Lathe Rev Counter

No multiplexing. You are right.

It was just a hint. I don't know your design. I also don't know how you will make the board. I use the Vero-wires (don't know how you call them. The isolation evaporates at about 350°C. We call it "threadle technique").

For a single shot, simplicity counts. Not the price. IMHO. Oh, and not to forget the fun! :-)

Nick

I can let you have a couple of the chips if you want them, and some LCD's as well. I'll have to find them first!

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:

'ey up Hilda, still not got that watch fettled?

That would great Peter (I want to build a portable version, current one is to be integrated into the lathe, unlike the Tachulator design which is a bolt on) No rush, let me know what I owe you.

I'll send address by eMail.

Steve

I think I know this one as "wire wrapping" the scars from my knuckles healed years ago! (Computer cards were wire wrapped much of the time) IIRC a wire wrapped connection is claimed to be more reliable than a soldered joint and has no risk of heat damage to components. Someone once did tell me the pressure exerted on the wire at the pin corners, huge number, but lost in the brain sponge.

Ironically I was thinking about soldering this up on a piece of wire wrap board. Perverse or what. I'll probably build a PCB because it will installed inside the head casting of the lathe, sight unseen so build quality is really important. (Unless I can get some wirewrapping kit locally now you've mentioned it!)

Steve

No, it's not wire wrapping. The process I mean is like this: You have some kind of pen with a thin wire spool at it's end. The wire goes through the tip of the pen. The wire (it is laquer isolated like the wire in transformers) is wound around the pin (of an IC socket) and is then soldered with a hot soldering iron. The laquer isolation starts to bubble and evaporate in the tin puddle.

Here it is! It is called "Verowire" or "Vero-wire"

If the link is a session-ID look at Products->Wiring Systems->Vero Wire

I made big prototype boards with that system. You only need a good regulated soldering iron. And patience. :-)

Nick

Swap for a working circuit/schematic, might knock up a PCB as well :-))

Working on two old 1980's designs today, originals done on a lightbox with tape...

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:

I remember that from my college days. I could never get the insulation to melt, but melting the "pen" was no problem!

Steve

Based on the 4554 or the 7224?

Steve

LOL! BTDT No, if you have a decent soldering station, crank temperature up to

Also, you don't need to solder near the pen. I wrap the end of the wire around the pin two or three times and then pull some cm of wire out of the pen, lay it aside and solder.

Nick

While you're there, if you were able to add an up/down counter for coil winding.....

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:

I think we still have the Intersil and/or the Harris data books for those, plus one of the old McGraw-Hill compendium books of electronic circuits if you want to borrow them some time. The M-H book is huge and heavy but has a lot of 'idea' stuff in it.

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:

Is that automatic detection of direction?

Steve

You'd have to gate the detector to sense which way it was running, but I was just thinking that it would be a useful feature to have, might as well do it if it is not too hard.

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:

Bigger snag is that both the 7224 and the 4554 are only up counters. I know that to reliably detect up/down you need three detectors, (imagine one hole in a disk with an opto everyturn is a count. If you have two detectors and one hole you can't be certain of direction so you need three!) but you can't go "down" with these chips! Manually or otherwise! Oops.

Steve

Like our factory and its upwards-only rent reviews...

Peter

-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:

Here are some chips + schematics that do up/downcounts: