Reading Digital caliper with Arduino

[arvidj]

(08-28-2015, 11:07 AM)EdK Wrote: Clever solution. He's using the A/D inputs thus not needing the level shifter circuitry.

Ed

I would think that having a level shifter at the scale end might offer an enhanced level of noise resistance. But careful placement and shielding might take care of that issue when taken off the electronics bench and put in the shop.

[EdK]

(08-28-2015, 02:36 PM)arvidj Wrote:

(08-28-2015, 11:07 AM)EdK Wrote: Clever solution. He's using the A/D inputs thus not needing the level shifter circuitry.

Ed

I would think that having a level shifter at the scale end might offer an enhanced level of noise resistance. But careful placement and shielding might take care of that issue when taken off the electronics bench and put in the shop.

I agree and I would never connect directly from the caliper to the Arduino like he did. Any ESD is going to blow out the Atmel chip rather than a 35 cent transistor. Ideally, opto-isolators should be used but transistors are cheaper and easier to replace.  

Ed

[chucketn]

I have found a Hall effect switch based tach sketch for the Arduino, and modified it to display on a 16x2 LCD. I chose hall effect because that is what I use on the DRO-550 on my mill, and had ordered 2 switches when I built it. I will build it up with a dedicated Arduino and add it to the DRO-550 setup so I don't have to swap out an axis display to use the tach.
I plan on combining this with the HF Scale reading sketch to make a simple DRO setup for my lathe. I will share the sketches if anyone is interested. Didn't really need the tach on the lathe as mine has a tach built into the control box.

Chuck

[EdK]

Chuck,

I'd be interested in the sketches.

Ed

[chucketn]

I found a sketch that will read the HF Calipers! I had to build a level shifter from 2N2222a transistors and 10k ohm resistors for the caliper clock and data.

The sketch came from here:

https://sites.google.com/site/marthalpro...al-caliper

As written, it reads the caliper when in mm mode, and displays on the serial monitor.
Changing the line(5th from last) to

result=(value*sign)/100.00

to

result=(value*sign)/2000.00

changes the output to inches. You would also change the associated Serial.print1n(" mm") to Serial.print1n(" in"). I will eventually add an if statement to do that based on what unit value is in the data stream. I have not figured that out yet.
I need to also add the Bluetooth back in to try and get it to talk to TouchDRO.I have miss placed my final working code. When I find it I'll post it.

Chuck

[animal]

hi there , new guy here . Found you folks while doing a search for a Arduino DRO , very interested in this thread . is it still a work in progress ?
tks
animal

[EdK]

(09-25-2017, 05:04 PM)animal Wrote: hi there , new guy  here . Found you folks while doing a search for a Arduino DRO , very interested in this thread . is it still a work in progress ?
tks
animal

 to the forum animal.

Ed

[Vinny]

Welcome to the forum, Animal. I think the post above yours was the end of that one.

I've been kicking around the idea of using a rotary encoder for a dro on my mill. I saw a mention somewhere where a guy used a belt with a rotary encoder on his mill and said it worked well. Unfortunately he didn't elaborate but someone else chimed in with some calculations that showed the LPD3806-1000M encoder could get you 0.0001 accuracy but he wasn't using a belt. Just for proof of concept I picked up a 400M to try, but before the belt and pulleys showed up I ended up using the encoder on another project - so I have to order another one (hopefully the belt and pulleys won't get used before it gets here!)

[Vinny]

Found it: https://forum.arduino.cc/index.php?topic=313713.0 I guess he did elaborate. Comes complete with pics, although only the slideshow works thanks to photobucket's new rules. The accuracy calculations are in a different post tho.

[animal]

tks Vinny , I was wanting to go the Arduino/ cheap caliper route . I saw that they got so far in this thread & then chuck came back with the last post . I don't know what the pull-up's resistors would do or where they would go ? I was liking what I was readin . but this Arduino stuff is all new to me . if it was a bolt or a motor I could figgure it out 
tks
animal