cool. In the old days I would have had most of the parts flating around, but
after my dad died, I had to clean out his basement, and just didn't have
space for all the random scrap...... sold off pretty near a truck load of
electronic parts to an electronics salvage shop. Last time I was there, the
2" nixie tubes were still on display (its been about 5 years since my dad
died...)

Didn't think my idea was anything novel, but figured it might spark some
interesting discussion..
thansk
--JD

BRuce wrote in message news:1072783813.16901@sj-nntpcache-5...
Well, I don't think your idea is revolutionary as I have had the same
setup for more than 2 years. I made my "microswitches" and had the
relay in my junk pile so the cost was just in the wire. I don't think
you will need a delay as there is a human delay between finishing a cut
and closing the blast gate, plenty of time to clear the duct. if not
count to 3 then close the gate.

BRuce

jduprie wrote:
Hey folks...
as part of the "new shop" I scored an oneida 3HP commercial dust
collector (VROOOM - drive by #1)... The problem is, the shop is 40X50
feet
(thats number 2), and its a real drag walking all the way over to the DC
every time I need to turn it on or off.

Here's my solutution:
buy:
1) relay of the right size for your DC (Get one rated for low
voltage DC for the coil size - I'm using 24VDC)
2) one transformer to provide the DC current
3) one "micro switch" for each of your blasst gates (there
should be
a blast gate at each tool) The micro switch is just a small switch with
a
long spring loaded arm. When the arm is pushed, the switch closes.
4) enough thermostat wire to run from the DC to all of your
blast
gates

set up the transformer, and wire your DC power supply through the relay.
hook one of the legs of the transformer to one of the legs of the relay
coil, and the other to the red side of the thermostat wire. Hook the
white
side of the thermostat wire to the other leg of the relay coil. run the
thermostat wire to the closest blast gate. Leave a couple feet of wire,
and
run another length to the next blast gate. Continue until you've got a
wire
going to all of the blast gates.

Now you need some way to mount the switch to the blast gate. First
of
all, figure out the best way to mount it to make it work. it should be
set
up so that when the gate is opened, it pushes on the switch arm, and
closes
the switch. If you've got plastic blast gates, you can drill holes to
mount
the switch (be carefull not to do something that prevents the gate from
opening...). If you've got metal gates, you can drill them as well, or
if
you've got metal gates that can be disasembled, you can use the bolts
that
hold them together as mount points (this is what I did).

I made brackets to hold the switches out of cheap hardware store bar
stock metal (I think it was 1/2 by 1/8). Cut it to length (in my case
about
3"), and drill holes to match the mounting holes in the switches and
whatever method you're going o use to hold the switch to the blast gate.
Go
bolt all the switches to the blast gates, and make sure that the gate
closes
the switch when the gate is open (a continuity tester is usefull here).

attach the wires to the switches, testing each one as you complete it.

If its working right, every tim eyou open a blast gate, the DC will turn
on.
When you close the blast gate the DC turns off.

My total system (10 gates) cost about $50 US, and took about 3 hours to
install.....

--JD



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BRuce