I'm a complete novice when it comes to Arduinos (this is my first project), but my task is relatively simple: I want to be able to shut off my laser cutter (Epilog Legend 36EXT) using my Arduino UNO and a solid-state relay.
I found this topic (http://arduino.cc/forum/index.php/topic,6460.0.html) but I'm not sure if it helps me. The cutter has a push-to-break E-Stop built in, so I'm thinking I can just wire the relay in series with the E-stop.
I'm also hoping to create a shut-off widget online using my Arduino Ethernet shield, but again I'm not sure quite how to do it. I want to be sure that this is feasible before risking a pricey piece of machinery.
Which relay would you guys choose? Do I need any additional circuitry if I choose the correct SSR? What would the code look like?
if it's an eStop then remember what the "e" is for
e is for emergency
you want the straightest, simplest, most direct, fool-proof implementation possible
if the cutter has a push to break built-in, just wire the eStop in series with it
the worst that can happen is you break a wire - and the cutter will stop anyway!
adding ethernet and and shut-off widgets introduces far too much that can go wrong
do you want your fingers under the laser while you try and debug the app?
The reason for the Arduino is that I am not in the same room as the cutter while it is in operation. I have webcams set up that monitor the bed.
As it is now, if there is a problem with the laser I have to run to the cutter and hit the E-stop. It would save 20 critical seconds if I could shut it off remotely.
Does the machine have E-Stop button that requires you to turn the button to reset the machine? If so, I think that Arduino and relay will not work. Why not get another E-Stop button?
There are lots of options. Using a web controlled Arduino to switch a relay is certainly feasible, and there is no shortage of examples of both those things.
You also have the option to use a commercial remote control system. There are also web cams with that capability built in - I have an inexpensive wireless surveillance camera with an alarm output which can be triggered via the web.
Finally, wouldn't it be simplest just to run some bell wire in to your office?
Thanks for the reply Peter. I'm hoping to avoid running 200+ feet of wire across my shop, as it is exposed and could be severed.
If I were to use a relay, what would you guys suggest? I found this diagram (Arduino Playground - HomePage), but I'm not sure what constitutes a "large" or "small" relay.
