basmoq

Hey guys (and gals too), I just bought my new bundle of joy (or should I say my mother in law just bought) my new son a new swing thing. My problem is that I hate batteries, and only use rechargables myself, but I don't have rechargable D's and this swing only uses D batteries. There is no plug in port, which says to me that the battery companies paid Fisher Price to not include one...

On to the solution

I'm planning to wire in a plug in port on the side (the easy part), now I just have to decide on the specs for the power supply. I know that 1.5V in series adds to 6V DC, but I have no idea at all what kind of draw that motor has . Do I need a 1amp supply, 100mAh, 10amp????? it doesn't exactly state the specs in the manual, so how the heck should I know. If only I hadn't put my dad away (an electrical engineer), I wouldn't need to ask you guys, but seeing as how he and I don't talk any more, I thought I'd ask here. Any suggestions?

I'm also planning to install a switch so I can switch between battery and stationary power so I don't fry the batteries when it's plugged in with batteries still inside, can anyone suggest a wiring method to make this automatic, I know it can be done, but I'm not sure exactly how or what would be required.

Thanks all

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pattycakes

if you have to ask for directions dont bother doing it. because it is your childs saftey or you saving so you dont have to buy batts

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basmoq

hold on now Pattycakes, I said I wasn't sure what kind of amps it drew, I did not in any way imply that I'm incapable of finding out, it'd just take a lot of work and I was hoping someone had a suggestion. For that matter, my childs safety is not at risk because you only use a swing when he's being watched.

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flat5

A one amp supply will be enough or the D cells will be replaced very often.

You can measure the current required with a meter. Put the batteries in but
don't allow one contact to mate with what it wants to touch. Put a piece of paper in the way. Now use the meter, on the 2 amp range, for instance, to complete the connection the paper is stopping. The meter is now in series with the power supply and can tell you how much current is being used. Sellect an adapter 40% bigger.

I would just use a regulated 1.5 amp universal adapter. This way it can be used for any purpose in the future.

Is this device to be used outdoors or near water? Take very good care that the supply is protected from the elements. If there is a chance that 110v or 220v will find a leakage path to the "swing" then it's not safe.
For outdoor use, you might use a 6v auto or motorcycle battery and fuse.
Just recharge it as required.

Oh yes, your other question.
Use a "switched power jack" (single pole, double throw) on the swing.
When you plug the adapter in, one (of two) connection to the batteries is broken and the one from the adapter is "made".

Break one connection from the batteries to the swing.
Connect this to the power jack (the arrow one in the pic).
Connect the "common" connector on the jack to the batteries wire that you have not messed with.
Connect the switch "male" pin to where the battery wire used to go (the swing).

Be sure the voltage polarity on the switch jack/adapter is correct!

basmoq

Hey flat5, thanks a ton for the help, it makes so much sense after someone reminds me, it's just been a bit too long since I had physics to remember some of this stuff. I guess it's time to haul out my new Craftsman Digital Voltmeter!!! I'll give your suggestions a try and post my results.

As for what type of swing it is, it's a Fisher Price 3in1 Rocker swing for newborns through toddlers, it won't be used outside, and I plan to sheath the power cord so little toddler teeth cant get through it. Thanks for your suggestions and your concern.

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"There's someone out there for everyone - even if you need
a pickaxe, a compass, and night goggles to find them."

Cynthetiq

can't you just buy rechargable D batteries?

http://www.thomas-distributing.com/r...-batteries.php

I don't mean to sour your project but why not just get rechargables 2 sets of what you need so that there's always a charged set? Or do you want to do the whole Tim Allen Man thing and make the swing into a thrill ride?

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maleficent

Cyn went were I was going...
/off topic musings....

I have seen entirely too many episodes of Home Improvement... I have this vision of this turning into a Tim Taylor project and the baby swing being turbo charged and playing catch the baby, as he turns into a projectile as it goes flying out of the swing.

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basmoq

LOL, that's a great idea, except that this swing has an interesting method of pushing the swing that cuts off pushing at a specific force, allowing you to push the swing backwards while the motor pushes without placing much stress on the motor, so I'd basically have to redesign the thing to do that, but it's an interesting idea...

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cyrnel

I'd go for the rechargeables as well, for convenience and remote safety advantages. For the baby, maybe, but if nothing else I'd be tripping over the stupid cord.

If you do go with rechargeables, be careful about which one. Many D-cells are re-packaged AA's that cost more. If the mAh rating is 5000 or less for a D-cell then it's just a AA or C wrapped in a D case and will not provide much run time. Recent D-cell NiMh's supply 8000-12000mAh which should last nicely.

For comparison, high-end alkaline D-cells are rated ~12000-15000mAh.

Examples:
Eveready Energizer NiMh D-cell - 2500mAh
Eveready Energizer NiMh C-cell - 2500mAh
Eveready Energizer NiMh AA-cell - 1700, 2300, or 2500mAh
Eveready Energizer NiMh AAA-cell - 850mAh

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basmoq

the reason I decided to go with the plug in method is the under $20 price tag, and never worry convenience about having charged batteries or needing to run for alkaline. As for rechargables, I love em, but the $10 per D plus the cost of a charger to accomidate them is a little bit unreasonable when it totals to what I paid for the swing.

__________________
"There's someone out there for everyone - even if you need
a pickaxe, a compass, and night goggles to find them."

basmoq

BTW, I found that it draws a measly .3A peak, so I'm thinking that a 1 to 1.5A will be just peachy. now I just have to find out how much they run at the local elec.shop and how it compares to online prices with shipping.

__________________
"There's someone out there for everyone - even if you need
a pickaxe, a compass, and night goggles to find them."

flat5

You may have one already :-)
For this project, a cheap unregulated adapter is fine.
You can find a used one in Salvation Army type stores.
Easy way to hook it up is to solder across the battery contacts and forget about batteries :-)

One problem with NiCad batteries is you have to make sure that they are not completely discharged. You have four batteries in series. If they discharge at different rates, then one batterey (the first to completely discharge) will receive voltage through it backwords. This is quick death to a NiCad. That battery can not be fixed and can never be used again.

Cynthetiq

Yep, that's why I never use NiCads nor do I recommend them. My link goes to NiMh batteries, not only do they not have the memory issues but they also come in varying mAh depending on usage.

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basmoq

I personally stick with the NiMH, althought flat5's mention of fried NiCads is not completely correct, my dad was an electrical engineer, and what he would do is take a very large capacitor and shock the shit outa that NiCad, it was then quite well fixed. However, it didn't fix it forever, and the NiCads have a very short use life...

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"There's someone out there for everyone - even if you need
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flat5

basmoq, I said one way they fail. Zapping will not fix the battery when it fails this way.

When there is internal leakage caused by corrosion and a build up of crystals, zapping does work. The battery will still produce these crystals that touch adjacent plates (and bleed the charge away) so the battery has to be zapped again. and again.

ok. I found someone who can explain it better.
http://www.batterieswholesale.com/faq_nicad.htm#14

There are two main reasons cells fail, other than abuse. One is separator failure, and the other is degradation of the active material. The first is far more common, and the result is a shorted cell. Every time a cell is charged, the active material is redeposited on the plates. Ideally, this occurs uniformly across the surface of the plate. However, in reality, there will be bumps and valleys. When there are bumps on both the positive and negative plates are adjacent, separated only by the separator, the resistance between those two points is slightly less than in other regions of the cell. So, the current density there rises. This means that more material is deposited there, contributing to even more "bumpiness". In reality, needles called dendrites form, and given time, they can force themselves through the separator to short the cell. A cell that appears to self-discharge in a couple of days has dendrite problems, and will soon completely short out. Plan to replace the cell. Degradation of the active plate material is just a normal aging process of cycling. Both of these mechanisms are very good reasons to avoid cycling the cells after each use. Cells should live to about 1000 cycles if treated properly. Anything over that is gravy.

Q: I've seen people talk about zapping cells to revive them

A: Yup -- a quick fix it. When cells short due to dendrites, the piece of material that is actually shorting the cell is very thin. So, by forcing a huge impulse of current into the cell, one can vaporize the dendrite -- sort of blowing a fuse. This works, and can revive an otherwise shorted cell. However, it is a stopgap measure at best. First, the fact that one dendrite has formed means that another is not too far behind. Second, the material that was vaporized has now permeated the separator material, forming a resistor that shorts the plates. The cell may no longer be shorted, but will still have a poor charge retention. Besides, unless done properly, this can be dangerous as large currents are necessary.

basmoq

ahh, my mistake, thanks for the correction

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"There's someone out there for everyone - even if you need
a pickaxe, a compass, and night goggles to find them."

Smackre

when i was 8 my parents got me alittle wood workers set. it was some wood tools and a battery powered jig saw and drill. well needles to say it had no power to cut threw anything but bulsa wood. so me and my dad wired it into 110v and it blew up. i understand now why it didnt work. but back then i wasnt very smart.

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FngKestrel

Have you ever considered just using your foot to kick the swing? No batteries, no plugs, voila!

Just kidding, sounds like an interesting project. Good luck with it.

basmoq

well, I've been putting off shelling out any cash to set this up, but then I found that my wife has gone through 2 sets of D's in the past week, and only gets about 2-3 hours out of it with a set, at $5 a set, that's insane, so I'm gonna run out and do it this week.

__________________
"There's someone out there for everyone - even if you need
a pickaxe, a compass, and night goggles to find them."

flat5

I'm interested to know how it turns out.