Sajee tronics

If the circuit is not working, remove the potential divider resistors connected to the 9 th  pin of both 74165 ICs and connect the 9 th  pin of both 74165 ICs to corresponding digital pin of arduino mega directly without any resistors. That is, connect 9 th  pin of 1 st  74165 to digital pin 12 of arduino mega and 9 th  pin of 2 nd  74165 to digital pin 10 of arduino mega. From the circuit, it is clear that A – H pins of both 74165s is connected to 5V through pull up resistors of 1K. Pull up resistors helps to keep the state of A – H pins of 74165s to HIGH when the press button switches are not pressed. Similarly, when the press button switches are pressed, corresponding pins of 74165 get grounded through the press button switches. That is, state of that pins will become LOW.  Pin out Diagram of 74165 Pin out diagram of 74165 is given below. 74165 has 16 pins out of which eight pins (A, B, C, D, E, F, G and H) are paral...

How the Pet Microchip Works The basic technology behind pet microchips traces back several decades. But, it wasn't until recently that the devices became cheap enough to hit the mainstream pet market. A pet microchip uses  radio frequency identification (RFID) technology. RFID, as the name implies, uses  radio  waves as a medium to transmit information. An RFID tag stores data and, using  electromagnetic  forces for power, communicates that data to a device that interprets it. If you're curious about this process, read  How RFID Works . RFID tags come in different forms. Microchips in animals don't need to actively transmit information; they just hold information (a unique identification number for the pet). This type of tag, dubbed a  passive RFID tag , has no  battery  and no internal power source. Rather it sits completely inert in the animal, waiting to be read. A microchip capsule is roughly the size of a grain of rice and inc...

Hi,I recently designed a sort of "library" in order to make easier to play exact notes on arduino with the buzzer. I included the frequencies of the notes (pleasant to be heard) with #defines . I then defined the value of the BPM ( you can modify it obviously) and according to that I defined the note values ( the most commonly used ones). With this defines you can easyly play a note with the command "tone" like this: tone(pin, note, duration) Code : /* Play Melody  * -----------  *  * Program to play melodies stored in an array, it requires to know  * about timing issues and about how to play tones.  *  * The calculation of the tones is made following the mathematical  * operation:  *  *       timeHigh = 1/(2 * toneFrequency) = period / 2  *  * where the different tones are described as in the table:  *  * note         frequency     ...