[HN Gopher] 3D printable cat feeder  (2020)
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       3D printable cat feeder  (2020)
        
       Author : jsiepkes
       Score  : 84 points
       Date   : 2021-08-23 07:19 UTC (1 days ago)
        
 (HTM) web link (piotr.westfalewicz.com)
 (TXT) w3m dump (piotr.westfalewicz.com)
        
       | mrbbb wrote:
       | I was about to do this with a watering station. After reading it
       | took them 1.5 years tho, I'll probably reconsider.
        
         | spookthesunset wrote:
         | One thing I've learned over the years is it usually isn't worth
         | trying to custom build something you can get on Amazon for $50.
         | The adult in me knows this but damn is the kid in me
         | dissapointed.
        
       | exabrial wrote:
       | Side note, what the blog software he's using? Looks really nice
        
         | Youden wrote:
         | If you view the page source: "Hugo 0.55.6 with theme
         | Tranquilpeak 0.4.3-SNAPSHOT"
        
         | SevenSigs wrote:
         | Hugo 0.55.6 with theme Tranquilpeak 0.4.3-SNAPSHOT
        
       | daemonk wrote:
       | This is awesome. And the data can be really valuable. I think
       | feeding and litter box habits are some of the best indicators for
       | a cat's health.
        
       | kevinbowman wrote:
       | I really like that this weighs the cat; having regular, non-
       | intrusive cat health metrics is particularly useful. Weight
       | change can be a sign of a variety of other issues, but also
       | probably a bunch of non-issues, so _only_ weighing a cat on an
       | annual visit to the vet is less useful but it's quite a pain to
       | manually weigh the cat each day to see trends. Even if only to
       | calibrate the amount of food to dose over time, it's a useful
       | feature.
       | 
       | Nice project!
        
         | whateveracct wrote:
         | I just have a baby scale I plop my guys on occasionally. And
         | then I record their weight in an iOS note.
         | 
         | Weighing your cat and paying attention to their digestion
         | (recording vomiting frequency, inspecting stools) really goes a
         | long way towards keeping a cat healthy.
        
         | codazoda wrote:
         | I own a Wyze scale and I noticed my cat standing on it. So, I
         | created an account for her. She steps on it often enough that
         | the wyze app gives me weight charts for her. I bet it would
         | give me readings multiple times a day if I just set it in front
         | of her food dish.
        
       | ta988 wrote:
       | This is a bad idea. 3d printed objects unless filled with food-
       | grade resins are not food safe as they cannot be cleaned (ridges
       | of the layers) and tend to release a lot of not well
       | characterized compounds.
        
         | spookthesunset wrote:
         | The clear food bin in the video looked like a "normal" bit of
         | plastic--almost like a large licorice container. The only other
         | part that is in long contact with the food is the actual bowl
         | where kitty eats from. Design it so it fits a dishwasher safe
         | bowl of some kind and you are good to go. The "guts" where the
         | food falls through has minimal contact and for a dog or cat I
         | wouldn't loose too much sleep over. For humans I might do
         | something more...
         | 
         | That being said... cleaning the "guts" might be a challenge and
         | I can see it getting kinda skanky over time. Either reprint the
         | parts periodically or find a way to clean them.
        
         | Youden wrote:
         | > This is a bad idea.
         | 
         | Why did you have to add this? The rest of your post raises a
         | valid point and then suggests a way to address it.
         | 
         | Is one small addressable flaw enough to render the rest of the
         | project "a bad idea"?
        
           | TeMPOraL wrote:
           | I wouldn't call creating a health hazard for your cat a
           | "small" flaw.
        
             | spookthesunset wrote:
             | I'm no feline toxicologist but cats only live like 12
             | years. I don't think that is long enough for this kind of
             | thing to really have any effect.
             | 
             | Plus given it is dry food, I wouldn't loose too much sleep.
             | I see animal food and water stored in all kinds of dirty,
             | janky contraptions.
        
             | JoeAltmaier wrote:
             | ...unless you fix it, as described. Then it's not a flaw at
             | all.
             | 
             | The rules here say to read each post with the most positive
             | interpretation. Snark is never welcome, and that could have
             | been said differently e.g. "A great idea! Be sure to use
             | food-grade resin!"
        
               | elif wrote:
               | Please stay on topic you are not a moderator
        
               | JoeAltmaier wrote:
               | Oh sorry, are you? I did not know.
        
               | TeMPOraL wrote:
               | Fair enough. Your alternative phrasing sounds much
               | better!
               | 
               | Thanks for the reminder. I suppose I'm somewhat
               | desensitized to snark these days; that's not a
               | development I like.
        
               | JoeAltmaier wrote:
               | Me too! I find myself deleting posts as often as I write
               | them. In that case I go back and read some of what you
               | have written, to remind me how to be calm and
               | considerate.
        
               | TeMPOraL wrote:
               | Me? Calm and considerate? Do you even read my comments?!
               | 
               | Seriously though, thanks. While I strive to be what you
               | just said, I also delete roughly half of my comments
               | before even submitting them (and every now and then, few
               | minutes after), and I'm not really happy about the rest.
               | I'm pretty grumpy these days, I'm starting to hate the
               | technology business more with every passing moment. Is
               | this too much HN, or just youthful naivete expiring?
               | 
               | (Few years ago I learned that I won the third place in a
               | ranking of HN's top posters of profanities - according to
               | some dataset someone is keeping on Kaggle. This dubious
               | honour made me tone down my language quite a bit.)
        
               | JoeAltmaier wrote:
               | I've never won third place in any contest!
               | Congratulations! I'm impressed.
        
               | TeMPOraL wrote:
               | Why, thank you!
               | 
               | In the spirit of keeping the positivity train rolling,
               | you're the third person (after my wife and daughter) to
               | make me smile today, so consider yourself the 3rd place
               | winner of this impromptu contest!
        
         | devmor wrote:
         | Came here to comment the same thing. Please don't put food on
         | 3D printed surfaces, for humans or animals.
        
         | inportb wrote:
         | For a print this size, I wouldn't use resin. I imagine he used
         | FDM. You might want to consider printing food-related items in
         | PLA. The ridges do present a problem, but could be mitigated by
         | sanding or coating (again, food-grade).
        
           | willis936 wrote:
           | PLA isn't considered food grade but a marginally more
           | expensive and difficult to work with, PETG, is food grade.
        
             | Steltek wrote:
             | I don't think switching to PETG is an automatic win? You
             | still have a rough, porous surface that can trap bacteria.
             | 
             | I stay away from food-related prints but I thought the best
             | method was to print in whatever reasonable material you
             | want and then coat it in something food grade, like resin.
             | Then you get the material and print properties of PLA,
             | PETG, whatever but food safe.
        
               | devmor wrote:
               | Or use the print to make a mold for casting food grade
               | resin.
        
           | GravitasFailure wrote:
           | I believe they were suggesting using a food safe epoxy resin
           | coating, not using a resin printer to make the part.
           | Honestly, since it's dry food the usual food safety risks are
           | fairly limited.
        
       | OJFord wrote:
       | > Please note: the views I express are mine alone and they do not
       | necessarily reflect the views of Amazon.com.
       | 
       | Why would they? Because of a little diagram of using AWS IoT,
       | Lambda, and S3? Weird disclaimer.
       | 
       | Cool project though - I particularly like graphing the cat's
       | weight too, seems like it doesn't really overeat just because
       | it's available. I've never had cats, but I think dogs would
       | basically just wolf it all down every time you filled it up.
       | Though that could be an interesting experiment, assuming that
       | _was_ the starting point, teaching them that the food is
       | plentiful, and they can just use the feeder when hungry.
        
         | papercrane wrote:
         | > Why would they? Because of a little diagram of using AWS IoT,
         | Lambda, and S3? Weird disclaimer.
         | 
         | I'm guessing he added that because he's Amazon employee.
        
         | laumars wrote:
         | Because he works for Amazon.
         | 
         | That might even be a standard footer across all of his blogs.
        
           | OJFord wrote:
           | Oh ok. It doesn't really make sense without disclosing that
           | though.
        
             | laumars wrote:
             | He does. That's how I know he works at AWS.
        
       | nallic wrote:
       | Will there be an automated cat litterbox integration soon ? ;)
       | 
       | Really awesome build!
        
         | zihotki wrote:
         | Actually you can teach your cat to use standard toilet and add
         | there some sort of automatic flush.
        
       | willis936 wrote:
       | Here is my (much lower tech) 3DP solution to feeding my cat. He
       | is insane and will eat as much as he can. If he was free fed he
       | would die. If he eats from a bowl his food is gone in 30 seconds
       | and he gets agitated.
       | 
       | https://www.thingiverse.com/thing:4335532
        
         | panzerklein wrote:
         | This looks nice. My cat is the same and I use plastic bottle
         | with a couple of holes.
        
       | bborud wrote:
       | Yeah, I'm going to need something a lot more robust than that to
       | keep my cats out of the feeder. They rip the lids off of the
       | metal cans I use to store cat foot. :-)
        
       | bactisme wrote:
       | What a gentle cat ... I know cats that would have immediately
       | dismantled the things for research purposes.
        
         | UncleOxidant wrote:
         | Cats are scientists.
        
       | elif wrote:
       | What a shame. There are a dozen automatic dry kibble feeders you
       | can buy for $50. The dashboard/stats are kinda all trivia. This
       | is okay for short trips or fortunately young/healthy cats.
       | 
       | But what will really push the cat robot meta forward is a feeder
       | capable of refrigerated wet food dispensing.
        
         | zarmin wrote:
         | What a shame?
        
         | HyprMusic wrote:
         | Cat mate's rotating feeder works well for this. You dish out 5
         | portions, pop some ice packs underneath it and it will rotate
         | at the given time to reveal the food. Not perfect but it lasts
         | ok overnight, especially if you put in the next morning's food
         | frozen.
         | 
         | I did start building an arduino powered copy of it using a
         | peltier plate and some fly prevention mechanisms. The prototype
         | worked well but since I'm at home 24/7 these days the project
         | fell off my priority list. Maybe this will inspire me to finish
         | it.
        
         | dangerbird2 wrote:
         | Yes! Wet cat food is so unpleasant to deal with, despite being
         | arguably much healthier than kibble. IIRC, since cats prefer to
         | get their fluids from food rather than drinking water from a
         | bowl, wet food goes a long way in preventing dehydration and
         | associated kidney issues.
         | 
         | I guess the reason we've never seen a wet food dispenser is
         | that the only thing worse than cleaning gross wet food residue
         | from a bowl is cleaning it from an overengineered electric
         | dispenser.
        
           | at_a_remove wrote:
           | I think a wet food dispenser would be fantastic, but you are
           | right in that there are quite a lot of hurdles to it --
           | spoilage, the often unpleasant smell of wet cat food, the
           | tendency for it to gum up the works as opposed to the more
           | tractable to automation kibble, which merrily rolls along.
           | 
           | My gut feeling here says that any solution in this area is
           | going to involve some kind of can engineering, maybe as far
           | back in the chain as having specially designed wet food
           | dispenser _cans_.
           | 
           | Refrigeration, too, would come into play unless you were
           | working on a one-redesigned-can, one-serving paradigm.
           | Perhaps a Peltier cooler with the waste heat going to warm
           | some kind of cat friendly pad, as well as the food once
           | served (given that they are carnivores, I am betting that
           | cats would prefer wet food the approximate temperature of
           | mouse guts).
           | 
           | And do not get me started on the struggles of multiple cats,
           | where one or more cats is on a special diet.
           | 
           | I think wet food dispensing could honestly be very healthy
           | for cats (or dogs) but we just haven't spent much time
           | engineering for it.
        
           | burnished wrote:
           | I think it is a little stronger than preference, my
           | understanding is that cats are supposed to get the majority
           | of their water intake from their food AND that their tongue
           | is not very efficient at drinking water, unlike a dogs which
           | is very efficient.
           | 
           | This [1] video does not state my conclusion, but it does (in
           | less than two minutes) show slow motion footage of dogs and
           | cats drinking. You can see that the dog curls its tongue and
           | visibly gets much more liquid up compared to the cat.
           | 
           | [1]
           | https://www.youtube.com/watch?v=295bNJiTA20&ab_channel=Slate
        
         | spookthesunset wrote:
         | Maybe they need a giant over engineered press that requires
         | internet connectivity to scan and validate each bag of wet cat
         | food. We could make it a subscription and each week customers
         | would get fresh bags of healthy, organic pre-masticated cat
         | food.
         | 
         | It will be like Netflix meets Nesspresso but for cat food!! We
         | could call it juicero, er..."catero"!
         | 
         | But seriously. I'd love a good solution for automatic wet cat
         | food.
        
         | goblue wrote:
         | https://pawbot.com/ has been in various stages of product
         | development for years now, the last I heard of which was an
         | attempt to reduce scope & cost
        
       | kuu wrote:
       | This is awesome!
       | 
       | With all that data you could do some ML model to make sure your
       | cat is on proper weight (or study the patterns just for fun even,
       | if you later don't apply it), like delivering more or less food
       | or at appropriate intervals.
        
       | Noxmiles wrote:
       | I like a good overengineering! :3 Very nice to watch / read.
       | 
       | Also: see his blog for posts about the PCB design and STLs etc:
       | https://piotr.westfalewicz.com/blog/
        
       | numlock86 wrote:
       | I always had the impression that feeding your car (or any pet in
       | general) was important social interaction for the animal.
       | Automated feeding is at least cool for when you are not around
       | much or for a few days only I guess.
        
         | inglor_cz wrote:
         | Maybe the cat is 3D printed too...
         | 
         | Just joking, but actually, 3D printing works with living cells,
         | though not yet up to the level of printing an entire animal :)
         | 
         | https://en.wikipedia.org/wiki/3D_bioprinting
        
         | lexicality wrote:
         | From what I understand for dogs it's very important for you to
         | feed them, but for cats it's more important that food is made
         | available to it regularly and consistently than from you
         | specifically.
         | 
         | If a cat is hungry and knows you provide food, it will keep
         | trying to figure out ways to make you give it the food which
         | can lead to very strange and negative behaviours.
         | 
         | However if a cat learns that food will show up in a mysterious
         | box at precise times, it will just wait until that time which
         | will make it happier as it understands what it has to do to eat
         | (wait) and you happier because it won't be scratching at you
         | and yowling
        
           | kevincox wrote:
           | Yup. I had a very "food motivated" cat and our lives was made
           | much more pleasant by setting a "food alarm". That way she
           | wouldn't bother me until the alarm goes off.
           | 
           | My current cats are free-fed but they get quite annoying if
           | their bowl runs low. (they know how to get your attention)
        
         | the_third_wave wrote:
         | Feeding the cat is an important social interaction as well as a
         | sure-fire way to get the critter to show up when you want it to
         | (assuming the cat is even allowed to go outside of course, this
         | is not a given). In that respect a cat feeder is a net
         | negative...
         | 
         | That said, this is a well-executed project which integrates a
         | number of skills - theoretical, mechanical, logical - to
         | produce something useful.
        
         | at_a_remove wrote:
         | Hand-feeding _is_ important for kittens and feral cats, but
         | once they are grown and domesticated it is less so. They do
         | like you to be involved, but there 's quite a bit of annoying
         | behavior once the cat learns that you feed them the first thing
         | in the morning. I guess if I wake you up early ...
        
           | wlesieutre wrote:
           | I've pushed my cats' breakfast time back a few hours after I
           | wake up so they can't directly associate "human is awake now"
           | with "it's time for food!"
           | 
           | They've since stopped waking me up before my alarm goes off,
           | and I can even sleep in a bit on weekends.
           | 
           | This was easier to do when my office was full remote for
           | COVID, being in New England we're starting to reopen now.
        
         | UncleOxidant wrote:
         | I've got an automated feeder that drops food at 3AM because I
         | got tired of getting up at 3AM to feed them - they would get
         | pretty insistent. I hand feed them the rest of the day unless
         | I'm going to be out and then I turn on the other feed times on
         | the feeder.
        
         | JoeAltmaier wrote:
         | I don't think my outdoor cat give a flying flip whether I'm
         | around when it's eating the mouse it caught.
        
       | mopierotti wrote:
       | In a similar vein, having fostered 30+ cats, I've found that
       | using a "food tree puzzle" is especially useful. It's a good way
       | to let them have snack and entertain themselves when they feel
       | like it, without letting them potentially binge eat. (This is in
       | addition to wet food as primary meals)
        
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