Project using a Propeller 1- Semi Automatic Pneumatic Can Crusher
Jim Fouch
Posts: 395
This is by no means pushing the limits of the Propeller, but just something I made for the fun of it....
Comments
You would think common sense would prevail, but sooner or later someone will come along that won't understand how it works or how it's triggered and it could end badly.
Once I get the auto loader set up you won't have access to the crushing area.
Not even sure that will the auto loader will work out as every twenty or so cycles a can will get crushed in a weird way and jam it it up. That will be a pain to clear as you will need to gain access to the crush area. So, I may add additional beam interrupters and detect if an obstacle (ie... someone's hand) and stop the process.
But as it stands right now, it's about as safe as running a chainsaw on the top rung of a ladder.
For ultra safety you can stop the process if one of the buttons is released before the cycle is complete.
On the end of the gear box shaft I have a large bolt that I sawed the head off of and drilled a hole down through the center to fit the gearbox shaft. Inside the large PVC is a smaller diameter PVC pipe used as the ram that has a groove milled along the length of it. Inside that is a bicycle brake cable that is wound around the threads of the large bolt and the cable is then tightened from end to end of the inner PVC pipe. As the bolt turns one way it winds the cable on one end as it unwinds at the other end and vice-versa when it reverses. I got the idea from an old floppy drive mechanism that had a thin metal strip with a groove in the middle that would wind and unwind as the carriage traversed. I can't remember what that type of drive is called.
So you'd put a can into the Y of the PVC pipe and press the start button. The motor would run and then crush the can against the end of the large PVC pipe. As the motor would stall out at the end of the crush the current relay (from refrigerator compressor) would trip and then energize the DPDT reversing relay which then reversed the motor. The ram would then retract letting the crushed can fall through the slot at the bottom and continue on until it reached the limit switch and then turned off. It has crushed a lot of cans. I had ideas of automating it further but never bothered.
it for 2000N max force, based on estimating the weight a can can hold up when you carefully step on it!
2000N is not always enough at low speed, but at full speed of my crusher its pretty reliable.
The safety issue is similar, but it takes about 3 to 4 seconds to operate which is less scary without
any guard - however releasing requires the motor to be reversed and the gearing makes that slow
by hand!
When complete it will have sliding doors like a lift and an interlock on the doors. The plan was to play
suitable audio clips during the crushing with an mp3 module to make it fun to use.
ebay.com/itm/12864-128x64-Serial-SPI-Graphic-COG-White-LCD-Display-Module-LCM-w-ST7565P-5V-/122179960272?epid=1492107959&hash=item1c727e3dd0:g:XTIAAOSwIgNXq9Z5
I have a driver I wrote that uses PASM to transfer the bitmap to the display if you want a copy let me know. It uses a SPI buss and is very fast.