Stopping mechanism for DIY tape cleaners?

[ge0dude]

Hi, I think this is in the most appropriate category, if not, feel free to move or delete.

I'm thinking about building my own tape cleaner that I could 3D print and hopefully share with the community if it's good enough.

I've seen some really cool examples, but from what I've seen, they manually slow down and stop the motor at the end as to not cause any blowout. Is there some sort of circuit or mechanism I could implement that could do this for me?

Any thoughts are much appreciated, I learn so much here. Thanks.

[latreche34]

Optical sensors are the most common, that's what it is used in the VHS format anyway. Beta uses magnetic sensors since the tapes have metallic leaders instead of clear ones, So if cleaning beta tapes is considered you will have to add magnetic sensors as well.

You could get away with using a cheap VCR by just removing the video drum, cut of the tilted posts next to the P guide rollers, Remove the pinch roller, In the space left by the head install your cleaning apparatus, The only problem is that some modern VCRs would go into shutdown if they don't detect a drum rotation, But that can be mitigated by extending the drum ribbon cable and mount it away from the cleaning area and let it spin away.

[ge0dude]

Thank you so much for the reply, this gives me a better understanding. So I would probably control the optical and magnetic sensors with a 555 timer IC. Maybe 2 separate ones if it simplifies it enough, I still haven't looked into circuitry for controlling 2 sensors with one 555 chip but I have some theories.

Now where are these sensors typically positioned? Inside one of the reels? Outside one of the reels? Please excuse my ignorance. Positioning the sensors for the exact stop position seems like a difficult job.

[timtape]

Quote:

Originally Posted by ge0dude

I've seen some really cool examples, but from what I've seen, they manually slow down and stop the motor at the end as to not cause any blowout. Is there some sort of circuit or mechanism I could implement that could do this for me?

I think this slowing down near the end of the wind is normally standard on many better and late model machines. Even tiny mini DV camcorders can have this facility. The speeds of the reels is normally monitored via signals from tacho sensors on the reel tables. It's a great system. No need to reinvent the wheel there.

Just be aware, serious cleaning, especially wet cleaning, rinsing and drying of these tapes without making things worse is no easy matter. Most of us, me included, have never seen up close the cleaning equipment and techniques used by a small number of experts who have been doing this work for a long time. Proceed with great care.

[ge0dude]

Thanks for the reply. I'm not sure I have the talent to isolate specifically which circuit in the VCR does this without accidentally cutting out something important. Nor do I even know if the parts or their equivalents would still be available. There are a lot of variables. I'd probably have an easier time reinventing the wheel here, I know it sounds silly. If someone felt like circling a portion of a VCR circuit that controls the sensor, that would give me a huge leg up.

*EDIT*

I found this schematic online of a Tape Rewinder, but I don't see any sort of detection mechanisms? Looks pretty basic. Maybe its not very fast to begin with.

[Gary34]

I think the VHS is Life people are already operating at close to manufacturing cost. Those are only 115 dollars. I don’t really think an optical sensor is necessary. It would just add manufacturing cost. That isn’t really a set it and forget it thing. All the dust and mold flying around could trip up the optical sensor because with these mold cleaners the reels are out of the cassette. My VHS is Life mold cleaner should be here next week. I am going to clean my moldy tapes outside wish a mask too because it is mold and there are dangers to be aware of.

[ge0dude]

Wow! I was not aware of their products. Thanks so much! Last I read the VHS cleaners were old and I couldn't find any of the suggested models on ebay. This is great! I guess I don't need to do anything then. They even had my same idea for a vent hood to collect the spores and dust. My design has a rated HEPA filter though, I'm sure his filter probably works okay, but I already have a 190CFM in-line fan for soldering so that should do the job.

*EDIT*

Do you happen to have the password to view the product on their page?

[Gary34]

Quote:

My design has a rated HEPA filter though, I'm sure his filter probably works okay,

He’s only charging 115 for the unit then the fan is 40 so yeah he could do more but the price would go up. I have an Allen Breath smart hepa filter in that room and I am still cleaning my tapes outside. I live in the country and I have no neighbors so it doesn’t really bug me to take it outside. My wife will be happier with that.

Here’s a video over it. https://youtu.be/OtDTmiSUwXA It’s a popular cleaner. I also recently bought a knock off and due to my inexperience I thought it was good at first then once I messed with it more I figured out that the reels were loose and it was flimsy. Ow well you live and you learn. The actual V.I.L. Units seem to be more solid. L.S. Wouldn’t recommend any of these cleaners. He would recommend spec bros. L.S. Has a point. The best way to avoid mold is to let someone else do it but it is 100 dollars a tape so there’s always a trade off. I see his point though.

Quote:

My design has a rated HEPA filter though, I'm sure his filter probably works okay

Another thing about the HEPA filter is it would not only require more expensive filters but it would make the cost of the vacuum go up and it would increase shipping costs. The motor for the Vacuum would have to be stronger to work effectively because that kind of filter creates a lot more resistance.

I paid almost 700 for my big air filter back in 2013. The replacement filters are 80 dollars a piece. I needed it then because of who I lived with then. It was a good buy because my twin tripped over it and broke it. When he did I called them because they said it had a lifetime warranty and they replaced the unit even though it was my fault and they said they would again if it broke. I was honest with them too.

When you look at the price of HEPA vacuums they are pretty high. It would multiple the cost of the vacuum by several times. You could always just use your own HEPA vacuum if you have one. The vacuum is an optional add on. A vacuum even a HEPA one won’t get everything. It is a good idea to ware a mask and/or be outside.

[latreche34]

I made a suggestion last year to the guys making that cleaner to install optical sensors for safety purposes, They said they will consider it in the future, Even if you buy one from them I would suggest adding them, The sensors should be connected in series so when any side triggers the sensor the motor stops regardless which direction it's moving. These are widely available and can be positioned 2mm clear from the bottom edge of the tape and the tape should travel in the center of the slot.

[lordsmurf]

Quote:

Originally Posted by ge0dude

I'm thinking about building my own tape cleaner that I could 3D print and hopefully share with the community if it's good enough.

Quote:

Originally Posted by timtape

Just be aware, serious cleaning, especially wet cleaning, rinsing and drying of these tapes without making things worse is no easy matter. Most of us, me included, have never seen up close the cleaning equipment and techniques used by a small number of experts who have been doing this work for a long time. Proceed with great care.

Bolded because true.

I've seen cleaning gear up close. Those $5k RTI were the cheap small "portable" units. Some reminded me of Univac (or a color photo lab processor), large somewhat loud gear, because debris removal was kept securely inside. They don't use these halfwit methods used by the Youtube idiots, who inhale airborne debris (like mold spores), and cover their homes in it.

Quote:

Originally Posted by Gary34

All the dust and mold flying around

That's why the machine is a joke to anybody serious about VHS recovery (and later capturing, restoration). I would never let such a poorly "cleaned" tape anywhere near my capturing gear.

Quote:

I am going to clean my moldy tapes outside wish a mask too because it is mold and there are dangers to be aware of.

I always tell others how I went into anaphylaxis ("anaphylactic shock"), about 7 years ago now, because I was exposed to mold not native to my area (or an area where I'd ever been). I was rushed to the local ER clinic, jabbed in the ass with a needle, and was kept under observation before I could go home.

All those people breathing mold from a VHS tape will suffer some sort of negative issue. Some severe, some not severe. But negative nonetheless. Breathing mold spores is ignorant.

Quote:

Originally Posted by Gary34

L.S. Wouldn’t recommend any of these cleaners. He would recommend spec bros. L.S. Has a point. The best way to avoid mold is to let someone else do it but it is 100 dollars a tape so there’s always a trade off. I see his point though.

If the tape's contents are not worth $100, honestly, it's not worth doing at all.

Quote:

I paid almost 700 for my big air filter back in 2013. The replacement filters are 80 dollars a piece.

We recently gave away a unit, to Habitat For Humanity, because of filter costs. It was a late 1990s (or early 2000s) model, filters were $80 to $100. I looked on eBay, and the unit had no value, only new (NOS) filters.

Quote:

Originally Posted by latreche34

I made a suggestion last year to the guys making that cleaner to install optical sensors for safety purposes, They said they will consider it in the future,

The older I get, the more I do not respect some of these homebrewers/DIY'ers/Kickstarters. They seem to have no care about safety, be it for you, or the object it interacts with. All you get is "it worked for me" and "other people like it", completely missing the point. They have no self awareness that they, and the "other people", don't know as much as they seem to think.

Sometimes people tell me that I need to contact the "inventor" before poo-pooing their "hard work". But from my experience, they don't want to listen anyway, especially if being safer costs more money. They usually want their egos rubbed, and to make the most money possible (even by cutting corners). So it's not just big corporations that are crappy, it's "the little guy" too.

[latreche34]

Forgot to mention that cleaning video tapes is not recommended without a good reason such as mold, flood or other contamination, Cleaning tapes because the cassette looks dusty from the outside or the picture doesn't look good will not improve anything and it may worsen the situation, Creased and damaged tapes should not be cleaned or messed with, if you can't recover it the way it is, splice it.

[Gary34]

Quote:

If the tape's contents are not worth $100, honestly, it's not worth doing at all.

The tape's contents are worth $100 to me.

[ge0dude]

After reading all these comments, I think I might go forward and spend some time this summer trying to develop one of these. The motors are cheap, and the I'll probably use the sensor assembly linked by latreche34. One upgrade I'm considering is an Arduino. It's cheap and could replace a lot of the circuitry. The electronics alone hopefully shouldn't be more than $30 tops.

Please post all ideas, comments, and guidance here in this thread I would sure love that. Most of you have much more experience than I do in this arena.

I have attached a picture of the style of cleaner I would like to build. With options for adding wet towels like the VHS is Life design. I would also like to see if it's feasible to make the Vent hood sliding (up and down) and able to seal around the device completely when in the down position.

[aramkolt]

The IR gate/optocoupler is the right idea, but I wouldn't use just the IR receiver/LED alone unless you are using something like an Arduino that can do something with the raw output from the infrared receiver.

Would be far simpler to use something like this: https://www.amazon.com/dp/B0813L4XQC and then use something like a mosfet or low current draw relay (says it can only drive 15mA) which would cut power to the motor if the light gate becomes open as the clear leader passes through. You would probably need one on each side of the tape, but since you are driving a different motor for FF vs Rew, you'd really just need one of them sensing for each motor on the side where the tape leader would appear based on the direction that the motor is driving.

The VHS is life machine honestly isn't bad for what you get. Only thing I'd probably change is having adjustable positioning for the posts that hold the PEC pads I've used it on some rather moldy U-Matic tapes (though I did have to modify it a bit since full size U-matic hubs are larger than it can fit without running into the vacuum channels, and I added a reverse polarity switch on one of the motors because U-Matic drives both hubs in the same direction for FF/REW, just depends which hub is being driven).

I did think about adding auto stops using the above sensors, but I don't use it nearly enough to justify that and it's not really something that I'd say is meant to be used/left unattended.

This tape played perfectly fine after a few passes with the VHS is life machine. It happens to be a fairly rare Electronic Press Kit for NBC's Gulliver's Travels from 1996 that explains how they made the movie which did have a fair amount of special effects for the time.

IMG_5861.jpg

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[ge0dude]

Thank you so much for the input, that sounds perfect. An Arduino definitely sounds like the right path. Also that's such an awesome piece of history you helped restore, thanks man.

I've been going over motors that fit the criteria for direct drive, I'll probably end up going with this one. According to a few calculations, the 12V 60RPM model should offer good direct drive support, not too fast, not too slow @ max speed. 420 inches per minute. (If anyone feels like checking these calculations, feel free!! I'd hate to break my first test tape with a wildly strong motor haha.)

The optocoupler you linked looks perfect. I'll probably get a 5 pack.

[latreche34]

Avoid built in gearbox motors at all cost, they have enough torque to rip the tape out of the hub or out of a sticky spot, Use straight motors with high belt ratio and a trimmer pot for the lowest speed without excessive torque, Ideally stepper motors are the best but they do need a control board, but I assume it is not a problem for you since you mentioned you can build a circuit for the optical sensors based on the NE555.

[ge0dude]

Huh, very interesting. Thanks so much for that tidbit of information. I wonder if I could use one if i find one just under the torque threshold? They have the encoders that make it really easy to use with the Arduino. The problem with that is the size and wattage go down with less torque, and from there, rise the chances of overheating after prolonged sessions (multiple tapes in a row.)

Lot's to think about, I'll look into my options. Thanks again! Your guidance guys has been *Chefs Kiss*

*edit*

I found this stepper motor, looks like it will do the job with 5:1-10:1ish gear ratio. However that would raise the torque to around 8000g/cm. When I think I need to be aiming for about 200-500g/cm. Would this be an issue with a stepper motor? or a non-issue.

[latreche34]

With advanced motor control you can actually control the torque on stepper motors to the point that you don't even need optical sensors (though, installing end tape sensors is essential for unexpected failures) by just sensing how much load is put on the motor by mean of measuring the back EMF current if I remember correctly, Another way is to install a tape tensioner sensor to sense how much tension is put on the tape by a spring loaded lever arm coupled wit a potentiometer, Generally speaking torque generated by stepper motors is more controllable compared to geared motors.

[ge0dude]

Quote:

Originally Posted by latreche34

With advanced motor control you can actually control the torque on stepper motors to the point that you don't even need optical sensors (though, installing end tape sensors is essential for unexpected failures) by just sensing how much load is put on the motor by mean of measuring the back EMF current if I remember correctly, Another way is to install a tape tensioner sensor to sense how much tension is put on the tape by a spring loaded lever arm coupled wit a potentiometer, Generally speaking torque generated by stepper motors is more controllable compared to geared motors.

Thank you so much for the information. I was able to figure out some of that, but you went into much more detail.

I also decided I'll probably make it battery powered. Some quick maths tell me a 3S lithium-ion battery pack would last all day. It would make it more portable to take outside and make easy work of some tapes.

*Edit*

Does anyone know where I can get smaller spools like the ones in the picture i attached in post #14? That's the one thing I would not want to 3d print since it's in direct contact with the tape.

[latreche34]

Those appear to be V8 cassette reels.