MegaSack DRAW - This year's winner is user - rgwb
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Highly random this one, but I generally encourage my 6yo daughter to do a bit "engineering"/making/tinkering. The other day she announced she had an idea for an invention: an automated toothpaste dispenser. 😆
She's since mentioned it again and done some drawings, so I've offered to help her build "a prototype" as a nice little daddy/daughter project 😀
Obviously in terms of encouraging her, it would be good if it actually worked - or at least came fairly close.
So umm.. advice please?
I'm thinking something like a little LED/LDR light gate on the analog input to an Arduino which then drives a digital output high for a set time when the toothbrush head breaks the "beam".
The output then turns on a transistor that activates a 6 volt peristaltic pump (I've already ordered [url= http://www.ebay.co.uk/itm/Brand-New-Unused-Babyfish-AB12-6V-DC-Peristaltic-Dosing-Pump/302155659582 ]this one from eBay[/url]).
Will that work?
Any alternate designs spring to mind (with a view to simplicity rather than functionality)?
There's a Minions one available - works on a simple push to contact iirc.
[url= https://www.amazon.co.uk/Toothbrush-Automatic-Toothpaste-Dispenser-Minions/dp/B0132TIT6W ](tooth)paste[/url]
There's a Minions one available
Sssssshhhhhhhh!!
This is a COMPLETELY ORIGINAL invention that absolutely NO ONE has ever thought of before and in no way resembles an automated soap dispenser seen in public bathrooms everywhere 😉
(But thanks.. interesting that it apparently uses a vacuum pump)
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Think I want to get some electronics involved though.
You know those taps you get that have a sensor so the water comes out when you put your hands under the tap, well buy one of them and plumb in a giant vat of toothpaste rather than water 🙂
I'd image the consistency of toothpaste may causing you an issue for pumping. Might be better to adapt one of these with a plunger and sensor [img] 
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[url= http://www.tuvie.com/no-more-messy-toothpaste-tubes-with-chube-automated-toothpaste-dispenser/ ]or buy this and take it apart to see how it works[/url] similar to automatic soap dispenser I would think
take a look at the Dettol "no-touch" hand wash dispenser. It uses an optical sensor.
There's a Minions one available - works on a simple push to contact iirc.
not available 😉
Currently unavailable.
We don't know when or if this item will be back in stock.
I'd image the consistency of toothpaste may causing you an issue for pumping.
Yeah that could be an issue. Don't know what those little 6v pumps are capable of, and eBay isn't too helpful there.
I know the 12v ones can deliver ~1.5bar of pressure so could always upgrade if we learn from the prototype that it needs more oomph. (Trying to teach her a bit of engineering methodology).
or buy this and take it apart to see how it works
No need they provide a helpful diagram. Motor turning a threaded rod to push up from the base by the look of it.
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Insane that it requires [i]special[/i] bespoke cartridges when one of those Colgate pump bottles would work pretty well in that design.
What about an Archimedes screw for the feed, with a gearbox to step down the motor. Optical sensor or micro switch with a relay to start the motor?
Make an 'easy clean' version of this -
https://www.ebay.co.uk/itm/122324336621
andyl - Member
There's a Minions one available - works on a simple push to contact iirc.
not available
[url= http://www.ebay.co.uk/itm/Cute-Wall-Mounted-1-Or-2-Eyes-Minions-Toothpaste-Dispenser-and-Toothbrush-Holder-/262854361427?var=&hash=item3d33574153:m:mqpWGZc1iMf1mgSX4uG33cQ ]Available[/url]
There's a Minions one available - works on a simple push to contact iirc.
Got one - good idea but poor product in the simple sense that the force required to push the brush forward is far too high for a 4-6 yr old and the brush easily jumps up off the shelf/pad thing leading to toothpaste everywhere!
Also a pain to fully clean as the vavle thing has to be full of paste to function and inevitibly, being used by kids, it gets everywhere.
I'd think that you might need to consider the nozzle and toothpaste drying out - if it does, you'll need to pump the thick paste even harder.
What about an Archimedes screw for the feed
Interesting idea - but wouldn't that mean we'd have moving parts in the toothpaste? So issues with sealing and hygiene.
Make an 'easy clean' version of this
Looks like a very similar manual lever mechanism to the Minions one.
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I'd like to involve some electronics because... erm... engineering!
If it were me, I'd do something that took the pumps Gary mentions as "cartridges" to load it. That way it's trivial to refill it, and half of the engineering is done for you - you just need a sensor and something mechanical to push the thumb button. Also dodges the bullet of a malfunction dumping half a pint of toothpaste on the floor.
To be honest Cougar, I suspect it will see about as much real world use as the "skateboard for dolls" we designed last week (multiple sheets of cardboard laminated together with PVA with coffee pods for wheels and chopsticks for axles 😆 ). So refills are unlikely to be much of an issue.
Perhaps not, but if you're teaching design it's a good principle to impart perhaps.
Yep true - not sure how I'd press the thumb button if I did that, they need a reasonable amount of force. Maybe little cam or something?
This project needs MOAR LAZERS!!!
I was thinking a couple of lasers pointing in an X that, when the LDRs they point to _both_ break, triggers a motor to squish toothpaste down to the laser spot for a set time.
You could do that with an Arduino. Or, if you use a Pi Zero 3, it could wirelessly notify you when the tube of paste gets low.
Hmmm... maybe I can hook it up to our Alexa and make it voice-activated... 😀
Nah. She's 6. I'd like her to [i]roughly[/i] understand what the code does and right now a bit of ScratchJr is her limit. 🙂
Maybe in Mk 2.