Tutorial on driving real time clocks with Arduino

tronixstuff have written a great tutorial how to interface and program real time clocks (RTC). As an example he took two widely used chips DS1307 and DS3231. The main difference between both modules is clocking mechanism that can result in precision. Usually they come in modules that can be easily connected to microcontroller board via I2C interface. Both modules come with built in pull-up resistor, so there are only two wires required to interface to microcontroller (plus power lines). Simple demo program allows to output time and date infromation to serial terminal window every seconds. Both modules come with backup batteries so if you diconnect them from Arduino board they will continue counting time. When next time you connect them again, you will get correct time values. Continue reading

Simple OLED alarm clock with temperature feature

OLED displays have many benefits over regular LCDs. They have better better contrast. Because there are not back-light used, a deep black levels can be displayed. They have wider viewing angles and are more power efficient. Also are more lightweight what makes them attractive for using in hand-held devices. OLED displays are available in hobby market so everyone can use them for great projects and see the benefits. Df99 have shared his instructable where he builds pretty cool alarm clock with temperature display by using Arduino Micro and 128×64 OLED display based on SSD1306 controller. Clock function is implemented with DS3231 RTC IC which has Arduino library support. Clock has two push-buttons for clock setting. Temperature readings are done from RTC chip where sensor is used to compensate temperature drift. Continue reading

Outstanding steampunkish VFD wristwatch

Wristwatch projects are coll for many reasons. First of all how they are built – components need to be squeezed to make watch wearable. Another thing is display. What different types of displays can be used. LCDs and LEDs seems to be getting boring, unless they are used in some weird way. Other things also are important like overall look, power supply , features and controls. Johnengineer has been working on steampunk wristwatch for couple months and he came up with something awesome. The unique idea was to use IVL2-7/5 VFD display. They are relatively small to fit on a watch and pulls out relatively small amount of current. It also requires low grid voltage (~12V). Display is transparent, so background PCB is visible and this can be considered a cool design feature. Clock is ticking around Atmega88 microcontroller along with RTC DS3231. Display is driven by dedicated MAX6920 12-bit shift register. Since watch is powered from single AA battery, there are couple boost converters – one for generating 5V to power electronics and another 13.5V to power VFD grid.… Continue reading