Wednesday, June 24, 2009


This add-on circuit enables remote switching on/off battery operated toy cars with the help of a TV/video remote control handset operating at 30-40 kHz.

this circuit can be easily fabricated on a general purpose printed circuit board. after construction, enclose it inside the toy car and connect the supply wires to the battery of the toy car with right polarity. rewire the DC motor connections and fix the IR receiver module in a suitable location.

Sunday, March 29, 2009


this circuit provides secrecy when two or more telephones are connected in parallel to a telephone line. the circuit also prevents incoming calls to as well as outgoing calls from other telephones connected in parallel, except from the one lifted first.

When someone picks up the handset of the telephone connected to the original (master) phone for making an outgoing call, no dial tone is heard and the phone appears to be dead. but when call comes, the ring signal switches the SCR's 'on' and conversation can be carries out. As soon as the handset is kept on the hook, the SCR goes off and the telephone can again only receive incoming calls

Saturday, January 17, 2009

Safety First - House Security System

A low cost, invisible laser circuit to protect your house from thieves or trespassers. a laser pointer torch, which is easily available in the market can be used. the block diagram of the unit is shown. the laser torch is powered by 3v power supply is used for generating a laser beam.

A combination of plain mirrors M1 through M6 is used to direct the laser beam around the house to form a net. the laser beam is directed to finally fall on an LDR that forms the part of the reciever unit. An interruption of the beam by a thief will result into energisation of the alarm. the 3v power supply circuit is a conventional full wave rectifier-filter circuit.

The receiver unit comprises two identical step-down transformers (X1 and X2), two 6V relays (RL1 and RL2), an LDR, a transistor, and a few other passive components. When switches S1 and S2 are activated, transformer X1, followed by a full-wave rectifier and smoothing capacitor
C1, drives relay RL1 through the laser switch.

The laser beam should be aimed continuously in LDR. As long as the laser beam falls on LDR, transistor T1 remains forward biased and relay RL1 is thus in energised condition. When a person crosses the line of laser beam, relay RL1 turns off and transformer X2 gets energised to provide a parallel path across N/C contact and the pole of relay RL1. In this condition, the laser beam will have no effect on LDR and the alarm will continue to operate as long as switch S2 is on.
When the torch is switched on, the pointed laser beam is reflected from a definite point/place on the periphery of the house. Making use of a set of properly oriented mirrors one can form an invisible net of laser rays as shown in the block diagram. The final ray should fall on LDR of the circuit.

Friday, December 26, 2008


have you seen this!!!!!!

well you might have seen this in some of the auto expo's around the world. And it is Honda Mugen F154SC concept. The technical specs is something like this four cylinder with a swept volume of 1.5L and the engine is supercharged. the car comes with an upgraded engine.

Saturday, December 20, 2008

Necessity Of Cooling System

When the engine is running the combustion in the cylinders heats up the engine. But if the engine gets too hot it loses power. If the engine remains hot for a long time, that causes slight distortion in the engine parts that in turn reduces the gaps between the moving parts. That is why an effective cooling system is necessary to cool down the engine parts and the lubricating oil. There are two kinds of cooling systems: air cooling, which uses the running air flow to cool the engine, and liquid cooling that circulates coolant fluid through passages around the engine.
The mechanism underlying: A liquid cooling system uses a web of passages around the cylinder to circulate coolant through. When the temperature of the coolant around the engine rises, it is sent to the radiator (a heat dissipating tank) to be cooled by running air flow or an electric fan and then circulated back to the engine. This constant circulation of coolant constantly cools the engine. Yamaha YZF-R15 uses this kind of cooling system and is expected to continue with the job in the forthcoming models of higher range mobikes.

Tuesday, December 16, 2008

Be careful about your phone

It is a common rule that when there is a good thing, by default there is a bad thing associated with that. This applies to everything in this world. The mobile communication technology which gave us immense potential to grow had its disadvantage from the beginning. As its ability and merits are increasing, so are the drawbacks. On of the security threat was SIM card cloning where the module can be cloned and the call to the original SIM card can be received by the cloned cards and can share the same account.

Now the mobile security threat has gone a step ahead, the IMEI (International Mobile Equipment Identity) [to know your mobile IMEI number press (or dial) *#06# ] number which supposed to be unique and tamper-proof can be changed. The hackers have developed technology to change the IMEI number which otherwise can be used to track down the stolen mobile phone.

So folks better be careful with your all-in-all gadget and I whish you a happy conversation.

Monday, December 15, 2008

Wear this to keep sunstroke at bay

Heat stroke or sunstroke is an acute condition which occurs when the body produces or absorbs more heat than it can dissipate. Hyperthermia is the medical term. It is usually caused by prolonged exposure to high temperatures. The heat-regulating mechanisms of the body eventually become overwhelmed and unable to effectively deal with the heat, causing the body temperature to climb uncontrollably.

The “cooling cap” deals with the issues that almost all kinds of players face, when they are out on the ground. Heat stroke has become an issue for the people who are directly exposed to the sun. the cap having embedded cooling system with convective/conductive coolant tubes and removable gel pack helps in efficient transfer of heat from the head to the suuroundings.

1. Main frame

2. Gel pack

3. Cover

4. Cotton strap

5. Top cotton layer

6. Bottom cotton layer

7. Bottom fabric layer

8. Phase change material