write( 0x10) // sends 0x10 (hex) 00010000 (binary) to control register – turns on square wave write( decToBcd(second)) // 0 to bit 7 starts the clock Convert binary coded decimal to normal decimal numbers Convert normal decimal numbers to binary coded decimal Int red = 9 // LEDs connected to these pins as you might want to PWM them to alter brightness
Sim900 sms mac terminal code#
John Boxall August 2010/6th April 2022 – ĭS1307/i2c timekeeping based on code by Maurice Ribble 17-4-2008 – The LED was tested with this simple sketch: This is quite easy, the formula is: resistor (ohms) = voltage drop / LED current So if you have a 5V supply, and LED that needs only 2 volts, and draws 20 milliamps (0.2 amps), the calculation will be: resistor = (5-2)/0.02 = 150 ohms. Each LED is going to be different, so to ensure maximum brightness without causing any damage you need to calculate the appropriate resistor values. Red, green and blue to D9, D10 and D11 respectively.
The first thing to do was test the RGB LED for brightness levels, so I just connected it to the digital output pins of my Arduino-compatible board via suitable current-limiting resistors. To save cost it doesn’t use a backup lithium battery on the real-time clock IC, but you could add one if required. So for the first use you have to wait until about five seconds before midday or midnight, then power it up. It is set to start at 12:00 upon power up. Then the clock will not display anything for around forty seconds, then repeat the process. It reminds me of the giant killer orb “ Rover” from “The Prisoner“… Using a minimal Arduino bootrom system, a DS1307 real time clock IC and an RGB diffused LED, you can make a clock that blinks the time, using the colours of the LED to note different numerical values.įor example, if the time is 12:45, the clock will blink red 12 times, then show blue for a second (think of this as the colon on a digital clock) then blink four times in green (for forty minutes), then blink three times in red for the individual minutes. So to counter this, allow me to introduce you to “Blinky” the one-eyed clock: I’ve always enjoyed making Arduino-powered clocks, however over time they tended to become increasingly complex. You can still make it today, the parts are easily available. Please read the entire article before starting your own. This is a rewrite of a project I created in 2010 which brought me a lot of joy, so I hope you enjoy it too.
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