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I'm building a pickup winder but I don't have the money to buy a good counter for it so I'm resorting to modding a calculator for this propose. Unfortunately every calculator I find has those flimsy plastic circuit boards that would melt when I solder the wires to the connections on the equals button. Does anyone know of a descent calculator I can buy or do I have to start rummaging through a second hand store to find one.

You probably need a lower wattage iron. Like a 10 watt iron. What are you using?

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Another day, another dollar.

Chad you probably noticed that you didn't have to soldier the wire
when you were locating the contact points so they could be glued
in place.

Another option-http://www.amazon.com/Digital-Photo-Laser-Tachometer-Contact/dp/B001N4QY66/ref=sr_1_1?ie=UTF8&qid=1344262344&sr=8-1&keywords=electronic+tach

The calculator for counter will probably lose accuracy around 600rpm's.

I'm not certain of the optical one function controls...and didn't see an "on" button and
no mention if one has to keep the reading control pressed but it may be a better
choice for accuracy.

Keep us posted on how it works out and good luck.

Here's some pics of my setup:







I got the calculator at Menards for $3.50. It has the "real" circuit board, so was easy to solder.

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Regards,
Phillip Patton

http://www.pattonblades.com

The bitterness of poor quality lingers long after the sweetness of low price has faded.

https://hoosierbladesmith.wordpress.com

I used a computer mouse with wire soldered to the left click button. Open your laptop calculator function and use it as your counter. Works like a charm.

I saw a simple set up once, similar to the photos but with a single cog on the edge of the wheel. The cog would hit the = key on the calculator each revolution. Just enter "+1" and start the wheel. Each time the cog hit = it would keep adding 1. Pretty simple tech but it worked.

I think the computer mouse sounds pretty solid. I'm getting ready to do this myself. Got an old sewing machine for $5. Have some magnets ready to go. All I need is some magnets to charge them with and to set up a counter.

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http://www.tinyhouseandland.com

Darrin I thought your way was great so I gave it a shot. It worked at very low rpm's
but way to slow. Somewhere around 150 and it would stop. Is that the way yours is or is there something I could do to increase it?
I'm using a reed magnetic switch wired to the mouse.

"cub" counters are cheap on ebay. They can count very quickly. Reed switch will probably be your limiter. Try an optical sensor as a trigger. This is what I'm trying to use. Just arrived today. No instructions. No English on the board. http://www.amazon.com/Amico-Slotted-Opt ... cal+sensor

I think I'd rather use a reflective sensor, but for $5.99 it was worth trying.

Mike

Edit -- Maybe I don't know what I'm talking about. Lots of stuff online talks about how fast reed switches are, but I haven't found a spec yet.

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Mike Lindstrom

No, I think you are right. Reed switches are limited by the mechanical latching of the magnetic mover to the contact. I have tried multiple switches in conjunction with both digital and analog mechanical counters, and accuracy fails well below what I would call a good winding run speed. When looking at the feedback on an O-scope, you just see a breakdown in the signal based on latching irregularities.

I would recommend hall effect circuits, or optical interrupts.

Stephen

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www.ziegenfussguitars.com

I would skip the reed switch. I soldered two leads onto the left click on the mouse, one got grounded to the sewing machine, the other lead to a wire that is contacted by the foot on the sewing machine for each revolution. If you're not using a sewing machine, the principle is the same, you just have to create a circuit somehow. Seemed to be pretty accurate up to the speeds I would be comfortable winding.

I would skip the reed switch. I soldered two leads onto the left click on the mouse, one got grounded to the sewing machine, the other lead to a wire that is contacted by the foot on the sewing machine for each revolution. If you're not using a sewing machine, the principle is the same, you just have to create a circuit somehow. Seemed to be pretty accurate up to the speeds I would be comfortable winding.