verniers...

There seems to have been an explosion of vernier types since I wrote the PIC code; I have half a dozen different verniers here with five different output formats! (including Mitotoyo, which is completely different) With your two that makes at least six 'chinese' formats. I have a one I bought in the USA with fractional inch display (very handy) that outputs fast 25mS pulses and, like your Aldi one, does not respond to clk or data switching.

I think the best way forward, is to drop the automatic device detection from the PIC code and add some manual set up commands and a configuration page to the VB prog. (I want to add a DRO to my Haighton at sometime so it is something I will have to sort out).

It would help, to know the switching sequences for your BCD one, so if you get the chance to work them out.... :)

Bill

Just to get the record straight, I found by inspection that I had reversed clock and data from the vernier to the PIC processor inputs. A BASIC SCHOOLBOY error. On correction of the error Bill's HARDWARE & SOFTWARE works perfectly with dead stable values on the PC display and also fast update rate. Its a neat and dead cheap solution if you have a PC to hand with a serial COM port.

I'm now going to sort out 2 more verniers that respond to clock and data mode pulsing so I can get X Y & Z working simultaneously. I'll then make a proper PCB for the interface rather than a veroboard prototype to make it a bit more robust. The next step will be to get it all installed on the mill with the full length PCB beams for each axis.

A big thank you to Bill Todd, he is a genius and a gentleman in equal proportions.