Cheap electric timer

[nitro]

I have seen it called "plumbers tape". Don't know why. I have seen it in steel, galvanized steel, and copper.

ptape-2.jpeg (1.27 KiB) Viewed 1611 times

[cdinbonds]

I have seen it called "plumbers tape". Don't know why. I have seen it in steel, galvanized steel, and copper.

ptape-2.jpeg

Because plumbers use it to hang pipe. It's also known as perforated strap.

[Jadit]

...it's solid plastic wheel with no pins. It's not customizable and it came with only 1 instruction picture - turn the wheel...

Now i feel a little stupid I was putting the device in place again and when pressing it from the wheel i realized that every tiny little pin forming the wheel is actually a on/off switch. So it was actually fully customizable... awesome.

Also, what's the difference between mobile phone recharging devices and stepdown transformers or are they the same thing?

I could then basically cut the plug thing off the wire so that i'd possibly get 2 wires from inside the cable and attach them both ends of the coil?

[Dark_Lizerd]

...it's solid plastic wheel with no pins. It's not customizable and it came with only 1 instruction picture - turn the wheel...

Now i feel a little stupid I was putting the device in place again and when pressing it from the wheel i realized that every tiny little pin forming the wheel is actually a on/off switch. So it was actually fully customizable... awesome.

(Head slap, D'oh!!)

Also, what's the difference between mobile phone recharging devices and stepdown transformers or are they the same thing?

I could then basically cut the plug thing off the wire so that i'd possibly get 2 wires from inside the cable and attach them both ends of the coil?

OK, I can answer that one...
Step down transformer: AC to AC, IE: 120V AC to 9V AC... Some electronic devices use AC for power, but not the full 120V.
Phone charger: AC to DC, IE: 120V AC to 9V DC or 5V DC or 3.3V DC and maybe about 100 mA current.
Depending on what you are powering, that may not provide the power you want or need.

If no access to an old PC, check yard sales for small powered devices, or power supplies, and check the output voltages and current
rating for what you need.
If you device needs 12v @ 500mA, you can get any power supply that has an output of 12v and at-least 500mA (.5A) or greater. (more is better)

If you got, or can get, an old desk top PC, take out the power supply, that will provide you with: +5v @ 5a, +12v @ 1a, -5v @ 1a, -12v @ .5a, and 3.3v @ .1a.
Just run the wires, 1 for each color group, to a panel, (board, wire termination block...)
Either use a terminal strip (little black thing with pairs of screws for connecting wires together)
or plug-in connectors (like RCA jacks)
and connect what you are powering that way.
Now with a little creativity, you can get several different voltage choices:
Your device: red wire(positive) (+), black wire (return, ground...) (-)
24v @ .5a= (+)+12v to (-) -12v
7v @ 1a= (+)+12v to (-) +5v

OOPS, longer than planed, but you get the idea...

[lj]

I feel a sudden urge to scream very loudly!

Let's start with some basics.

A transformer produces AC (alternating current) which is useless for an electromagnet unless it is designed for it, and most are not. The Electromagnetic door-locks mostly require a DC (direct current supply) usually 12 or 24volts. I have limited experience of these, but the current requirement seems to be surprisingly low for an amazing "hold" capability.

To specify a piece of electrical kit you need to know the required voltage AND current, for example 12 vdc (volts DC) at 100mA (100 milli-amps or 0.1Amps)

"wall warts" come in a wide variety of types, from the tiny 3vdc at 100mA through to 24vdc at 5 Amps. Mobile phone chargers are simply a variation on these, and are usually at the lower end of things. Note that the safety of some of these power supplies relies on the fact that they are powering a plastic box with no external connections, they are not designed with the expectation that the user will take a pair of cutters to them!

So, simply grabbing the nearest wall-wart and hooking it up to your unknown piece of kit will result in (a) the power supply smoking (b) your kit smoking (c) you fry (d) wow, it works!

Lj's rule with electrics "if you don't know what you are doing, don't do it!"

second rule "if you can use small batteries, use them"

A while ago I got hold of an electromagnetic lock and found it would operate very effectively with a PP3 (9volt radio battery). The battery would last about 4 hours max, so a built-in safety release and very cheap to run, and no risk of mains electric shock.

[nitro]

If you got, or can get, an old desk top PC, take out the power supply, that will provide you with: +5v @ 5a, +12v @ 1a, -5v @ 1a, -12v @ .5a, and 3.3v @ .1a.

Just a quick side note. Many of the PC power supplies, especially the older ones, use switching supplies that require a minimum load to operate correctly, or at all.

Years ago I had an old PC-AT without a hard disk. This had a "hard disk load" installed in place of the hard disk, essentially a large high power resistor to provide a load for the switching supply. Just check the specs on the supply.

Also watch the new ATX/EATX supplies, the power control is logic level back to the supply through one of the pins on the power output connector. Many do not even have a real AC power switch.

[ruru67]

Been there. I had an expansion box on an old computer, which had a tape drive in it. Upgraded the drive, and it didn't light up. The trick was to put a dummy load on the 12V rail, and then it worked fine.

But in that case, I still needed a computer-type PSU with 12V and 5V outputs; it's just that the load didn't quite match the supply. For something that just wants a single voltage, a simple commodity power brick / wall wart is going to be a lot cheaper, easier to hook up and safer than trying to persuade a computer PSU to do the job, for all the reasons nitro points out, plus the fact that you have to make safe all the outputs you're not using.

Also note that a PC power supply is intended to live inside a PC chassis, so has considerably less protection against ingress of liquids and foreign bodies than a power brick with a solid plastic shell.

[Dark_Lizerd]

All true, I only brought this up because I had seen one where I was working a ways back.
It had a terminal strip mounted on the top of the case and the 12 leads ran to it.
I had never thought of doing that before...
Made one for my use at home... but mine was not a switching PS.

Or, you could pick-up a varable output power supply...

Or use a wall wart... (best idea for a non-DIY type)

[ruru67]

Or use a wall wart... (best idea for a non-DIY type)

I think the point several of us have been trying to get across is that it's the best idea (other than using batteries) for DIY types too.

A decent DIY type uses something approximating the right tool or component for the job. Doing otherwise, especially when the right part is actually cheaper than the wrong one, makes one a redneck rather than a a DIY type.

[Dark_Lizerd]

... depends on what is on hand...
But... back to timers....

[nitro]

OK, to get the timer thread going again. Another timer to check out. This one has a wired remote. Not so cheap at $21 USD. The remote might have some other possibilities.

"Leviton LT113-10W 1000-Watt Advanced Digital Plug-In Timer, 6-Foot Tethered Remote, Grounded Plug, Receptacle..."
Program all days (50 event settings per day), week, weekends; any day or combination of days.

Leviton-LT113-10W.jpg (9.76 KiB) Viewed 1477 times