Sensor

I want to set up a garden sprinkler to deter next doors cat. Can anyone recommend a suitable sensor for this? Will any of the usual security type commonly available detect a cat? I already have a suitable mains solenoid with hose fittings.

Google 'cat hose sensor' lots of purpose made ones out there.

Neil

(many security ones are designed not to detect pets - they have multiple zones and pets don't trigger as many zones as a human)

Edited By Neil Wyatt on 19/08/2020 18:23:48

I used a "Party popper", was clean out of hand grenades.

Triggered by a PIR.

If your solenoid is low voltage, use a low volt PIR..

Good luck..

All the ones I’ve seen seem to be of inferior quality and attract poor reviews, hence the decision to make my own.

I've used these LINK for the very same purpose.
Mount at the back end of a bit of waste pipe with suitable cap to provide shielding and protection.

Thanks I’ll have a look. Reading some reviews of the standard outdoor ones, many of them seem to be quite sensitive unlike the indoor ones designed not to pick up large pets.

I have used one similar to the PestBye available on Amazon. A bit cheaper than when I got mine some years ago.

John

Set it low,

But then don't be surprised if you then get rodent trouble.

A mate at work some years ago got some Tiger poop sent mail order to work. He was most upset when I wouldn't let him unwrap it in the office

Top trump apparently.

I made something similar, for dogs - used ordinary passive IR detectors to activate an ultrasound generator - used a 555 timer pair to generate a sweeping tone from 18KHz to 35kHz, into a 40watt car type amplifier, driving a horn tweeter. You should see the dogs reaction when it triggers.. Added to it eventually, a 'bark' detector ( some filters and signal amplifier) which would then trigger the unit every time the darn neighbour's dogs bark. They would sit at his motor gate, over the road from me, and bark all day, at any sound or movement. After a few days of ultrasound, the silence was a pleasure and it was very amusing to watch them slink quickly across the motor gate path to hide behind the end walls!

What I really wanted to do was make a 1KHz, 1KW tone generator and stuff it in the neighbours ear hole, rather than torment the dogs..

Joe

Nice one Joe. I wish I could build one of those mosquito devices for when the kids start screaming. The problem is at my age I wouldn’t know if it was working or not!

I am not a keen gardener but weeded and dug over a flower bed the other day, it is now a cat toilet and it stinks! My wife has invested in a hedgehog house and going by the poo on the lawn they are visitors even if they are not resident yet. I would like the cats to desist but the hedgehogs are very welcome, how can I target the cats and welcome the hedgehogs ?

Mike

Mike, Ultrasound would be the way, but does require a bit of a faff... The auditory range of a hedgehog is typically from 250Hz to around 45KHz, and domestic cats from 45Hz to 85KHz. So there is a good 30KHz gap to play with, in the range 55KHz up.

It needs to be reasonably high level , around 70 dB SPL. ( Background noise in a crowded restaurant is typically 60dB SPL). You would need around 40watts (RMS) into maybe 4 or so efficient dome tweeters, fed from a 50-80KHz tone generator....If you wish to pursue I am happy to help and provide some simple circuits, etc - you should be able to get most of the needs from the likes of Maplin, RS, etc.

The difficult part is the audio amplifier - needs to go up to the 85KHz range, and not roll off at 30KHz or something.

Many of the high power car amplifiers qualify and can be used.They are also relatively inexpensive.

The reason I have some knowledge in this, apart from the aforementioned dog dooda, is that we use a quite powerful, solar powered version of this , located at the cattle/goat kraals of rural villagers, to scare off the Lions trying for easy meals. It works very well! Unfortunately the auditory range of Lions is nicely in the range of dogs, so the villagers dogs suffer, and stay far from the kraals! Rather that than the villagers shooting/poisoning the lions when they come marauding.

Joe