Author Topic: Adding an AC adapter to a cat toy  (Read 5463 times)

chucklesmcgee

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Adding an AC adapter to a cat toy
« on: December 21, 2012, 03:19:12 PM »
So my cat really loves this cat toy:

http://www.amazon.com/Moody-Pet-Fling-ama-String-Motorized-Interactive/dp/B001MVDCY2/ref=sr_1_5?ie=UTF8&qid=1356126149&sr=8-5&keywords=cat+door+toy

Problem it is runs on 3 AA batteries and can't be turned off automatically. I'd like to be able to connect an AC adapter to the battery terminals and then plug it into a timer unit in my wall. That way I can have it turn on randomly for 5-10 minute intervals when I'm away to keep my kitty amused.

What exactly do I need to do this? Already have the toy and an unused timer unit sitting around. Are there any sort of AC adapters with alligator clips I can get? I don't know exactly what I should be searching for so it's tough. Also I don't have a soldering gun.

Daley

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Re: Adding an AC adapter to a cat toy
« Reply #1 on: December 21, 2012, 04:07:15 PM »
Guessing the three AA batteries are wired in series?

If that's the case, all you need is a 4.5V 1000mA DC power brick at most, and I'm not even sure you'd need a quarter of that amperage, and the voltage is probably at least a little flexible.

Theoretically, you might be able to just butcher an old used USB cell phone charger for the job and wire it directly. If you want to have better motor speed control, it might not be a bad idea to throw a cheap variable resistor into the wiring to control motor speed with this setup. I think Radio Shack still has that sort of stuff.

As for providing power connections, you've got two options... if you want to make the mod permanent, just ensure you've got the right polarity on your DC leads and solder to the two key battery tabs in the toy. If you'd prefer to leave it convertible back to battery, use some wooden dowel chunks the same size as AA batteries bundled together in the battery holder and use a couple screws placed at the key terminal points to connect the wires to to make contact...

...make sense?

chucklesmcgee

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Re: Adding an AC adapter to a cat toy
« Reply #2 on: December 22, 2012, 08:06:56 AM »
Guessing the three AA batteries are wired in series?

If that's the case, all you need is a 4.5V 1000mA DC power brick at most, and I'm not even sure you'd need a quarter of that amperage, and the voltage is probably at least a little flexible.

Theoretically, you might be able to just butcher an old used USB cell phone charger for the job and wire it directly. If you want to have better motor speed control, it might not be a bad idea to throw a cheap variable resistor into the wiring to control motor speed with this setup. I think Radio Shack still has that sort of stuff.

As for providing power connections, you've got two options... if you want to make the mod permanent, just ensure you've got the right polarity on your DC leads and solder to the two key battery tabs in the toy. If you'd prefer to leave it convertible back to battery, use some wooden dowel chunks the same size as AA batteries bundled together in the battery holder and use a couple screws placed at the key terminal points to connect the wires to to make contact...

...make sense?

Yeah, ok that makes sense. I don't have a soldering gun, but I can probably rig up something with the dowels. I'll see what I can whip up over the next few days.

chucklesmcgee

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Re: Adding an AC adapter to a cat toy
« Reply #3 on: December 22, 2012, 09:01:12 AM »
Hmm... so all my phone adapters are USB wall adapters.

How much does voltage matter here? The toy does have a pretty reasonable tolerance and range I'm guessing, and also has two speed setting already available.

Could I use a 6V 500ma AC adapter? Like this one:http://www.ebay.com/itm/6V-500mA-AC-Adapter-Battery-Charger-w-Alligator-Clips-/200600186004  Then I could just clip the AC adapters straight on and not have to worry about stripping or soldering.

Alternatively, could I just get this AC barrel connector to alligator clip connector and clip it onto whatever available AC adapter I can find?

Nords

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Re: Adding an AC adapter to a cat toy
« Reply #4 on: December 22, 2012, 09:12:43 PM »
How much does voltage matter here? The toy does have a pretty reasonable tolerance and range I'm guessing, and also has two speed setting already available.
I don't know anything about this toy, and I hate to interrupt a good engineering-geek conversation with a practical question, but what's the voltage tolerance and range of your cat?  Is there any way it can come in contact with the existing wiring or the modified power source?

Daley

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Re: Adding an AC adapter to a cat toy
« Reply #5 on: December 23, 2012, 02:25:19 AM »
Hmm... so all my phone adapters are USB wall adapters.

How much does voltage matter here? The toy does have a pretty reasonable tolerance and range I'm guessing, and also has two speed setting already available.

Could I use a 6V 500ma AC adapter? Like this one:http://www.ebay.com/itm/6V-500mA-AC-Adapter-Battery-Charger-w-Alligator-Clips-/200600186004  Then I could just clip the AC adapters straight on and not have to worry about stripping or soldering.

Alternatively, could I just get this AC barrel connector to alligator clip connector and clip it onto whatever available AC adapter I can find?

Rethinking things, if the toy is already wired up with a speed regulator and not knowing the quality or rating of cheap Chinese components that were thrown into the mix or the wiring schematics, I can only err on the side of caution with my advice at this point and assume that the device is designed to expect and operate on 4.5V 1000mA only (4.5W output), assuming the batteries are wired in series. +/-15% of expected tolerance is usually fine in these sorts of situations unless you're dealing with delicate electronics (which you aren't). Theoretically, you'd probably be fine (if not a bit underpowered - 6V*0.5A=3W output) with that, but underpowering some motors can also be problematic, so your fast setting would probably become slow and your slow a cranky motor.

By the way, for anyone interested... it's easy to work out voltage and amperage requirements of battery devices for these sorts of projects. General rule of thumb on average specs for AAA through D cells is 1.5V 1000mA per. If they're wired in series (end to end), multiply the voltage by the number of cells. If wired in parallel (side by side matching polarity), multiply the amperage by the number of cells. A count of four AA batteries can yield one of three power configurations - series: 6V 1000mA, parallel: 1.5V 4000mA, parallel+series: 3V 2000mA. Three AA cells will only provide one of the two following power configurations - series: 4.5V 1000mA, parallel: 1.5V 3000mA. Details with diagrams here. It's important to know how the batteries are wired when you make these calculations with most things, though with motor use, they'll all provide the same wattage.

I don't know anything about this toy, and I hate to interrupt a good engineering-geek conversation with a practical question, but what's the voltage tolerance and range of your cat?  Is there any way it can come in contact with the existing wiring or the modified power source?

As a cat owner, I had several thoughts and reservations about the whole thing from the safety of the toy in general to the safety of wiring it with something resembling part of the very toy being modified, but I've learned my lesson with that sort of thing and him. For the sake of peace, I'll just share what he wants to know and leave it at that.
« Last Edit: December 23, 2012, 02:35:27 AM by I.P. Daley »

chucklesmcgee

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Re: Adding an AC adapter to a cat toy
« Reply #6 on: January 13, 2013, 04:29:08 PM »
Update: It works! Bought an ac adapter with alligator clips for $7.65 on Amazon. 6V/12V, 500 ma. Rigged it up. The battery adapter door still closes. At 6V it runs about as fast on the slow mode on the adapter as the fast mode on batteries- cat loves it! I put it on a timer to turn on for 10 minutes or so an hour during the afternoon and my cat gets a kick out of it! I've wrapped the cord over and through the door so it's nowhere near the string or his paws.

Thanks for all your voltage help!

Daley

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Re: Adding an AC adapter to a cat toy
« Reply #7 on: January 13, 2013, 05:32:38 PM »
Thanks for all your voltage help!

Glad it worked, and glad I was of help. :)

NumberJohnny5

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Re: Adding an AC adapter to a cat toy
« Reply #8 on: January 15, 2013, 03:08:30 AM »
By the way, for anyone interested... it's easy to work out voltage and amperage requirements of battery devices for these sorts of projects. General rule of thumb on average specs for AAA through D cells is 1.5V 1000mA per.

You should be able to go a bit lower without hurting anything.  Rechargeable batteries output around 1.2 to 1.25 volts (they can spike up closer to 1.5 fresh off the charger, or overcharged, but quickly drop to ~1.25 where they sit until nearly depleted).  Anyways, I multiply the number of batteries by 1.2 and again by 1.5, and try to get an adapter somewhere in that range; so four batteries means I'm looking at between 4.8v - 6v.  So if I had a 5v adapter handy, I'd wire that up.  Also, while you want to get pretty close as far as volts, as far as amps it's good to note that you really can't have too much.  So if your device needs 100ma and you only have an adapter that outputs 500ma...that's fine.  Too many volts can kill a device...but too many amps is not a problem.