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Showing posts from October, 2016

How to make a simple audio pre-amplifier

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I saw a comment on my video that he wants a high gain audio amplifier (1000 times or 60 dB voltage gain!!!). However, the most commercial power amplifier IC has maximum fix gain around 200 times (lm386) that far from 1000 times voltage gain and the problem when you make high gain amplifier is the high-frequency roll-off problem.The solution to the problem is making pre-amplifier that has very low distortion, wide bandwidth and it can amplify audio signal around 10 times or 20 dBs and send the audio signal to a power amplifier (the power amp IC he uses is tda7052 that has 40 dB or 100 times voltage gain). When combining voltage gain of the two amplifiers, he will get 1000 times voltage gain audio amplifier!!!


The method is easy and uses minimum electronic components Audio preamplifier circuit diagram.




Electronics component list:IC 1 = NE5534(op amp ic)

R1,R2,C3 are amplifier gain control by negative feedback, the formula is Gain = 1 + (R2/R1)

R1 = 1 kilo-ohms
R2 = 10 kilo-ohms
C3 = 47 uf/16 v…

Arduino project | how to make a contactless thermometer

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This Arduino project: a contactless thermometer is good for anyone who wants to measure temperature from any object without touching it. The infrared sensor detects infrared radiation that emitting from an object and convert the value to digital data and sent the data to Arduino board via I2C interface. The sensor I use in this project is mlx90614,infrared and ambient temperature sensor. It can measure a wide range of temperature from -70 to 380 °C for object temperature reading and the sensor also measure ambient temperature from -40 to 125°C. 

Mlx90614 module read an object temperature and ambient temperature and send both outputs at the same time. 

The sensor module cost around 3 - 4 $ from eBay free shippingworldwide!!!

All you need for this project are Arduino unoR3,mlx90614 module,20x4 I2C display and jumper wire.

Below is temperature sensor wiring diagram:

  MLX90614 wiring diagram   VDD ------------------ 3.3V   VSS ------------------ GND   SDA ------------------ SDA (A4 on older boar…