Connecting a mech endstop with long wires

Hi

I want to discover when one of the blast gate in my dust control system is opened and then start the dust collector. When the blast gate is closed the fan should stop.

My current plan is to mount a mech endstop on each of the four blast gates. When a blast gate is opened the endstop will be pushed and signal an arduino. The arduino will then trigger a 10A 250VAC relay that will control the main power to the fan (the fan is 7,7A so that should be OK electrical wise).

I have made a test circuit to verify the logic, and it seems to work.

But... I will have to run wires from the dust collector, where the arduino will be located, and to each of the dust ports. That will be up to 10 meters.

I'm wonderings if the arduino will be able to receive the input signal from the mech endstop over such a long distance?

Is there any battery powered unit that I could use to discover that a blast gate is opened instead of the mech endstop that requires, so that I could avoid dragging wires to each of the blast gates?

I'm wonderings if the arduino will be able to receive the input signal from the mech endstop over such a long distance?

Yes, no problem. Use twisted pair wiring (signal and ground), and low value pullup resistors (1000 Ohms or less) to the signal lead, at the Arduino connection.

If there is serious electrical interference, you might have to run shielded twisted pair wiring, which is more expensive.

Wouldn't a simple microswitch do the job? Why bother with an arduino?

Allan

allanhurst:
Wouldn't a simple microswitch do the job? Why bother with an arduino?

Dragging 110V wires around a workshop and protecting them properly would be more expensive. You could run a ~5V circuit through the microswitches that could activate a 110V relay near the dust collector, however.

OP, take a moment to see if it's possible to mount the microswitch so that when the gate is closed it will depress the switch. Then it's just a matter of using the switch's "normally closed" (NC) pins instead of the "normally open" pins and reversing your logic.

First, I already have an arduino nano, a 5v relay and some end stops from a earlier project.
This kind of relay: 2-Channel 5V Relay Module | SainSmart – SainSmart.com
This kind of end switch:
Laser-trade.de

These are designed to work with arudino (5v +signal) and all the parts cost next to nothing - thus the simplest and cheepest solution for me seems to use these parts.
So if long cables will work I only have to run 5V signal wires around the shop. I think that is important.

Jremington: I will get me some shielded twisted pair cables. As the cables will runnalong steel pipes and there are quite some machinery I guess that will be the wise thing to do.
Thanks for all your input. I will report on how it works when Inhave it up and running.

jremington:
Yes, no problem. Use twisted pair wiring (signal and ground), and low value pullup resistors (1000 Ohms or less) to the signal lead, at the Arduino connection.

If there is serious electrical interference, you might have to run shielded twisted pair wiring, which is more expensive.

Just a short follow up on this.
The end switch has 3 input. Ground, 5V and Signal.
When using a shielded cable, should the shield be connected to ground? So that there would be a shielded cable with 2 wires.
Or should the shield be connected to something else so that there would be a shielded cable with 3 wires?

If the shield is not connected to ground, what should it be connected to?

The shield in shielded cable should be connected to ground at the Arduino end only. The two wires inside should be twisted together to avoid interference by magnetic induction.

Skip the twisted or shielded cabling; you can easily eliminate spurious signals with zealous debouncing and even a full second of delay between the switch closing and the relay being activated should be acceptable (even convenient). I'd be more worried about static discharge instead.

you can easily eliminate spurious signals with zealous debouncing

No, you cannot, particularly steady state signals induced by magnetic fields or frequently recurring electrical impulses (quite typical in an industrial environment).

My brother uses a remote control clipped to his shirt to turn the vacuum on/off in his woodworking shop. When on, you can hear if any gates are open that should not be. Much easier solution!

Paul

I currently have a remote control, however I constantly find that I have to walk over and check if any gates are open - and I do not hear if another one is open or not.
I think a solution where I open a gate and the dust collector starts, and when I close it it stops seems as a better solution. Then I always know that there are no open gates, except the one that is causing the blower to run.

But I have a different - more practical question.
I have these:

Does anyone know where I can get plugs and more what kind of plugs to get?

I would prefer to be able to have a plug at the end of each wire so that I do not have to solder everything on.

That might be a JST style connector. The one view you posted does not give enough information.

Does this help?
(ref. attachment)

Also, it seems like this is said: .“It uses a standard 4 pin, 100” pitch header and accepts a standard, old-style CD-ROM audio connector cable"

But I’m not able to convert that into some kind of connector that I can find and order

More likely 0.100" pitch.

This is extremely common. The headers on the Arduino are all 0.100" pitch. If you aren’t too concerned about exact fit, then buy a bunch of Arduino headers and cut one down to 4 pins wide.

If you want the exact connector, then start searching on Mouser or Digi-Key. Enter the pitch and the number of pins and it should not take too long to find one that looks like it. Then you will have the name of the “series” of connectors and you can go looking for the mating half for that series. (None of the big retailers seem to have twigged that the most important information about a connector is “What plugs into this?”)

Here are some JST cables that you could just splice your cables onto the existing wires.

Thanks Chagrin, but I found the connectors.
For anyone wondering, the correct connectors are JST XHP-4.

Example: http://www.digikey.com/product-detail/en/jst-sales-america-inc/XHP-4/455-2267-ND/683353

I have got some and they are a confirmed fit.

Thanks for all your great input!