Reading Digital caliper with Arduino

[EdK]

This thing is smaller than I thought it would be.  

Ed

   

[EdK]

Chuck,

If your digital caliper is marked Pittsburgh then it's the newer version that has a different protocol than that shown in the Instructables write-up. Here's a link to a paper Rick Sparber wrote about the HF Pittsburgh marked digital calipers.

http://rick.sparber.org/electronics/hf6.pdf

I'll have to drag out my o-silly-scope and take a look at the signals. I can make you a voltage regulator that would convert the 3.3V or 5V on the Uno board to 1.5V so you could power the digital calipers with that instead of the hokey way the Instructables is doing it.

Ed

[chucketn]

When I bought these calipers, I bought 3 pair, intending to make a DRO for the lathe.
I hope you can figure this protocol out and come up with a way to read it with the Arduino. I don't have an O-silly-scope to play with...

Chuck

[EdK]

Don't worry Chuck. Between Arvid and I, we will figure this out.

Ed

[arvidj]

I have several Arduino Nano's floating around the home office.

   

A .1 spacing breadboard with, from the left, the power adapter, then a DS1307 clock board and finally the Arduino Nano.

I must put on my reading glasses to do the wiring ... 

[EdK]

These Arduino boards are a hobbyist dream. Cheap and free development software. Open source stuff is so cool.

I dragged my o-silly-scope out of the closet but can't find the probes so I'll have to bring some home from work to use.

Ed

[Vinny]

How are you guys connecting to the caliper? I looked into connectors for it but LMS seems to be the only ones that have 'em and they want $18 for the cheapest one. Shars *had* them but it doesn't appear they still do and they haven't answered my email yet. I didn't want to solder onto mine but may have to. No need to look for my scope, it's about 10 feet away - TEK 2432 digital storage. The analog TEK is downstairs in the shop. Probes already with them. :)

[EdK]

(03-12-2015, 03:55 PM)Vinny Wrote: How are you guys connecting to the caliper?  I looked into connectors for it but LMS seems to be the only ones that have 'em and they want $18 for the cheapest one.  Shars *had* them but it doesn't appear they still do and they haven't answered my email yet.  I didn't want to solder onto mine but may have to.  No need to look for my scope, it's about 10 feet away - TEK 2432 digital storage.  The analog TEK is downstairs in the shop.  Probes already with them. :)

Those connectors are almost impossible to find. You have to purchase the expensive cable assemblies and lop one end off and put a connector on it to interface to your board. I would just solder wires to the digital calipers and put a connector on the other end to interface to your board.

I have a Tektronix 2467B, 400MHz, 4-channel scope. It seems to be working fine even though it throws an "Error 04 Test 03" on start up. That's something to do with a memory chip. I'll investigate it more thoroughly at some point.

Ed

[arvidj]

Nice scopes. All I have is a Rigol DS2072 2 channel 160MHz.

I'm a member of the Shumatech DRO Yahoo group and the subject of connectors comes up often. For a number of years the LMS connectors have been the only ones that anyone has been able to find and yes, the price is often a showstopper.

It seems like the most common solution is to dedicate the scale to the DRO by soldering to the scale connector, powering the scale from the DRO, replacing the battery with a pair of capacitors in the battery compartment and then putting what ever kind of connector on the DRO end of the cable that you happen to have in the junk box.

[Vinny]

Well I do have a caliper with an intermittent battery connection, guess it's the soldering candidate. 2467, nice scope!