Loublet Schematic

On occasion it may be useful to know when a visitor has called in your absence. This is especially true in the case of an enforced absence when a visitor is expected. Confusion reigns supreme on these occasions.
The circuit here helps to rectify the ’ situation by providing a memory for the doorbell. On your return a LED will advise you whether or not a visitor called. The circuit is powered by the bell transformer via diode D1 and capacitor C1. This provides a d.c. voltage level sufficient for the memory’. Under normal conditions (with no one ringing the doorbell) transistor T1 will be switched off and T2 will be conduc- ting to provide a form of latch for T1. Obviously LED D3 will never light under these conditions! Now our visitor arrives! With a joyful cry of Avon calling’ they press the doorbell — only to lapse into total embarrasment when there is no answer! However our circuit now leaps into action. Via D2 and R 1, the doorbell switch S1 provides a base drive current to T1 which . switches off. T2 and, in passing, i LED D3 on. `&low thm transistor i ’latch’ (T2) swings the other way and T1 is held on by the current path to the positive supply through S2 (normally closed) R5 and R6. The unfortunate visitor goes away totally deflated but the LED will indicate his past presence’l On your return the LED will be noted and the circuit reset’.

This is carried out by simply pressing S2 which breaks the base currents path holding T1 on causing this transistor to switch off. In doing so the LED will be switched off and T2 will be switched on. The ’latch’ will be back in the original position where T1 is held off by the fact that R5 is effectively in parallel with R2. A further refinement would be to provide an automatic reset when the front door is opened. ln this case S2 is a switch operated by the opening door. However the LED must then be mounted outside the door (poss- ibly in the doorbell switch housing) or the LED will be off by the time you get into the house to look! On the other hand a second circuit could be built as a ’memory’ for the automatic’ memory and then it would be no problem to open the door! This second circuit will of course require a reset switch!

IR Transmitter Circuit
A simple IR transmitter schema is given which uses Continuous IR rays. The transmitter can emit IR rays up to 5 meters if the IR LEDs are enclosed in black tubes.

Virtual cell phone battery is a replacement cell phone batteries for those of you who use the phone as a modem. Including myself, who use the phone as a modem HAIER d1200p internet.  Why must use this virtual battery. For those who surf hobby "full time" with a phone modem, would know the problem, the battery gets hot and fast reply wasteful even worn out.

This tool is a good solution to keep and care for our cell phones from the possibility of damage from over-charging its battery.I created a virtual battery works as follows:We take the source of its power supply from the USB port because the port is very easy and simple to use and simply provide a standard current source when the phone is online (500-750mA).

The workings of the circuit is as follows:Diodes or diode 2Amper in 5239 this standard to provide a useful addition to the polarity of the voltage which is also a component of protection against misuse. You can just use a 1 Amp diode (IN4002-4007). I use the IN 5239 is due to be durable, more resistant to heat.4v3 zener diode IN4007 and configured to create a portal voltage of 5V (4.3 + 0.7 volt zener Vin4007) and is useful as a protection system against possible voltage spikes in the event of damage to the CPU.220nF capacitor as a stabilizer and a substitute for the original battery cells.

The following also 100pF capacitor to smooth and filter the dc current through the diode 5239 which came out of the induction logging.Configuration between zener4v3, IN4007 diode and C 220n form a cell replacement from the actual battery cells, because the battery was actually a capacitor which had a large capacity.You can just remove the three components mentioned above. although it can work fine .

But results are not as good as that use virtual cell (replacement), which certainly was the security which we have to think to avoid the things which are not in want.Making way is to use an old cell phone batteries which have been wasting his cell, a raft of this circuit and the solder terminals on the batteries with the polarity distinguished. Make two holes for the cable to the jack / USB jack.

 Determine the length of cable required to taste and use stranded cable with a diameter of at least 1mm.If some type of cell phone batteries are very thin, use a small box for this circuit and connect the two wires to the output voltage again for hp battery casing. Or also if you do not have a former battery casing, use alligator clips to the battery terminal on the phone .. Pin the middle of the virtual pin replacement battery is BSI (Battery Size Insdicator) is useful for HP Nokia.

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