hi todd,
As you are aware there are lots of A/V channel selectors/scanners available.

Depending how far away from the scanner you want the remote push button to be, you can attach extension wires to the switch inside the scanner.  Add a low value resistor in series with high side of the button and a 0.1uF cap across the switch in the box.

I have extended my switch about 15mtrs and it works OK.

hi,
Double left mouse click on a link, [as shown in your thread]

You will see a list of three file addresses, click the one you want.

Their page will say 'if want to download' scroll down.

you will a grey button marked 'FREE', click that.

Then you select a radio button, thats the little white button, when you click on the button you want a 'dot'
will appear in the white button.

If you just glance up the page. it will tell you which file you have selected.

Further down the page you will see the DOWNLOAD button, click that

enter the 'coded' ID into the white text box...

and that should get the job done.

You will need some way of unpacking/unzipping the RAR file, you can get free ones on the web, Google!.

hi rotclues,
A laser powerful enough to cut thru cardboard is far too dangerous for home project.

I would recommend that you download and study the potential hazards from ANY laser device.

Why do want to cut thru cardboard with a laser??
 

hi,
The large blue capacitor is connected to the 'line' [phase] of the incoming mains supply.
The design uses the capacitive reactance of the cap to limit the current flowing that low value/hi-watt resistor.
You can work out the current flowing in the resistor, by using Xc= 1/ (2 *pi *  Freq * Cap)
Knowing your local mains supply 110Vac or 240Vac at 50/60HZ depending where you live.

The voltage across the resistor is connected to the FWB.

I traced thru a simliar device a few months ago, it takes less than 30 mins to produce a working sketch.
There are zener diodes and a sometimes a 5Vreg for the sensor chip.

Use the sketch to show you the best connection point on the pcb for your 24Vdc.

CAUTION: when connected to the mains supply the pcb and components are NOT isolated from the mains.

Lets know how you go, post your sketch if you need more help.

The 2 boards that are blowing fuses, have you done a resistance check on the output pins.
I sounds as though you have short on the boards, especially as they blow with no battery connected.
Do you have a circuit you can post, it will make it easier to suggest a repair.

Are the 3.6 Vbty  for mobile phones?

output power is 1.25W. we used 10E,1w fusible resistor. it got blowed & diode in the bridge rectifier connected in the neutral path also got blowed.then we used 20E,1W fusible resistor, again same thing happened. can u assist me what to do further? ther e is no current meter. my question was is there any relation b/w primary peak current to choose the value of fusible resistor or fuse. if not how to calculate fuse value.

Hi,
If its blowing the bridge rectifier, the problems not with the fuse link.    I would suspect you have a short on the output of the charger. Have you tested across the output terminals with a ohms meter. [ WITH THE MAINS POWER DISCONNECTED]

Also, does it blow fuses when no battery is connected to the output??

Also, is the charger rated at the same voltage as the battery, example:  12Vcharger, 12Vbattery??

Also, is the input mains selection for the transformer set for you local mains supply voltage???

hi,
I would not normally fit a fusible resistor in a battery charger, a standard, slow blow fuse would be OK.

If its a typical battery charger I would expect a 5 or 10Amp fuse would be OK.

Does the battery charger have a current meter??

>> relation between the  peak primary current?

I'm not sure what you are comparing with peak primary current?

hi pier,
If you have a spare slot in your PC, you could get anotheer Parallel port pcb fairly cheap, use LPT2.

Can you try connecting YOUR printer to a friends PC for a test and vice versa?

hi,
Your question is like asking what size fuse shall I use??

Its not possible to suggest a 'fusible link' without knowing more of the application.

If possible, post a drawing of the circuit you want to protect.

hi euro,
You could consider using say, HEF4013 dual 'D' type flip/flop.[ with a transistor to drive the relay]

Positive pulse ON/OFF, they also have a RESET pin. Use a simple R/C on the RESET pin in case of a mains
blackout.

Your 4011, could restart in any state.

hi euro,
You could easily construct a logic circuit using a couple of transistors and a standard relay.
The relay would work like a bistable type.

With the low current required for the transistor/relay bistable, you could have the transistor bistables
in a central control box, driving the remote relays.

With all that water around, dont forget the Residual Current Circuit Breaker RCCD, in the mains supply.

hi euro,
You can buy logic ic bi-stables, not very expensive, the bistable  output would 'latch' the AC module.

If you bury electronics, you should use IP68 rated boxes/enclosures, pay special attention to earthing and use a RCCB.

Whats the system for?

hi euro,
You can buy small encapsulated solid state modules for AC control.
There are different types that can switch from 2 Amps thru 10A at mains voltages.
They are fully isolated and rated for mains voltages.

The control voltage is Vdc from +3V thru +24Vdc, with a very small control current.

Hope this helps.

hi,
There are pressure sensitive resistive devices, 'Quantum Tunnelling Composite Pills' QTC.
They are small pads about 4*4*1mm thick. [thin enough to fit in a boot]

The resistance of the pad can change from 10megOhm to 10ohms with applied pressure.
Force Range 0 to 100N
Lifetime > 10^6 compressions.
Max current 10Amp, Op Voltage 0 to 40V.
Op temp range -20 thru 120C
Humidity 0 to 100% [ ideal for a sweaty environment]

UK price