Monday, July 28, 2014

Guitar Fuzz Effect

Welcome back! Anyone who plays guitar for a long time knows this fuzz effect. It's kind of a vintage effect but it still is cool. This fuzz effect module can be bought but making one is easy and fun. In this post I'm not going to post a diagram for making this. Hope you will enjoy it.

Diagram:


Note:

1. LM741 is a very basic OP-AMP. You replace it with a better one for better performance.

2. The Input and Output 0.47µF capacitors can be replaced with lower valued capacitors for more Treble response.

3. For more Bass response a small valued capacitor can be added in parallel with the 1MΩ resistor.

4. 1MΩ resistor can be replaced with a variable resistor, which will give you the option to control the amount of Fuzz.

5. If the output volume level is too low, you can use a small amplifier to boost it up!

6. This circuit runs on a very small amount of current so standard PP3 9V battery or Six AA cells should be fine for powering it up.

7. It is a very small circuit so it can be built directly into the guitar.

8. An on/off switch can be added alongside a bypass switch which will bypass the audio to the female jack directly from the pick up.



There is just lot to tinker with this circuit so make one and see what you can do with it.
Good luck!

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AC Live Line Detector

Good Morning everyone! Hope everyone is doing great! Now I'm going to post a very small diagram that can be used as an AC main line detector even if it is buried under plaster. 

So what do we need?

1. CD 4017  Decade Counter with 10 decoded outputs.
2. 0.1uF non-polar polyester type capacitor. (can be replaced with a 47uF electrolytic)
3. Red LED.
4. Single Pole Single Throw(SPST) Press Button.
5. Probe made of 5-20cm long, stiff insulated piece of wire. Can be used 15Amp cables for this.

Now the diagram!

Live Wire detector



How it works?

To understand how this circuit is going to work we have understand the purpose and action of the IC CD 4017. In simple word #14 pin is the input clock pin for this IC, when it gets a clock it starts counting which means it will give output to its 10 decoded output pins one by one. So a 100Hz clock will result in each output pins giving a 10Hz output. 

#3 is one of its output pins, you can use any other output pin.

#16 Pin is for supplying positive voltage and #8 is for negative or ground reference.

#15 pin is the RESET pin, we are keeping it low so that the counter keeps on counting.

#13 is for clock inhibit, we want to advance the count one step at the positive clock signal transition. For that we have to keep this pin at low. So we hook it up to the ground reference point.

If the probe is brought closer to a live wire, capacitive coupling between the live wire and the probe clocks the counter. and causes the LED to flash, and as I said earlier the any of the output pins will get only 1/10th portion of it(as it has 10 output pins so yes that's logical) so the LED will flash 5 times in the 50Hz 220V line and 6 times in the 60Hz 110V line.

Keeping it away from the Live wire will eventually lower or breaks the capacitive coupling and thus the counter will stop and the LED will turn off.

Making The Probe!

5-20cm long and stiff insulated piece of wire can be used. Usually those used in high current applications such as powering up an air-conditioner. Sensitivity of this circuit can be varied with the length of this probe.

Powering up the circuit

This circuit can run from 3V only, two AA sized battery can do this. And because of using 3V supply no need to use current limiting resistor with the LED.

It can work with up to 18V supply but going over 3.5/4V will require a current limiting resistor with the LED.

Hope it will help! Happy Experimenting.

CD 4017 Datasheet for more information.

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Wednesday, July 2, 2014

Auto Power Off Circuit To Protect Home Appliance


In this post I will be showing you how to make a simple circuit for protecting your appliances from sudden power loss and restoration. What often times happen is when the power returns the voltage level can be a bit too high. What this circuit will do is once the power is gone it will keep the load off until you manually switch it on. You can modify this circuit in many different ways.


What we will need?


Transformer: 

1 12-15V or anything suitable for chosen relay.

Diode:

5 1N4007

Capacitor:

2 100μF 25V
1 0.1μF 100V

Regulator:

1 7812

Relay:

1 12V SPDT relay.

Switch:

1 Momentary switch.



Circuit Diagram



Mechanism:

When the 220V AC IN is hooked up to power source, the load won't turn on because one of the wires is connected to the Normally open terminal of the relay. If we hit the "Press Button" once it will provide power to the load and high side of the transformer momentarily. But in the mean time the relay will turn on as the power was available for the transformer to drive it. If the press button is released afterwards the load will continue to run.

But if the main 220V AC IN is lost the relay will automatically go to normally closed and thus if the power is back again the load won't turn on unless the press button is pressed again.

Note and Warning: 

1. As this circuit has 220VAC connection with it make sure to be careful.
2. Before connecting this circuit to AC main power check the circuit thoroughly for shorted connection or wrong connection.
3. Before changing anything remove AC main power.
4. Make sure to use a relay that can handle the load you want to turn on.
5. All capacitors should be rated higher than source voltage. If you use 5V Relay and power supply 16V Capacitors will be fine.
6. Regulator 7812 shouldn't be that hot. In case its hot, attach a heat-sink to the regulator with some thermal paste.
7. If you don't want to make a full circuit you can simply use a 5/9/12V ready made power supply with the relay. Make sure to put the diode that is with the relay. Make sure to use current input voltage for the relay as well.
8. Press button should be such that it will withstand the load current.
9. Use Neon or LED indicators if you want.


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