## Posts

Showing posts with the label Arduino

### 7 segment display Arduino

The aim of this article demonstrate how the Arduino can run on 7-segment display.We used a SA56-11GWA which is a single display with common anode, it means that the anode is common to all digits, and to the point.
A display consists of 8 LEDs, 7 form the figure and 1 point decimal.A conversion between decimal and what we intend to show the binary information that you receive is called the BCD (Binary Coded Decimal).
In terms of hardware, each LED work individually, so each of the segments has to lead a limiting resistor, in this case, each digit has an operating voltage of 2.2V and consumes 20mA.If the voltage is 5volts, we need the resistor fall 5-2.2 = 3.8V, by Ohm's Law we can calculate, R = V res / I led R = 3.8 / 0.020 = 190 Î© +/- 20% (let's use a resistor with 220Î©).This applies to this display SA56-11GWA used as an example, other values ​​may be different, it is useful to calculate the required resistance value. DecimalTheA 3A 2A 100000100012001030011401

### Auto ranging ohmmeter using arduino

This article is about a simple auto ranging ohmmeter using arduino. The measured resistance is displayed using a 16×2 LCD display. The circuit is sufficiently accurate and uses minimum number of external components possible. Before going into the details of this project, lets have a look at the basic resistance measurement method.
Resistance measurement.
The figure above shows the circuit diagram of a simple resistance measurement scheme. Rx is the resistance to be measured. R1 is the input resistance. i is the current passing through the loop and 5V is the supply voltage. To find the unknown resistance Rx, the voltage across Rx is measured first. let the voltage across R1 be VR1. Then VR1=5-Vx. The current i=VR1/R1=(5-Vx)/R1. Since R1 and Rx are connected in series, the current through them will be equal. So the unknown resistance Rx= Vx/i. The voltage across the unknown resistance is measured using the ADC of the arduino. To be precise, analog channel A5.
Anyway this method have a …