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Turn your Trav-A-Dial into DRO kit proposal

I've been learning about encoders. All the DROs use some kind of encoder. There many encoder schemes. I like Trav-A-Dials because I can watch the needle go round and round lots easier than watching a digital display increment. On the other hand a digital display doesn't suffer from parallax. Best is both. So, after a little research I figured out how to add a digital encoder and display to a Trav-A-Dial. This mod would require reversible modifications to your own Trav-A-dial that anybody here could do. It could be set up to be battery operated with the digital display located at the Trav-A-Dial and a battery life of about 150 hours. Or it could be set up with a remote digital display connected by a cable to the Trav-A-Dial. The remote display would be powered by a wall wart. The display would NOT remember where it is when the power is off, such as when changing batteries. Anyway, it looks like I can retail these things for around $100.00 US. If demand was high enough this could be lowered substantially. So, anybody interested? Should I try to develop this? Thanks, Eric R Snow, E T Precision Machine

Reply to
Eric R Snow
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Please think about including a hold-up capacitor in the power supply circuit that'll keep it going at least for a while -- having a power line "blip" reset the thing in the middle of a cut would be a royal pain.

Reply to
Tim Wescott

Would this include the encoder and the display, or just the cost of the modification. We are looking for a dro for our bridgeport clone but can't afford the $1000 price tag for a decent one.

Reply to
woodworker88

Greetings Tim, I would have some sort power backup that would last a minute or two. I was thinking of maybe a lithium coin cell that would give many minutes backup. But thanks for the suggestion. It's a good one. Eric

Reply to
Eric R Snow

This would include the display and encoder. You would need to supply the Trav-A-Dial. If you are looking for a complete system look at Jenix. Two axes. .0002 resolution. An outfit called LMSC sells them. Follow this link:

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price is less than 700 bucks. Anyway, this is just a proposal right now. I have looked at all the parts required and quoted the machining like I would a job for someone else. So even if I started making them tomorrow it would still be at least a month before any would ship. Eric

Reply to
Eric R Snow

Not that I'd like to have one (for now). But I'd like to integrate it into my YADRO-project (a DIY-DRO). If you see any chances that we agree upon a protocol, I'd like to make the additions to my software.

YADRO can be found here:

Enjoy

Nick

Reply to
Nick Müller

Greetings Nick, It looks like, to me, that your scale reader will not work with the encoder I would use just because the signals are different. The encoder pulses are simple: A high, B high, A low, B low. High is +5 volts, low is zero volts. When spinning the other direction B leads A. So the display knows whether to increment or decrement the number displayed. That said, I'm no electronics guy but you can probably use your display scheme with different inputs. Since it is software driven that should be easy for you considering the work you have already posted about YADRO. My scheme for counting can all be done with logic circuits. There is no absolute position from the encoder. And I have to look at the spec sheets of various devices and sample circuits to come up with electronic designs. Cheers, Eric

Reply to
Eric R Snow

Yes, what you have described is a quadrature encoder. This would require a different (or modified) digital interface. If you look a shumatech.com there is such a interface. It reads from a quadrature encoder and on the other end behaves like a chinese scale. That's what uC are for and very good in. You should have a look at them. Big fun! Sell your

74xxx-collection at eBay. :-)

The good old TTL-times. Do they still exist in underground? :-))

That doesn't matter. The chinese stuff neither has. You always have to set a reference point.

But coming back to your TTL-grave (as we call it). How's the output? Do you intend to directly drive 7-segment LEDs (or such)?

Nick

Reply to
Nick Müller

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