Hello all,

I am building a can crusher for smashing soda cans for recycling. The building of the mechanism/machine is no problem. The problem for me is total ignorance of electronics.

I want to make a circuit that can detect the presence of the can, turn itself on and cycle through the crushing process and then turn back off.

The crusher will basically be a piston that is attached to a wheel, when the can is present the motor starts and the wheel makes one revolution (smashing the can) and stops.

Here is a link to a youtube video of a can crusher that operates like I want mine to. My design will be different but the operation-starting-stopping are exactly what I need. http://youtube.com/watch?v=NG2GwwfvB2g

I have already contacted the maker of the can crusher in the video and he will not share the wiring.

If anyone has a schematic of something similar that I can try to adapt (I will need help adapting it) I would appreciate it.

Hopefully this is a simple thing to do and I am just ignorant on the topic.

Thanks for your help,

Bob

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You need to detect more than the presence of the can, you also need to detect the absence of fingers. I notice he reached in when a can was upright.

Your circuit would only have to start the motor when the laser beam is broken and stop the motor when the gear reaches a certain position. Could do it with one latching relay. Another latching relay for the trash can (and top cover) interlocks.

He appears to have no provision for detecting cans that aren't empty. (Splash!)

 

Is a latching relay something I can get at Radio Shack? How does this relay work? He said laser in the video but it does not matter to me if it is laser or something else that detects the can.

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I think he drinks too much crap tbh. I also agree with the above his 'contraption' is going to lose him his fingers.

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Hi Bob,

I have smashed a lot of cans doing it the "German" way with a heavy piece of limber. No motor - no electronics - always working properly.

Anyway, I would skip the idea to automate the process. There are too many facts coming into the game concerning safety.

Here is my suggestion: Use the motor and mount a cam directly to the drive shaft of the piston. Use a micro-switch to stop the motor exactly after one rotation of the crank shaft. Further use two pushbuttons far apart from each other to activate the crusher with two hands only. That takes care of half-automatic crushing and operation safety. (You can't have one hand in the crusher and simultaneously push two buttons that way)

You won't have to use a latching relay for that. Just an ordinary double pole relay capable to withstand the motor power will do.

Here is the BOM for your half-automatic crusher:

1 pc. metal plate approx. 30X10" (for the main switch and the two pushbuttons)
1 pc cam for the main shaft
1 pc. DPST (main switch)
1 pc. double pole relay
1 pc. micro-switch (COM, NO, NC)
2 pcs. rugged NC pushbuttons
one handful of wires which you can salvage from your neighbor's car.

Regards

Hans

 

Thanks for the suggestions Hans.

I am just a nut for "Cool Factor" and the auto thing is cool to me.

What I did not post and maybe should have is this guys finished product. The video I referred to showed it when it was being built but the finished product is quite safe. He closed the lid on the box and built a chute to get the cans in from the top. You can just walk by and drop a can in and it crushes it and waits for the next time someone drops a can in. You would kinda have to try to get your fingers in there the way he finished it off.

Here is a link to the final product video.
http://www.youtube.com/watch?v=1qV_s...eature=related

Now I like what he did but remember, my plan is to build mine differently, I am interested in the electronics and wiring aspect only because his does what I want mine to do but mine will not stop at crushing the cans but will also go to the next step of (after there are enough) hydraulically compressing them into a large cube for recycling.

I have built all types of things and many of them are dangerous as they can be but that is minimized by knowing what you are doing while working with them. It just pays to be smarter than the tool you are using. I have a sign on my workshop door that reads:

"The tools in this shop have no brains, please use your own"

I am not worried about the automation of the can crusher hurting anyone, I will build in safety features to prevent that and it is for MY use not anyone else's.

Besides, its no fun unless it is dangerous!!!!!!!

I appreciate the safety concerns about the automation but automated is the way I would like to approach this so if you or others can help in that direction I would be grateful.

Bob

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Hi Bob,

I took a look at the movie with the can crusher in the old cabinet and also at the pneumatically driven one. (awefully loud compressor, requires maintenance)

I must say the manually crushed cans were crushed top to buttom without changing the original diameter. Getting the cans out of the machine bent they will take more room than crunched the proper way.

To avoid bending of the cans I suggest using a half pipe at the bottom and sliding (or hinged) quarter pipes closing the top via a kinematic drive during the crunch process, so the aluminum can't escape to either side.

One question about the cans: Are they standardized the same height all over the USA? (in Germany 0.33l and 0.5l cans are commonly used varying in height)

The "electronic" in the automatic can crasher seems to have been made about a century ago.

A reset switch or button is only required to clear a malfunction. (not to prepare the circuit for another can).

If you want me to design a control circuit I'll be happy to help you out. I don't know much about microprocessors and the necessary logic will be wired logic, also easier to repair in case of a malfunction. It would probably be a good idea to include a can counter to avoid pile up of the crunched cans rejecting excessive cans, (meaning crunching is stopped and the last can remains in the machine untreated) so the mechanic part won't get damaged by overload.

I suggest we chat via Skype or MSN messenger about the mechanics and the necessary sensors and switches.

Skype: hermanthegerman421, MSN: hjzelec2008@hotmail.de

Hans

 

By the looks of this You-tube sight and other related sites, quite a few folks have been successful in building an automated can-crusher. I know you can (pun intended), too!

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AllVol,

That was funny, I like it.


Hans,

I have already determined the method for crushing and it will be inside a tube that forces the can to be crushed without the possibility of it bending and jamming up the mechanism.

As for the wiring, I would want:
*Whatever is needed to detect the can and turn on the motor (it can be low voltage and operate a contactor for the motor).
*Something to make the motor stop at the end of each cycle.
*A counter would be cool (and I like cool) but not required.
*A method to detect that the receptacle is full and prevent more cans from being crushed would also be cool, but not required.
*Some LED's showing that the crusher is on, has a problem or is in the process of crushing a can would also be cool but not required.

Now, COOL is a major reason I build a lot of things and if I could get this thing to crush my can and offer me a new cold one I would.

As for the can sizes, here in the USA the majority of all soft drink cans are the same size. Recently things have changed with the market being flooded with energy drinks and HUGE beer cans. Now there are several sized cans.

I do not have the messengers setup so I will have to investigate them.

Bob

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hi Bob,

I would fit a hinged lid to the crusher, either wood or clear ploycarbonate.

Fit a microswitch under the lid.

Lift the lid, trip a mechanical switch latch, place the can inside the crusher,
closing the lid operates the microswitch which powers the motor.
At the end of the withdrawl stroke the mechanism trips the mechanical latch and the motor stops.

Finger safe and low tech.

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Bill's: www.blueroomelectronics.com/

 

As a little contribution, I suggest you to put 2 metal electrodes inside the chamber, so only a can (and not a hand, wood or other object) could close the circuit and actuate the crusher.

A 555 IC configured on "one shot" mode works as a timer and prevents the same crushed can triggering the crusher again and again if left inside the chamber (one shot per can).

The attached circuit shots a 1 second pulse, but can be modified to fit the time the motor needs to be spinning to sucessfully crush the can

At the pin 3 of the 555 you can connect a NPN transistor, a relay and your motor. I'll make a better schematic for you after dinner

pd: sorry by my english!

Attached Images

timer4.gif (4.1 KB, 11 views)

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La Rotta

 

Hi Menticol,

the circuit you suggested provides an almost accurate pulse of 1s (1.001)duration replacing the 1M resistor with 910K.

I doubt that the enamel on the cans conducts. (no sample here to prove) So I'd suggest to use an IR-barrier.

Using an IR receiver TSOP1738 and a timer circuit oscillating on 38KHz with two IR-transmitting diodes will do to trigger your suggested one-shot. I simulated it and so far it seems perfect.

The logic will be negative since the timer circuit has to be negative edge triggered. As long as the line-of-sight connection is present the receiver output is high which changes to low if the barrier is interrupted.

Hans

 

Well I think the IR barrier would be the most professional solution, but it's pretty hard to implement for a bennigner (like the OP or even I ). The bottom part of the can is not painted, so a circle-shaped metal plate divided in half would be a perfect electrode to left the can on.

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Hi Bob,

I guess there was a slight misunderstanding concerning a possible jam. You can of course take care no jamming will occur feeding the machine.

I was getting at a possible jam at its output. The container fills up with crushed cans which will reach to a certain level causing a backward jam not letting out the "treated" can. Using a fully mechanical piston there won't be enough room for the piston to travel having e.g. one crushed can and a newly crushed in its port. (Even aluminum is not compressible).

So I think it's worth thinking about that.

Here is another idea adding to the "Cool-factor". How about a row of 9 LEDs blinking from both sides to the center symbolizing the process of crunching?

Hans

 

OK people, this is why I am here.

The discussion has quickly exceeded my knowledge and you guys have already lost me. I was afraid this would happen and it happened way faster than I thought it would.

I appreciate the safety concerns and I promise I will build in safety so don't try to modify the circuit to accommodate for my lack of safety. Trust me when I am done, nobody will be able to get their fat little fingers anywhere near the crusher mechanism.

It looks so simple from my point of view to drop in a can and have things happen but your discussions so far are beyond my understanding.

I am not sure that even with a schematic I can make sense of it.

I will need a dumbed down version of a schematic.


I live near Dallas, TX and there are Radio Shacks and Fry's stores everywhere. I am sure there is some place to get what I need in this big city.

The row of LEDs suggested by Hans is a great idea but it may make it too complicated for me to build, not sure but want it if I can do it.

I have another obstacle to overcome and that is my need to get the 17 year old at the local electronics store to understand what I am asking for.

So for the sake of minimizing the amount of ignorance you guys need to overcome with me, lets start with the basics and let me get a handle on that first, then we can add in more cool factor stuff.

Due to the expense factor, I would like to avoid the laser beaming in from a satellite and sending information directly to my starting circuit that is in Australia and have the information set via internet to the China microwave tower that transmits the signal to NASA and they send a laser beam from another satellite to my can crusher that says "TURN ON" and then repeats it all again for the "TURN OFF" signal, if you know what I mean. I MUST keep this as simple as possible and as inexpensive as is reasonable.


Would you guys agree that infrared is a good method to detect the can? Is there another, better method?

Lets start here and make this decision and then go to the next step. We can build this circuit one decision at a time if that is OK with you guys. It will make it easier for me to understand what is going on. This will also create a BOM as we go so I can have a clear understanding what to buy.

Again, I appreciate you help and hope you guys are willing to accommodate my ignorance and help me do what I am trying to do.

Thanks for all your help.

Bob

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