Emergency shutdown method

[quinnf]

Bruce,

The failsafe aspect was what hooked me on using air.  I have a nailgun compressor that's tighter than a frog's . . . uh, meaning it doesn't leak appreciably over the month intervals that I'm away from the wife's place, so I figured I'd put it to work when I'm not nailing nails or blowing pine needles and/or sawdust out of the groj.  Will likely set it up on a dedicated circuit and have it turn on once/day in case it starts to leak and I'm not there.

And I've recently gotten an Arduino board and have been experimenting with turning on and off LEDs and transistors.  Lots of apps out there, and so long as it can turn on and off relays, it will serve my needs.  So I think that's the way I'll go for a control system when I get there.

Like you, I wanted to keep things simple and maintain manual capabilities at all costs.  But when it's below freezing the 'roid takes some cranking to get it to light, so I didn't want to chance running out of air.  Also invested in a Jetta glow plug and drilled the dummy plug.  I'll eventually get around to doing the automatic shutdown controls, etc.  But for now I want the wife to be able to walk outside 50' to the groj which will be illuminated by a 4W LED emergency light run off the starting battery, turn on a power switch which will energize the 12V bus and enable the air solenoids, then hit the glow plug switch, start switch, RUN switch, then let go of everything when the music starts.  And when voltage appears on the control board, a relay will connect to the line going to the manual transfer switch INSIDE the house and she can turn whatever circuits she wants.  If she forgets to shut off the genny prior to killing the engine I'll have that covered, too.  Thee aren't any large appliances, so I think that should cover it.  Mainly want to have the gas heater blower (1/4 HP) 'fridge and lighting work.

Quinn

[carbon-rod]

Quinn,

How do you find the Arduino so far? they are extremely popular these days for people just getting into electronics, I think the PIcaxe that Bruce uses is pretty much a similar concept from a different manufacturer.

The arduino is plenty capable of running relays etc and once you get into the hang of it the world is your oyster... You will find yourself getting excited and automating a lot of stuff then! your mrs will end up sitting inside the house and just pushing a single button in no time

[quinnf]

The Arduino is really neat.  I had been thinking of putting something together using discrete components, but when I read a little about the Arduino, I realized the microprocessor can do an awful lot of things that you just can't do with transistors, resistors and caps, which is the limit of my rudimentary knowledge of electronics.  And there are so many geeky people out there doing stuff with them, it's pretty easy to find plans and sketches (programs) for things like thermostats, motor controllers, tachometers, and the software has decision-making capabilities, if-then, if-then-else, etc.  And a board is only about $25 and everything is open-source.  So I'm pretty happy with what I've seen so far.  I don't want to buy a controller, in fact I don't want one if I can't do it myself.  That's the thrill/joy/buzz I get from doing stuff like this. 

Just Google whatever app you're interested.  For instance "arduino tachometer" gets you pages of applications and YouTube videos showing how folks have done it:  example:  http://www.youtube.com/watch?v=rmCNe7kJAe4

[carbon-rod]

I agree the amount of electronics required to be able to come close to a microcontroller is just crazy, they are so versatile and if you want to add new functionality its so easy to do without having to re-wire everything...

I'm going to attempt to determine the speed of my engine (when I get it) by looking at the AC output from the alternator. I will step it down using a small transformer so it's in a workable voltage range, and then use a fairly simple circuit which will send a digital pulse into the microcontroller which I can monitor and vary the output speed from there...

I also wouldn't want a controller on the engine that I couldn't build myself.. It's just so much more fun and also you can design it and make it exactly how you want rather than having to put up with the shortfalls of a purchased controller..

[BruceM]

Quinn- I found some air pressure sensing switches at Grainger which could automatically start your lovely compressor only when needed.  I would have liked an analog pressure sensor, but they were hundreds of dollars.

I agree the Arduino's are a bargain, very capable, and the support base is growing. A very good choice for a hobbyist project.   Of course I'm still very fond of the Picaxe chips, since I "cut my teeth" on Basic in the mid 70's. (It's the same as Stamp Basic, with some extras.)  

I have a project I'm working now that I may use a Teensy AVR board for, using it's USB interface. It's a "fly off" between that and a PIC USB development board- to see who's software is easier to cope with for me.