How to detect objects in range of 30 cm (180/360 angle)

kolqa_
Posts: 2
Joined: Tue Dec 15, 2020 2:00 pm

How to detect objects in range of 30 cm (180/360 angle)

Postby kolqa_ » Tue Jan 12, 2021 7:44 pm

Hello,

I can't find suitable solution maybe someone faced with same problem. The main goal is to detect my cat near by water bowl and turn on/off water. I tried a few sensors but it not fit into my main goals.

1. HC-SR505 PIR Motion Sensor Module - it detects only motion and I can't setup a distance of detection for it so it triggered not only when cat is moving but anybody in a range.

2. A few proximity sensors - the main problem that they has small angle from 1° to 45° but the main idea is good if cat in range starting from 30cm water is on if he is gone water off.

I start thinking about cat collar with rfid transponder but I want to avoid this solutions as much as possible don't want to put collar to my buddy)

I will appreciate any advices and Ideas!

Thanks

alanesq
Posts: 43
Joined: Thu Dec 14, 2017 8:38 pm

Re: How to detect objects in range of 30 cm (180/360 angle)

Postby alanesq » Wed Jan 13, 2021 8:15 am

Could you have a platform in front or around the water bowl which acts like a pressure mat and pushes a micro-switch when the cat stands on it?

Infra red beam which triggers when broken?

Ultrasonic distance sensor? i.e. HC-SR04 (I don't know if cats can hear them?)

BTW - There is a similar thread here on the Arduino forum: https://forum.arduino.cc/index.php?topic=168076.0

Agree007
Posts: 84
Joined: Mon Sep 18, 2017 7:11 pm
Location: Copenhagen

Re: How to detect objects in range of 30 cm (180/360 angle)

Postby Agree007 » Wed Jan 13, 2021 12:16 pm

What about using a esp32 Camera with 180 angel linse and 'face' Detection ?

istokm
Posts: 21
Joined: Thu Jun 25, 2020 12:11 pm

Re: How to detect objects in range of 30 cm (180/360 angle)

Postby istokm » Wed Jan 13, 2021 3:46 pm

You could try some special passive IR sensors from Kemet. I haven't tried them yet, but from what I've seen, if they offer the claimed range and focal length (60°) then It might be just perfect (and assuming animals can trigger them). I've got a few, just forgot to buy the tiny pitch JST connectors for them... I might receive them in roughly a week, so If I'll have time to play with them I'll post my findings here.
They've got a full lineup, but this is one of the promising ones:
https://www.tme.com/us/en-us/details/ss ... ors/kemet/

This is the connector you'll need to connect to it without soldering: https://www.tme.com/us/en-us/details/sh ... -00mm/jst/

Agree007
Posts: 84
Joined: Mon Sep 18, 2017 7:11 pm
Location: Copenhagen

Re: How to detect objects in range of 30 cm (180/360 angle)

Postby Agree007 » Thu Jan 14, 2021 9:58 am

You can also try RCWL0516 radar sensor, it works 360 on people, large range but might fits the cast.

InvaderZim
Posts: 1
Joined: Fri Jan 15, 2021 6:07 am

Re: How to detect objects in range of 30 cm (180/360 angle)

Postby InvaderZim » Fri Jan 15, 2021 6:18 am

As suggested use an ESP32-CAM board.
The code under object_detection contains a choice for cats.
https://github.com/espressif/esp-face/t ... _detection

Finally design an enclosure to only allow the cam to see an area you are interested in.

OllieK
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Joined: Mon Jan 18, 2016 8:08 am
Location: USA, PA
Contact:

Re: How to detect objects in range of 30 cm (180/360 angle)

Postby OllieK » Mon Jan 18, 2021 2:18 am

My recommendation is an array of HC-SR04 sensors. There is a challenge that with a simple setup, the distance cannot be measured simultaneously by multiple sensors due to crosstalk. An easy solution for this is
  • Send a ping with one sensor
  • Wait up to 100 ms, to detect possible responses by all sensors
With this arrangement, you can detect both the distances of the objects and the relative positions. You can detect the left to right movement and toward and away from the sensors.

If the academic accuracy is not required/desired, then you can just ping one sensor at the time and wait and response for that before using the next sensor.

Arthur1
Posts: 1
Joined: Tue Jan 19, 2021 7:19 am

Re: How to detect objects in range of 30 cm (180/360 angle)

Postby Arthur1 » Tue Jan 19, 2021 7:20 am

Thanks for the update and quick reply. I'll be sure to keep an eye on this thread.

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