Let's Make Robots!

Cat Splat!

I mentioned at the end of my tip/walkthrough on making IR obstacle detection sensors that they could be used for tracking an object and it would be great to track the cat with it and shoot it with a waterpistol. So now I'm posting it as a challenge. It's usually difficult to wash a pet anyway (not just cats) so lets make it fun!

Before anyone acusses me of animal cruelity, I like all animals (and some insects) but damn it is funny when a cat or dog is curiously investigating some new object and they get squirted for their trouble.

Make some sort of object tracking system using whatever sensors you have. Use it to aim a waterpistol at any object within a certain range. Video it tracking and squirting a curious pet. It must track the pet prior to and during the squirting to demonstrate your robots hunting ability. The funniest video wins.  It may be a stationary system or a mobile pet squirter.

I used cat splat because it rymed but any pet can compete even if its not yours.

I've had to extend the the challenge to allow for seasonal differences (Petsicles will be disqualified).

SplatBot5__small_.jpgThis is SplatBot MkI. I built him to give anyone interested in this challenge some ideas and prove it can be done easily with a reasonably cheap pump. Admittedly MkI is a bit clumsy with all that weight on top and ended up straining the servo that raises and lowers the cannon. The MkII will have the waterbottle on the chassis and a better IR tracking system, something I still haven't perfected yet.












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I bought a cheap aftermarket windscreen washer pump from Autobarn for $15. It drew 800mA running of a car battery (no water). I suspect the TAFE motor was used, abused and knackered like most TAFE equipment.
I got mine form Super Cheap Auto for about $10-$15, just cheap crap I guess. I was driving it from a bench supply with the current set to 2A max, maybe it wasn't drawing that much, maybe my supply a bit dodgy?

Eitherway, I can't compare as the pump on SplatBot is running on a 7.2V battery and draws about 800mA unloaded (no water). If it was running on 12V and pumping water it could no doubt draw in excess of 2A.

Since the pump is only on for short bursts and the NiMh AA batteries can easily put out 6A or more (i've gotten 6A from AAA) they still make a suitable pump for the challenge.

Admittedly automotive devices running off big car batteries usually don't get designed with efficency in mind. Point is that any pump mechanism may be used as long as the pressure isn't so great that it could hurt anyone or any animal.
what are the specs? How much voltage is required and what is the fluid output rate? I'm actually looking for something that can pump approx 1 ounce of "liquid" in 1-3 seconds.

Found an article that states :

"Ideally, washer pumps should deliver 38 psi output of water pressure at a flow rate of 250ml per minute.  "

which converts to 8.45 oz per minute. Saw another said 500 ml through a hose with no nozzle, whihc would give 16.9 oz per minute.

That may work. I want to make a robot bartender where you use pots to pick how many ounces of each liquid to use. Ok now to be back on track for this topic.... It sounds like this may get some distance for the cat splat challenge, but you may need to find the nozzle to increase pressure.

i think you could use whatev they use in drink machines, right?


they use pumps, don't they? 

As for the bartender, I wouldn't recommend car washer pumps for hygenic reasons plus the alcohol may cause the seals to deteriate. You may want to consider a pond/fishtank style where there is no chance of lubricant tainting your drinks. These pumps are automotive so they are usually rated at 12-15V.

As for distance, my entry will get up close and personal, I want volume over pressure plus I don't want to hurt the animal, higher pressure could hurt if it hits them in the face.

The pond/fishtank style have to sit in water, not use tubing for both in/out flow of water. If you do use tubing they have to be primed. I was going to get new washer pumps, but I can see how the alcohol would wear down parts. I'm sure there has to be some food safe pump that will work. I could also mount the bottles high and let gravity do its thing. Then I need s strong solenoid or somethign to pinch the tubes.