Object detection/counting sensor recommendation

Projects General Guidance
1

I need to detect "passing" objects in an outdoor setting (temperature variation, partial shade, etc) but semi protected. The objects are likely to be a different temp then the surroundings and distance from sensor will be 4-18". What sensor would you recommend?

OK, OK, here's the project: I want to teach my dog to use a toilet (a 5 gallon bucket in the ground with an appropriate "seat"). An automatic treat dispenser would assist in the training. I need a sensor to put in the bucket, under the seat that would detect the passing poop and perhaps pee.

I was looking at PIR such as the http://www.parallax.com/Store/Sensors/ObjectDetection/tabid/176/CategoryID/51/List/0/SortField/0/Level/a/ProductID/83/Default.aspx, but it takes 20 sec to warm up (this is workable by activating when there is motion in the area with a 2nd PIR or being one all the time) and has a range of 15-30 ft.

  • Will it work in the 4-18" range?
  • Will it work on passing urine?
  • Will it detect poop of a different temp than a rock (although if he starts dropping rocks in there, he deserves a treat)?

Other/Better sensor recommendations?

2

take a look at thermocouple, also there is a good thread "cheap thermocouple" on this forum

3

Thank you your the reply. Can you elaborate on how I would use a thermocouple for this project?

4

sorry not thermocupple but Temp IR module. they have a name that i cannot remeber...

here a sample project: http://www.instructables.com/id/Build-an-Arduino-based-thermal-scanner/