Can I Build a Better Dog Detector for My Motorized Doggie Door?

In summary, the dog-door has a short MTBF and needs to be replaced, but it is a good system for detecting dogs.
  • #1
brianlojeck
3
0
This is not homework, although I am an EE student. If the solution is cool/complex enough, this might become a design project, although it'll most likely end up as something to do over the summer.

some time ago, I purchased a motorized doggie door. The dog wore a high frequency sound generator on it's collar, which triggered a sensor in the door when the dog was within a few feet.

The chassis of the system is good, but the electronics sucked, and the company support was terrible, so I'm looking to gut and rebuild the innards.

The system shouldn't be complicated, a microcontroller monitors a sensor, when the sensor kicks the MCU turns on the motor, when the sensor stops kicking the MCU turns off the motor and the weight of the door closes it (I think reverse-current protection was missing from the original design, which might help explain the short MTBF).

I'm looking for ideas for a dog-detector that can:
1: detect the dog from about 3 feet away
2: work on both sides of the door (multiple antennas is acceptable)
3: not be too ugly that people will ask why there's a big coil of copper on the floor
4: should have a decent off-angle response, since my dog's not that bright, and won't
always come straight at the door
5: detect my dog, but not my cats, or the local wildlife
6: no batteries on my dog, if possible

RFID seems to be the best solution, but most sensors seem to be either very short range (10cm) or very long range (300ft) and very expensive.

One of my classmates suggested a strong magnet on her collar, with an inductive coil on the floor, but this would violate rule 3, and the dog may end up with all kinds of stuff hanging from her collar.

I'm not afraid of soldering, programming, or research, but I could use some bright ideas.

Any suggestions?
 
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  • #2
brianlojeck said:
This is not homework, although I am an EE student. If the solution is cool/complex enough, this might become a design project, although it'll most likely end up as something to do over the summer.

some time ago, I purchased a motorized doggie door. The dog wore a high frequency sound generator on it's collar, which triggered a sensor in the door when the dog was within a few feet.

The chassis of the system is good, but the electronics sucked, and the company support was terrible, so I'm looking to gut and rebuild the innards.

The system shouldn't be complicated, a microcontroller monitors a sensor, when the sensor kicks the MCU turns on the motor, when the sensor stops kicking the MCU turns off the motor and the weight of the door closes it (I think reverse-current protection was missing from the original design, which might help explain the short MTBF).

I'm looking for ideas for a dog-detector that can:
1: detect the dog from about 3 feet away
2: work on both sides of the door (multiple antennas is acceptable)
3: not be too ugly that people will ask why there's a big coil of copper on the floor
4: should have a decent off-angle response, since my dog's not that bright, and won't
always come straight at the door
5: detect my dog, but not my cats, or the local wildlife
6: no batteries on my dog, if possible

RFID seems to be the best solution, but most sensors seem to be either very short range (10cm) or very long range (300ft) and very expensive.

One of my classmates suggested a strong magnet on her collar, with an inductive coil on the floor, but this would violate rule 3, and the dog may end up with all kinds of stuff hanging from her collar.

I'm not afraid of soldering, programming, or research, but I could use some bright ideas.

Any suggestions?

I was thinking RFID as soon as I started reading your post...

CS
 
  • #3
stewartcs said:
I was thinking RFID as soon as I started reading your post...

CS

I still think it's the best idea, but the dog can't be counted on to swipe her tag within 10cm of a reader. Is it feasible to extend the range to 3'?
 
  • #4
How fast does the doggie-door unlock, and how long does it take for the doggie-door to lock after the dog opens it? We have a small scottie, and we have seen two coyoties in our garden recently...
Bob S
 
  • #5
the door slides vertically, pulled by a steel wire connected to a motor. The cable is attached (on teh door side) to the locking mechanism, so whenever it's down, it's locked.

unlocking and opening are pretty quick, although I never timed it.

With the old mechanism, it would be closed within 15 or 20 seconds of the dog leaving the area, but that may change as I'm replacing the motor as well.
 
  • #6
There is an effect where if you have an oscillator and bring a tuned circuit resonant at the same frequency as the oscillator near it, the tuned circuit will absorb some power from the oscillator and the level of signal in the oscillator will dip sharply.

The is the principle of the "grid dip oscillator" used to detect the resonant frequency of tuned circuits.

Used with big coils, it might have enough range to operate at a distance of a foot or so. Maybe more. The tuned circuit could be a capacitor and a coil wound on the dog's collar.

If it did, maybe you could have a board that the dog has to walk on and this turns on a switch which turns on the oscillator. Maybe with a strain gauge it could weigh the dog?How about this?......:smile:

dog bar code.jpg
 
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  • #7
Attachment not working?
 

1. What is a dog detector?

A dog detector is a device or system that is able to detect the presence of dogs in a given area. It can use various technologies such as sound, scent, or visual recognition to identify dogs.

2. How does a dog detector work?

A dog detector works by using sensors or cameras to detect specific features or patterns that are unique to dogs. These features can include barking sounds, body heat, or physical characteristics such as fur color and shape. The detector then analyzes this information and compares it to a database of known dog features to determine if a dog is present.

3. Can a dog detector distinguish between different dog breeds?

Yes, some advanced dog detectors use machine learning algorithms to analyze the data and can differentiate between different dog breeds. This is possible because each breed has distinct physical characteristics that can be identified by the detector.

4. Is a dog detector accurate?

The accuracy of a dog detector depends on various factors such as the technology used, environmental conditions, and the training of the detector. Generally, a well-designed and properly calibrated dog detector can have a high level of accuracy, but it may not be 100% accurate.

5. What are the practical applications of a dog detector?

A dog detector can be used for a variety of purposes, such as detecting stray dogs in public places, identifying missing or lost dogs, or as a security measure to detect and deter intruding dogs. It can also be used for research purposes, such as studying dog behavior and population in a certain area.

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