inexpensive & elegant release timer

Ideas and instructions how you can make your own bondage toys.
xt
**
Posts: 82
Joined: 20 Dec 2006, 09:12

Re: inexpensive & elegant release timer

Post by xt »

Well, that's funny: just for kicks I looked at the charger I'm currently using, and it says 20V! (For a newer Lenovo.) So yes, I will make sure to closely check whichever other power supply I intend to use...
OrgasmAlley
****
Posts: 515
Joined: 18 Nov 2012, 17:43

Re: inexpensive & elegant release timer

Post by OrgasmAlley »

Any electronics place should have a wall wart 12VDC 500 mA power supply for a song... or a few bucks, if they're not musically inclined ;)
User avatar
Sir Cumference
Moderator
Posts: 1606
Joined: 29 Jan 2012, 22:00
Location: Scandinavia

Re: inexpensive & elegant release timer

Post by Sir Cumference »

xt wrote:Hello All,

Along the lines of this discussion, I recently purchased an "FRM01" timer (example here):


http://www.dhgate.com/store/product/frm ... 78274.html


and a light-duty (2.5kg) electromagnet. I'll use it just to hold keys.

My question is, to power the set-up, instead of using a 12V battery (which I'd either have to go out and buy, or pull out of my car, etc.), could I instead use a household ("mains") powered battery charger, which I already have? I'm not terribly well-versed with electricity, and I'd hate to burn out the two components, but isn't that what a plug-in battery charger does, convert household AC into 12V DC? I was wondering if using the lowest "trickle charger" setting (which IIRC is 6A) would be OK. All advice welcome. Thanking in advance!
I use one of these for other (completely chaste) purposes:
http://www.ebay.com/itm/0-999-seconds-D ... Swd4tTt7xj

It works like a charm, but will only give 999 seconds (16 minutes), the one you have bought is far smarter, but more complicated.
You have to find the right program, but then I'm sure it will be great.

It is worth noting, that to start my type of timer, you connect the "IN" pin (middle pin) to "+" for at moment.


An old fashioned and "stupid" battery charger, the type that is basically just a crudely rectified 12V power supply will be great.
It will deliver far more current than you are likely to need, and you can power the solenoid and the board with the same supply.

A wall wart should be nice, so will a PSU from a computer.
PSUs can deliver a lot of current. I have had experiments starting to let out magic smoke, long before the short circuit safety in the PSU was even worried.
~ Leatherworking, blacksmithing , woodworking and programming are the most pervertable skills you can learn! ~
xt
**
Posts: 82
Joined: 20 Dec 2006, 09:12

Re: inexpensive & elegant release timer

Post by xt »

Update:

Finally got around to hooking this all up, although I was (somehow) was unable to easily track down a "wall wart" at any brick & mortars. Instead, I used a combination of a "wall-to-car" charger (i.e., plugs in to house power, sends power to a 12v car charger socket just like a cigarette lighter, max output 550mA) and a 12v accessory plug, which can handle up to 5A. I wired "+" and "-" from the accessory plug to the input side of the board, and it ran fine. I then tried every combination on the output side, to the magnet, with no juice getting through. I searched around and eventually connected it just like in this video:

https://www.youtube.com/watch?v=hsDyH7OUGPg

Afterwards, both the board and the magnet were getting power, and the power to the magnet was cut exactly as the board was programmed. In extended testing, though, I noticed that the magnet became VERY hot...as in, after an hour of being powered "on", the magnet was quite literally too hot to touch for more than two or three seconds...not good.

The board draws between 5 and 30 mA, and the magnet says 0.33aH, which I take to mean 330mA. AFAIK, then, the setup wants no more than 400mA, while the power combo can provide up to 550. Anything I'm missing? Needless to say I don't want to create a fire hazard. All advice welcome again!
User avatar
FatherOfFour
***
Posts: 247
Joined: 15 Nov 2015, 17:58
Location: E.Eu: is it Europe?

Re: inexpensive & elegant release timer

Post by FatherOfFour »

Hi,
400mA at 12Volts = 4.8Watts.

To get something at 60-70C, with 5w, it has to be pretty well isolated or small.
Hard-disks suck almost 10w (8w the green ones), and they do not get that hot...

I'd suggest to seek for ways to dissipate that heat (some sheet of metal), or use a series resistor (a ceramic one , few watts worth)
Or some nickel (heater) wire through one of the toys... 1-2watts should mimic body heat...

Have fun, use Power,
f4
xt
**
Posts: 82
Joined: 20 Dec 2006, 09:12

Re: inexpensive & elegant release timer

Post by xt »

F4,

Thanks for weighing in. As it turns out, yes, the magnet is *very* small -- it's less than 1 in. / 2.5cm across! But it can definitely hold some weight. I should be able to conjure up some cooling fins using sheet metal, as you said; great idea. TTFN!
slave2YourNeeds
*
Posts: 2
Joined: 18 Jan 2016, 15:38

Re: inexpensive & elegant release timer

Post by slave2YourNeeds »

First let me say that i have been an electronics engineer for over 50 years so what I am sharing is based upon sound engineering principles.

Using a battery with a small charger is definitely a plus because it rules out power failures as a possibility. A good type of battery are alarm batteries which are available as 12V units with 6 Amps or more. One sources is Home Depot and you can see such a battery here:http://www.homedepot.com/p/Mighty-Mule- ... /203642200.

As for the battery charger you really do not need much more of a unit than this unit seen here:http://www.gruberpower.com/6-volt-12-vo ... oCyBjw_wcB
User avatar
Sir Cumference
Moderator
Posts: 1606
Joined: 29 Jan 2012, 22:00
Location: Scandinavia

Re: inexpensive & elegant release timer

Post by Sir Cumference »

Welcome aboard S2YN
:hi:
~ Leatherworking, blacksmithing , woodworking and programming are the most pervertable skills you can learn! ~
User avatar
Sir Cumference
Moderator
Posts: 1606
Joined: 29 Jan 2012, 22:00
Location: Scandinavia

Re: inexpensive & elegant release timer

Post by Sir Cumference »

Electro magnets getting hot is a problem we've seen a lot of.

Another possibility is to lower the voltage. That will mean less force, but also less heat.


If you need to keep the system running through a power outage, the backup battery is a must.

Alternatively you will just be released if the power fails, prividing that you have designed the system to release if the power to the magnet is cut.

Designing your system to "fail safe" is a prudent strategy most of the time.
~ Leatherworking, blacksmithing , woodworking and programming are the most pervertable skills you can learn! ~
OrgasmAlley
****
Posts: 515
Joined: 18 Nov 2012, 17:43

Re: inexpensive & elegant release timer

Post by OrgasmAlley »

The simplest solution to your heat issue is to point a small 12V fan at it, wired in parallel. You don't need much to dissipate the amount of heat involved here. Something like this:

http://www.amazon.com/Gdstime-2-5cm-Sma ... s=25mm+fan

You do, of course, have a risk of heating should the fan itself fail, and you could double-up if it's a huge concern. However, we run these to cool electric motors on RC race cars... motors pulling as much as 120A or so. They're durable, and run for years.
redsonic
*
Posts: 13
Joined: 15 Apr 2009, 10:45

Re: inexpensive & elegant release timer

Post by redsonic »

your lock is UNSAFE
any wire can disconnect and you in trouble
xt
**
Posts: 82
Joined: 20 Dec 2006, 09:12

Re: inexpensive & elegant release timer

Post by xt »

Gang,

Will check at the local hobby store for the cooling fan. If they don't have one, or if the total power draw would be above what the timer board can supply, I could also use a small desk fan placed nearby.

Keeping the power on through a failure is not crucial at the moment; the lock will disengage (IOW drop the key) if the power is cut, so it is a built-in safety. Plus, of course, the ever-present ice backup...
Post Reply