Turn-key PCB assembly services in prototype quantities or low-volume to mid-volume production runs

Movable Alarm Clock

This project is for the people who faces difficulty in waking up early in the morning or have the habit of snoozing the alarm. In short, this alarm clock runs away from the user as he tries to snooze his alarm. The whole unit is mounted on a chassis with caterpillar-style wheels driven by two small DC motors. The runaway feature is implemented using a proximity sensor which is placed near the snooze button. It has all the features of a “regular” alarm clock: settable time and alarm, snooze, and alarm on/off. The project is divided into four levels namely the clock feature with display. The alarm feature motion control and proximity detection. The alarm tone is generated using a 555 timer while a real timer kernel is implemented on the Atmega MCU to run each of these tasks independently and simultaneously on the microcontroller. The display is built out of seven segment LED’s running on the principle of persistence of vision. The accuracy of the clock is pretty good, and the speed of the bot can be raised up… Continue reading

DIY hard disk based desktop Clock

It’s not an ordinary desktop clock. It’s actually made out of a computer hard disk. Yes, a computer hard disk that the project maker found years back in a non-working condition and decided to turn it into a clock. It’s powered by an atmega controller. The hard disk indicates the hour while the read/write head serves as the “minute” indicator by moving from the outer to the inner edge of the disk. For every hour passed, the stepper motor emits a humming sound indicating that an hour has past. The microcontroller, stepper motor driver and some transistors for amplifying the signals sent by a set light sensors that is hidden under the disk and measures its position.  A driver is used since hard disk motor because that pulls a lot of current due to the weight of the disk. Another good thing about it is it has a demo mode. This makes one minute of internal time pass in 2 seconds real time so that you can easily watch the thing working. The clock is in excellent working condition till… Continue reading


If you have followed some previous reviews, you might have found that it had a review of a wrist-watch that was just totally amazing. This one you can say is an advanced version of it and was built in a span of 6 months. It works on the principle of persistence of vision which is the same technique used in videos, multiplexing of displays and even in CRT Tv and also analog oscilloscope. The clock used persistence of vision to “draw” an image from individual pulses of light.  These pulses of light occur so fast that our eyes cannot distinguish them individually and they become an image. It features a ATMEGA168 controller which is run on 8MHZ internal oscillator leaving the external crystal free to handle the time keeping. The motor that drives the CD is actually taken from a CD-ROM and the speed is controlled by PWM signals which is the easiest way to generate any analog voltage. To measure the rotational speed and provide an index for the display, I used an IR photodiode and phototransistor which detects… Continue reading

Interrupt driven time keeper using ATTtiny2313

What is a clock? It’s a time keeping entity that increments at a constant rate. Szymon Dyja demonstrated how to keep the time using built in counters of the ATTtiny2313. Szymon’s simple design uses a 16×2 LCD with backlight and has an accuracy of 1 second / 48 hours. The 16 bit counter of the AVR is set to overflow when a second had lapsed, how to do this? Since the project uses an 8MHz crystal the counter is incremented every 8MHz/1024 and thus since the counter is 16 bit it will overflow at ((2 ^ 16-1) – (8000000/1024)) = 57822.5 which corresponds to a second. When the 16 bit counters over flow an interrupt is asserted, this assertion signals that the specific time span had lapsed and that global time variable needs to be updated which will also trigger the LCD update routines. Entire project can be downloaded here. The next step would be to add a synchronizing function to the clock to correct any inconsistencies. Time through Ethernet? Continue reading

Clocks can be fun

There are many digital clock projects in the internet. Each of them has something different that makes them interesting and attractive. This one has some charm too. It is very simple clock without any buttons and alarms, but it has an IR light detector. Microcontroller simply reads IR sensor data and depending on hand distance from clock MCU increases or decreases LCD backlight. So, by hovering hand near clock you can see time. The closer hand to clock– the brighter LCD. Accurate time is calculated by separate RTC DS3232 IC. Continue reading