Autogate update (lots of pics)

[Alan in Little Washington]

It has been awhile since I gave an update on this evolution. As shown in my previous post and the first pic below, I modified one of my manual gates with the addition of a pneumatic actuating cylinder. The design worked fine so I modified the remaining gates.

Since that time I changed my installation plans, however. I decided I did not want to initiate gate opening using machine power directly. Instead I will use current sensing switches wired to each electrical outlet providing power to the machines. Also, instead of mounting the blast gates on each machine, I decided to install them and all the wiring and plumbing behind the knee wall or, for the mid-floor tablesaw and jointer, in the duct that runs along the garage ceiling below the shop. The only thing visible will be the flex connecting the machine to the DC port. To make room for and install the auto gates, I needed to raise the ports and rework the ducting behind the knee wall. I also ran 4" duct to the ceiling for a planned tablesaw over-blade dust pickup. In keeping with the clean design of my shop I opened up a slot in the ceiling drywall to run the duct.

I have also been trying to find and collect inexpensive parts for the system. I had a setback finding inexpensive current sensing switches. Ones that I thought would work that I found on Ebay at a decent price were not as advertised. Despite help from my brother who is an EE we were unable to make these units work or construct new ones economically. I will be using current sensing switches available from an electronics supplier so the cost of my gates has gone up a little. The actuator, current switch, solenoid valve, misc. buttons, pilot lights, etc. is running about $40 per gate. I guess, that still is not too bad when compared to the cost of EcoGate brand autogates which can run $200 - $300 for just a 6" gate.

Here are some pics:

An autogate mounted on a machine. In the final installation the gate and the plumbing will be behind a wall and not visible.



Four port knee wall before relocating the three low DC ports.



Low 6" and one low 4" port have been moved up. One port was eliminated. The old port holes in the drywall have been repaired. The new electrical box blank cover plates will eventually have an autogate pilot light, a manual on/off switch, and an electrical outlet selector rotary switch. All the autogates are just behind the port openings- gate slide is dark and visible.



Light fixture temporarily removed and ceiling opened up to run over-blade DC duct.



4" pipe installed.



Closing up the slot.




Ceiling repaired except for paint and light reinstalled.



DC port for over-blade dust pickup and autogate control wire - when the lower part of the over-blade pickup is folded out of the way, the servicing autogate will be disabled via a microswitch at the hinge point.



Finishing up the last knee wall- ports raised, one port repositioned, and autogates mounted. Old holes awaiting repair.

[toolman]

It's looking GOOD Alan!

[toolferone]

Just when you think the shop is done! This is why most say that the workshop is never done. Looks good Alan, that's a lot of work/fun.

[Trent Mason]

pneumatic actuating cylinder

Is that similar to the FLUX CAPACITOR?



Just kidding. Alan, your shop is nicer than my house. Very impressive!

Trent

[MikeH]

That is awesome Alan. I would have NO IDEA how to do any of that.

[RandyJ]

Nice work, Alan! That doesn't look like a workshop, it looks more like a science lab!! Way too complicated for my simple mind.

[McRabbet]

Looking good -- I'm sorry to hear that the current sensors from eBay didn't pan out -- they looked promising. I'm not sure if you subscribe to Woodwork magazine, but I searched back through my old copies and found an article (Issue 91, pg 41) by a Robert Reed that uses a current sensor at each tool to generate a low voltage signal out to a common pair of wires between tools back to a Dust Collector control that senses a voltage on the two-wire bus and transfers a voltage to a triac which enables voltage flow to the dust colletors itself, turning it on. I had looked at it and even did and estimate of the parts costs -- about $10/tool for ten tools (it takes advantage of price break for the current sensor - an Amveco Magnetics TE1005-ND which are $7.80 each or $6.50 each in qty 10 and $7.98 for the Teccor Thyristor Q6025P5 Triac, from Digi-key).

For folks that want a simple blast gate switch system to turn the DC on (like the system sold by Penn State Industries), he had a follow-up article in Issue 98 that used a set of normally open microswitches on each blast gate that tie to a 2-wire bus from gate-to-gate and back to a low-cost 12 V DC relay powered by a wall-wart (as Jim Murphy calls them) transformer. The relay is less than $10 and the switches about $2 each. If anyone is interested, I can provide a copy of the articles.

[Alan in Little Washington]

Originally Posted by McRabbet

Looking good -- I'm sorry to hear that the current sensors from eBay didn't pan out -- they looked promising. I'm not sure if you subscribe to Woodwork magazine, but I searched back through my old copies and found an article (Issue 91, pg 41) by a Robert Reed that uses a current sensor at each tool to generate a low voltage signal out to a common pair of wires between tools back to a Dust Collector control that senses a voltage on the two-wire bus and transfers a voltage to a triac which enables voltage flow to the dust colletors itself, turning it on. I had looked at it and even did and estimate of the parts costs -- about $10/tool for ten tools (it takes advantage of price break for the current sensor - an Amveco Magnetics TE1005-ND which are $7.80 each or $6.50 each in qty 10 and $7.98 for the Teccor Thyristor Q6025P5 Triac, from Digi-key).

For folks that want a simple blast gate switch system to turn the DC on (like the system sold by Penn State Industries), he had a follow-up article in Issue 98 that used a set of normally open microswitches on each blast gate that tie to a 2-wire bus from gate-to-gate and back to a low-cost 12 V DC relay powered by a wall-wart (as Jim Murphy calls them) transformer. The relay is less than $10 and the switches about $2 each. If anyone is interested, I can provide a copy of the articles.

Those are similar to the prices I found. My problem is I am trying to control each autogate solenoid with its own current sensor switch so I needed 11 full up current sensor switches (the alternative is a PLC like EcoGate). By the time we added up the cost of a ferrite toroid, a few more parts- misc. resistors, capacitors, triac (or FET), etc. and an etched or vector circuit board, it is just wasn't worth the hassle nor economical. Especially when I can get a current sensing switch which is rated to directly control my solenoids from DigiKey for $18 ea. (if I buy 10). I found a source in China for a similar unit for only $12, but am a little leery of that route. I would still be interested in seeing the Woodwork article, however.

EcoGate has a new clip on sensor- that clips over the full power cord, you don't need to split the wires and run only one conductor through the toroid like most current sensing units. I don't know the cost but it looks neat, unfortunately it won't directly control my solenoids!



To turn on my DC I will be using a little magnets mounted on the gate slides and small, glass, magnetic reed switches I picked up on Ebay for pennies. The switches will connect to my LVC start circuit.