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This is a cat door/flap that can only be opened by the animal that wears the appropriate RFID tag. Arduino controls the process. It features a custom made antenna large enough to function as a gate, which makes it easy for the animal to activate and quite reliable. Some methods and techniques are borrowed from my previous project, the RFID cat feeder. Whereas the feeder controls access to a food bowl, the door controls access to an entire room. The latest code can also distinguish between tags to allow the system to behave differently for different individuals.
How it works:
1. In the beginning the door is locked, cat is outside
2. Cat walks up to the gate, RF tag gets read within about 4 inches
3. Door unlocks and a light comes on.
4. Timer ensures that door stays unlocked long enough to give cat a chance to respond
5. Cat pushes open the flap and enters
6. Flap falls back, activates Hall effect sensor, and the door locks
7. Going from the inside out, an infrared proximity sensor detects the presence of an animal if within about 10 inches and unlocks the door.
Most animals will quickly learn to push the flap in response to the click (lock) and the light. Make sure that the edges of the door and the doorway are padded with soft material for when the tail gets caught! A few painful experiences may be enough to make the cat never want to go in there again.
The electronics are shown without enclosure, but it is advised to put an enclosure around the electronic parts once you're done. It is not further discussed in this Instructable however.
How it works:
1. In the beginning the door is locked, cat is outside
2. Cat walks up to the gate, RF tag gets read within about 4 inches
3. Door unlocks and a light comes on.
4. Timer ensures that door stays unlocked long enough to give cat a chance to respond
5. Cat pushes open the flap and enters
6. Flap falls back, activates Hall effect sensor, and the door locks
7. Going from the inside out, an infrared proximity sensor detects the presence of an animal if within about 10 inches and unlocks the door.
Most animals will quickly learn to push the flap in response to the click (lock) and the light. Make sure that the edges of the door and the doorway are padded with soft material for when the tail gets caught! A few painful experiences may be enough to make the cat never want to go in there again.
The electronics are shown without enclosure, but it is advised to put an enclosure around the electronic parts once you're done. It is not further discussed in this Instructable however.
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Signing UpStep 1Parts list
- Arduino Duemilanove
- 5V RF reader module (Seeed Studio 125Khz UART or equivalent. Most readers come with a small antenna. To use the custom made antenna discussed here, you need a reader that allows connecting an external antenna)
- RF tag (I used these 35mm disc shaped ones)
- About 86 feet of 24 gauge magnet wire (longer than the piece shown in the photograph)
- Sharp GP2D12 infrared proximity sensor
- Two 12V electronic cabinet locks (Nordson electronic). Solenoids, basically.
- One 12V DC power supply
- Two TIP120 Darlington transistors
- One Hall-effect sensor
- One or more magnets to activate Hall-effect sensor over a range of about 2cm
- One 100 Ohm resistor
- Four 2 KOhm resistors
- Two pushbuttons
- One LED
- One hinge (one that moves easily but without much lateral movement, for precision)
- One 6" x 9" piece of 1/8" thick Plexiglas and perhaps another piece of about 6" x 3" to mount the locks
- Hookup wire, including about 27" extra thin (26 AWG or thinner)
- Nuts, bolts and serrated washers
- Rubber isolation strip or other soft material for padding the edges of the door and door post
The system comprises several 'modules' (solenoids, RF reader, and so on). One of the pictures here shows the basic plan with the modules connected to the Arduino (the electronics). In the next steps the mechanical parts and each of the modules will be discussed in detail.
- 5V RF reader module (Seeed Studio 125Khz UART or equivalent. Most readers come with a small antenna. To use the custom made antenna discussed here, you need a reader that allows connecting an external antenna)
- RF tag (I used these 35mm disc shaped ones)
- About 86 feet of 24 gauge magnet wire (longer than the piece shown in the photograph)
- Sharp GP2D12 infrared proximity sensor
- Two 12V electronic cabinet locks (Nordson electronic). Solenoids, basically.
- One 12V DC power supply
- Two TIP120 Darlington transistors
- One Hall-effect sensor
- One or more magnets to activate Hall-effect sensor over a range of about 2cm
- One 100 Ohm resistor
- Four 2 KOhm resistors
- Two pushbuttons
- One LED
- One hinge (one that moves easily but without much lateral movement, for precision)
- One 6" x 9" piece of 1/8" thick Plexiglas and perhaps another piece of about 6" x 3" to mount the locks
- Hookup wire, including about 27" extra thin (26 AWG or thinner)
- Nuts, bolts and serrated washers
- Rubber isolation strip or other soft material for padding the edges of the door and door post
The system comprises several 'modules' (solenoids, RF reader, and so on). One of the pictures here shows the basic plan with the modules connected to the Arduino (the electronics). In the next steps the mechanical parts and each of the modules will be discussed in detail.
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I tried to download the reader programme you shared but when I want to open it, I have a lot of errors, like java not found, it's a red text under the place where you can write your arduino code .
Sorry for the grammatical mistakes, I'm French ;-)
Thanks to answer us, it's kind of you.
10x10 inches was the biggest I could get with this RF reader. I varied the number of turns as a way to 'tune' it, trying it out with a tag each time.
NOTE: There may be some changes and improvements coming.
However this circuit does work and you can build it as shown.
The PCB Shown below is Available from me, or make it yourself.
It Measures 2.75" by 1.1"
This circuit uses one tuned coil for on the door and just a single wire loop
on the animals collar.
When the two coils come close together, it produces a signal that can cause
a an LED to light and also trips a solenoid to unlock the door so it can open.
Since all these doors are somewhat different, I leave The Solenoid and Mechanical
Parts of this design for you to figure out.
The Main Advantage of this unit is it does Not Require any Battery on the
animal, as is the case with most store bought devices for this purpose.
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The Single turn coil can be joined with plugs so it can be removed easly.
But if the plug comes apart or has a poor connection, the door won't open.
So Better yet, make it Just Barely big enough to slip over the animals head,
and Solder it to make a solid loop, than tape it to the animals collar.
And the Larger the diameter of this coil, the Greater the Sensivity will be.
Also Important, the Cat or Dog door and the surroundings "Can't contain any
large pieces of metal".
(This circuit is also a Metal Detector and This detector see's the Single Loop
of wire as a solid piece of metal.)
Additionally, the coil on the door needs to be mounted in such a way that the coil
on the animal can actually get almost inside the coil on the door.
Possibly a Round or Rectangular Extension, outward from the door will be
needed to accomplish this.
Either way, the coil on the door will probably need to be mounted a few
inches from the door.
Ideally the coil on the door will have an inductance of about 150 uH.
My Inductance calculator can determine this for a Round Coil.
One of our cat chews on, and destroys the little jingle bell on his collar aprox every 2 months, which means careful placement of the tag is required to keep it out of his bite radius.
http://www.amazon.com/Cat-Mate-Elite-Selective-Door/dp/B001D6RSMS/ref=cm_cr_pr_product_top
http://www.amazon.com/Electronic--Cat-Door--Sensor-Collar/dp/B000UB5A4U/ref=sr_1_1?s=home-garden&ie=UTF8&qid=1295929645&sr=1-1