Picture of RFID pet feeder
If you have two cats and one of them is on a diet but the other needs free food, you can build a feeder with RFID capability that only opens for the cat that needs free access. The free-food cat wears a collar with an RFID tag.  

- An old CD-rom player is used as a sliding door
- Timer-controlled open duration
- Proximity sensor (Sharp GP2D120) prevents door from closing while the cat is eating
- Sensors detect whether the door is fully opened/closed. 
- Automatic/manual mode switch (on manual it opens with a pushbutton)
- Arduino controlled

On the downside:
- Mine was made out of cardboard so it is easily broken into by smart/strong animals. One could use a stronger material and add a servo that slides a bar into the door to lock it into place. 
- It doesn't hold a lot of food. 

The first version (shown in the video) used an ID-20 (ID Innovations), which worked, but the range was limited. The cat's tag sometimes hangs on the side, so it did not always activate the reader even when he was in the exact same place every time. Not that big a deal because the cat usually just tried from different angles, but my latest version (shown in the photograph) uses a SEEED studio RDM630 RF-reader with a self-made circular antenna. This antenna is large enough that the cat can poke his head through, which works 100% of the time. The antenna is described in step 7.

Little Cat Toos demonstrates cat feeder from champenoise on Vimeo.
The video shows the first version with the ID-20 as the reader.

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helpme_19 days ago

nice project. I want to make a same one but could only locate 16AWG wire. At 6" diameter, how many turns should I do?

Could someobe who might be interested in building a custom animal feeder for me please contact me? I need a feeder that dispenses wet food, in my case bits of meat, to falcons when they enter a feeding box. Additionally i need it to weigh the birds and record the birds weight and amount of food consumed. The birds would be fitted with rfid leg bands. P
DiwaP6 months ago

Thanks :)

kilofeenix1 year ago

anyway to make this work with the rfid chip in my cats neck? no way in hell she's gonna wear a collar. otherwise i need to make it close when my dogs gets too close and stay open when hes not around. its for a litter box door to prevent my dog was munching down some almond roccas

I have the same problem. Build it so that the bowl is constantly open and then closes when the dog gets close enough (the dog wears the tag). I imagine that a CD drive would not be fast enough,so you could use a servo and a flap.
See post above.

David97 David977 months ago

Like this... it would be easy to add a flap to lock them out

David977 months ago

Great instructable. I would have designed it so that the cat that does not need food where's the collar. That way the cat does not need to be trained to use it. It simply closes and locks when the other cat tries to access it. Also makes it easier to fill.
I want to build one because one of my dogs can't be trusted around the bowl. My cat does not like wearing a collar, and manages to get them off and loose them. So for me it would be better to lock the dog out instead. However I would need a faster way of shutting it. Maby a servo and flap.

make sure the ir receiver is working mine went faulty and caused it to stay open lil bang on it and it would close

LesB1 year ago

I have had my feeder working for a number of months now. It works well, except that every once in a while it will hang up and stay open. Has anyone experienced this problem?

hsjade13 years ago
I want to build this but new to RF. Was wondering do u have an image of all parts used

Wondering the same thing here

lamudd011 year ago
I am planning to start this project soon and was wondering if anyone had already played around with incorporating some regulation of access in regards to the amount of food? i.e. using a load cell or other mechanism to control the amount of food that can be accessed over a certain time period? I'm hoping by doing this 1) it will prevent the cat from gorging itself all in one sitting and 2) provide positive reinforcement in adjusting to the new bowl (there will be food when the door is opened, instead of it being emptied first thing in the morning and empty until dinner time). I was thinking of including a setup similar to but just wanted to check if anyone else had any experience/pointers/better setups of doing this beforehand.

Wireless Whiskers has a commercial version with lots of features including being able to set pets on different diets and access control to shut out certain animals. Check it out it looks pretty cool
LesB1 year ago
BTW, anyone planning to build this, I found that the Sharp GP2D120 proximity sensor worked very well. Has an adjustable range.
LesB1 year ago
I completed my catfeeder a few months ago and it is working great. Here's a Vimeo of the cats and feeder in action (poor quality, sorry)

-The first cat comes by and the feeder hatch opens for him and he partakes.

-He leaves and the second cat comes by and sniffs around the feeder.  When she sticks her head in you can see the proximity light go on, but the hatch doesn't open because she doesn't have the requisite RFID tag. 

-After a while the first cat comes by and gently shuttles the second cat away from "his" feeder.

It works great!
With the tags on the cats collar make sure that they aren't wearing metal name tags as well because that interfered with mine and drove me nuts for ages trying to figure out why it would only work sometimes .

This is my version of landmanr"s project

Everything is basically the same except mines made from perspex and incorporates a gravity feed system

Big thanks to landmanr for this instuctable it helped my situation massively.
split551 year ago
I need to build 2 of these. As I have 2 cats that cannot eat the same food. Do I need 2 Arduino's adn 2 motorshields? In other words, can I build one of these with 2 doors, with each rfid opening only 1 door?
Antenna resonance details are pretty important, more so than, say, the thickness of the wire used for the coil. Please see (RFID in Instructables) and you will notice a RFID detector here with an LED that uses both a coil AND a capacitor that matches 125 kHz. The LED on this detector lights at the farthest distance from the RFID reader when the coil and capacitor resonate at the frequency of 125 kHz. Roughly speaking, my handwound coil of about 300 uH with about .005 uF of capacitors in parallel with the coil resulted in the best lighting of the LED at a distance of about 4+ inches and mostly meets the requirements of the formula; freq = 1000 divided by (2 times pi times the square root of L times C) where freq in in kHz, C is in uF and L is in uH. I believe that using a capacitor in parallel with the antenna coil is pretty common practice. The wound coil is "fine tuned" by capacitors hooked up in parallel with the coil...
LesB2 years ago
I have just finished building my own version of this project. First of all, the following observations:
-Having built this I can appreciate the extensive work landmanr did in developing the feeder.
-I used this project to break myself into learning about and using the Arduino. Having gone through this, I do not recommend this as a project this complex for a first-time Arduino project. Better to start with something simpler to break yourself in. Or, be prepared to take the time with this project to learn the ins and outs of the Arduino.
-Landmar was very helpful in answering a bunch of questions for me. If you decide on this project and you run into obstacles feel free to ask me for help as well as landmar.
-The RDM6300 RFID reader has been discontinued. I am using the ID-20.
-Other posts in this forum refer to a cat door and a cat feeder in the design stage that work with the cat's implanted RFID chip. When I can find out just how that is done, I will probably upgrade my feeder to do that.

The following link goes to pictures of my feeder. Being the nerd that I am I like stuff with flashing LED's, so incorporated several LEDs that glow to indicate various functions.

If you saw the pictures, I'm sure it isn't lost on you that my unit is boxy and mechanical looking. This is the kind of thing my mother would not let me keep in the house when I was a teenager. This, as opposed to landmar's unit, which is smaller and decorated with designs.

I am presently in the cat-training stage. I will post a video of the feeder in action when it is in full-swing.

Regarding the indicator lights: My background is in electronics, and I have just started learning about writing sketches for the Arduino family. Thererfore I used electronic means to implement the LEDs instead of coding, which would have been a simpler, more elegant solution. But it is what it is. With that expalined, the next link takes you to a shot of the schematic of my unit.

The picture is not large enough to show much detail. I can send a full-size copy if anyone would like. Send me a message from this site.

Like I said, at our house we are in the training stage. The cat without the RFID tag succeeded in breaking into the unit, so I had to reinforce it. The cat with the tag acts very suspicious of the thing. I'm not sure if it's me training the cats or them training me, I'm confident that we soon will be living in harmony with this machine.
jaxworld2 years ago
Great idea, but I have twin Egyptian cats (named Coco and Chanel by my fashionista G'f), and they would rip that apart in about 3 seconds......had to put child locks on the fridge door coz they'd open it.
They get into cupboards above the kitchen surface and we've never caught how they do that...............BUT.....the reason for the child locks was they could get IN to the fridge, but not get out.
So after mild frostbite twice we had to come up with something that they couldn't reach.
But they can destroy anything with food in it that isn't made of steel!!! One nearly drowned in our 5ft high hexagonal fish tank, got in, couldn't get out. Now has four velcro strips coz two they could work.....
We live with Ninja cats!
Had a timed feeder......had to upgrade the motor and lock and put a couple of tiles on it coz they worked it out in 48hrs!
Don't have children,but have trigger locks on my guns for the same reasons!!!
Anyone who could come up with an ARMOURED feeder PLEASE inform!!!
I wouldn't trust them with a frag grenade!!! Never seen two team cats like it, I'm ex-mil and if they were human would love them as part of a 4 man team!!!
Solutions welcome!
Armoured, timed, cat feeder wanted!!! One week good as could put blue freezer packs beneath!
It's certainly doable, though likely to be moderately expensive if it's to be truly durable and reliable (and you want reliable, an armored lid could decapitate an animal--or leave them trapped!)

Did you put child-locks on the cupboards to?

I'd keep them from grenades too! They would have the in pulled in a matter of hours at most.

Drop me a line at my handle here -0 g mail & we can discuss it.
v4l2 years ago
Hi, that's a really cool project, totally useful for my cats :)
Would it be feasible to replace the Arduino Duemilanove with an Arduino Uno?
landmanr (author)  v4l2 years ago
Yes, it's most likely no big deal
tlshea3 years ago
I realize this is the site and the idea is to do it myself, but I am a desperate woman in need of something like this now (before my cats make me crazier). Is there anything commercial that performs this?
I do salute your inventiveness and everyone's successful modifications.
Thank you for any insight.
Caseyjmc tlshea2 years ago
Yes! MeowSpace
gcresse tlshea3 years ago
I just ordered this ID Bowl from and it seems to be exactly what a person needs to keep one cat from eating the other cat's food. It hasn't arrived yet, but hopefully it works as well as on the video.
landmanr (author)  gcresse3 years ago
That's pretty neat! The only downside I see from that design is that it utilizes infrared, so the tag will have a little battery which I could run out of power.
Yeah, I also ordered an extra battery. We'll see how happy I am with it after I've used it for a while.
Hi gcresse. Did you have success with the id bowl? I'm looking at buying three sets and I haven't found any other reviews.
We have an ID bowl and have been disappointed so far. The bowl is fairly noisy when it opens and closes, so our regular cats are a bit scared of it (while the fat one just comes running whenever he hears it). The IR tags seem to be prone to failing when they get wet (though they seem to resume working when they dry out), which means when the cat drinks out of a bowl it can kill the tags. The triggering is somewhat inconsistent, depending on what angle the cat approaches at. And, it tried to close on one cat's head, I think because they were eating from an angle. The first one we got had a tendency to "bounce" a few times when manually switched off (it opens when switched off). The replacement was a lot noisier and kind of stuck mid-opening, releasing with a "clack" (again, cats didn't appreciate). Waiting on replacement #2 now. This is the "first infrared pet feeder" - I'm thinking maybe when the design evolves to the third or fourth (and build quality improves) we'll get the one that actually works. And I think RFID is probably a better way to go.
Thanks for the feedback Bob! I'll keep searching for a solution to the #1 dog on a diet, #2 blind dog eating cats food, and poor cat searching for left-overs since the dogs eat everything . ;)
landmanr (author)  tlshea3 years ago
Hmm, not that I know. There is a host of electronic pet doors available, so if you have a larger space to put the food in you could use such a door to control access. Just an idea.
Caseyjmc2 years ago
We created another solution using polycarbonate plastic and a locking pet door. Several of our friends asked us to build one for them, and then their friends wanted one too. Little by little, we improved this, and added some bells and whistles. Now, we sell it online. It's called MeowSpace®
LesB3 years ago
I've having a problem reading the schematic for the Auto/Manual switch. It's posted as a thumbnail and I can't read it. Could you either describe the connections or send me a full size picture? I'd appreciate it; Kitten Kaboodle would appreciate it:
landmanr (author)  LesB3 years ago
I have attached an image to this reply. See if that works..
LesB landmanr3 years ago
Works! Thanks, I appreciate your help.
For a single cat, wouldn't a magnet/switch combo be a much more elegant and inexpensive solution, eliminating the arduino circuit? (all other cats/animals in the home simply wouldn't have the magnet, so voila, no access!)
landmanr (author)  solaralternatives3 years ago
Great idea, although magnets don't typically have a lot of range. One could train the cat to do it exactly right, but the magnet would not always be hanging straight down so perhaps with several magnets around the collar.
I was thinking neodynium.. and a coil detector
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