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JCDammeyer's 42 projects

jcdammeyer said:
And finally got around to 3D printing a 'poop chute bin'.

Poop Chute Large Magnetic for Bambu Lab X1 Carbon by V3 Precision | Download free STL model | Printables.com

This is a poop chute for the Bambu Lab X1 Carbon. This is a larger size than the previous version with two magnetics | Download free 3D printable STL models
www.printables.com www.printables.com

I've been using an old ice cream container but it's wider and loose. This new one is held on with magnets and doesn't stick out as far as the external spool holder which can still hold a spool above it.

Chalk another one off the list of 42 things to do. Only 42 left...
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And I was worrying earlier today that at some point you would be electrifying and computerizing a toilet. Desjavu ? Mrs. D must be quite a lady. :rolleyes:
 
jorogi said:
And I was worrying earlier today that at some point you would be electrifying and computerizing a toilet. Desjavu ? Mrs. D must be quite a lady. :rolleyes:
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Not yet. But there are some pretty cool bidet add on things for toilets. Do we want Home Assistant to know what we are doing in there?
 
I think you have more stock than your local mini-motor control warehouse.
Be ever so careful with those POT assemblies.
I bought a few last year and the soldering points crack easily.

The AliExpress supplier did replace a few of them for me, when I complained.
 
LenVW said:
I think you have more stock than your local mini-motor control warehouse.
Be ever so careful with those POT assemblies.
I bought a few last year and the soldering points crack easily.

The AliExpress supplier did replace a few of them for me, when I complained.
Click to expand...
POT assemblies?

The stuff in the box is all at least 50 years old. A friend and I cleaned out someone who was closing down. We sold the electrolytic capacitors to a Radio/TV repair shop (remember those) in 1974. The rotary switches are all silver plated contacts so there's tarnish since they aren't wrapped in plastic. I need to sped some time creating an inventory of what I have there.
 
I saw these items from Amazon on that you had.

They look very much like some potentiometers I bought to control the speed of some mini DC motors that I had put into an actuator setup.

1741113167930.png
 
LenVW said:
I saw these items from Amazon on that you had.

They look very much like some potentiometers I bought to control the speed of some mini DC motors that I had put into an actuator setup.

View attachment 60890
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Ah! Nomenclature issue. These are Potentiometers:

1741113827684.png

Used with say my little DC motor controller that puts out a PWM power drive for just unidirectional motor control.
1741114226719.png


The motor drivers I ordered require a processor to produce the PWM signal and direction control. Taking feedback from an encoder lets it then adjust the not only the speed but the position.
 
Yes, I ended up getting ‘Pulse Width Modulators’ as well.
I like the fact that there is less wasted energy to heat.

But I may be talking out of terms, I am a mechanical technologist.
My son (Electrical Controls Specialist) would be able to translate.
 
LenVW said:
Yes, I ended up getting ‘Pulse Width Modulators’ as well.
I like the fact that there is less wasted energy to heat.

But I may be talking out of terms, I am a mechanical technologist.
My son (Electrical Controls Specialist) would be able to translate.
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This was a pretty simple unidirectional circuit. Used an LM555 timer to create the PWM signal and that drove a FET capable of handling 200V and 18A at 25C or 11A at 100C.
We did a group purchase of parts and boards back in 1998 and everyone who contributed got on. I've used it to spin a medium size DC motor to turn a Honda CAM pulley for testing sensors for a multi-port injection and CD ignition. Same with testing a disk with a slot for the Electronic Lead Screw. Now the parts alone would probably cost more than a complete module from China.
 

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The reason for the motor drivers and one of the stepper motors from the old 3D printer is to motorize this filament winder borrowed from JoeMac.
The Bambu printer prefers plastic spools to the paper ones but it's pretty tedious to rewind a 1kg spool. And although Joe redeisgned the feed guide to move more slowly across the take up spool width we both feel a stepper motor would do it better and a DC motor to spin the takeup. The rag under the supply spool is to provide drag. Otherwise the supply over spins.


1741123875212.png
 
The five little motor controllers just arrived. Odd that they are marked as 12V for the motor voltage. The device itself is good to 46V. I was planning on 24V. It does have a 78M05 (5V, 500mA) regulator but even those are generally good to 35VDC in. However the biggest issue is the input filter capacitor rated at 25V.


Here's the basic circuit from ST Micro.

1741136145272.png

Where ST Micro suggests 0.1uF (100nF) these boards have 220uF, 25V. Not having a low value like 0.1uF results in more electrical noise and mucks up the drive signal a bit. Also most 78x05 series like to have 0.1uF or 0.01uF across the input and output to ground close to the package. Again to handle dynamic response better.

The 78M05 output also is brought out to run say a small Arduino and there's even a jumper to enable that 5V regulator so an external supply could be used. However then the output of the 5V regulator is back driven from the external supply.

The control signals are all there but one has to also attach to the ground screw terminal. Again it's a bit klutsy.

So these little boards (about $5 each after taxes) are fundamentally flawed which is why they are so cheap. But we also know that the L298N is $18 in singles from Digikey.
 
OK. Here's why these little motor controllers are real sh_t.

The driver can measure and limit current with a current sense resistor. They've made the resistor 0 Ohms by connecting the pin to ground so that there is no current limit and hard to retrofit. No bypass capacitors for electrical noise suppression and hard to retrofit. The data sheet is quite explicit that a 100nF cap has to be on both the VS and VSS pins.
Also they have used an equivalent to a 1N4007 diode with a reverse recovery time of 1500nS. The data sheet suggest fast recovery diodes in the <200nS range and given that the driver can supply 4A a 1A diode may be a bit small.
The big filter caps are really too low a voltage for a 24V motor.

So what to do?
Well first I'll create an updated schematic that shows how it should have been constructed. Then I'll see if I can modify a board to match the drawing.
 

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jcdammeyer said:
The reason for the motor drivers and one of the stepper motors from the old 3D printer is to motorize this filament winder borrowed from JoeMac.
The Bambu printer prefers plastic spools to the paper ones but it's pretty tedious to rewind a 1kg spool. And although Joe redeisgned the feed guide to move more slowly across the take up spool width we both feel a stepper motor would do it better and a DC motor to spin the takeup. The rag under the supply spool is to provide drag. Otherwise the supply over spins.


View attachment 60900
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Can you print rims for the cardboard spools?
That's what I do for the Anycubic and it works great.
 
OK. It's late now so I'm not going to do anything to the board but
David said:
Can you print rims for the cardboard spools?
That's what I do for the Anycubic and it works great.
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I tried that with a drawing from M3. The problem is that this version of the AMS has the sides between each reel sloping in. So the rims end up rubbing because the cardboard is already quite wide and the filament jams.
 
It's too late tonight to do anything mechanical to the boards but here's the updated schematic. Biggest change is the correct capacitors near the device. Voltage changed on the electrolytic capacitors and finally changing the diodes to Schottkey which are much faster and will suppress the reverse voltage allowing better and more stable speeds.
It will be difficult to bring the sense line out to limit current on this board. But if the L298N isn't a fake or discard device it would be possible to make a new PC board that used most of the parts on this existing board but allowed additional control. Probably not worth the effort.
 

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jcdammeyer said:
OK. It's late now so I'm not going to do anything to the board but

I tried that with a drawing from M3. The problem is that this version of the AMS has the sides between each reel sloping in. So the rims end up rubbing because the cardboard is already quite wide and the filament jams.
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I'll send you the STL file that I use. They are very thin.
 
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