A clock – yes. You can never have too many clocks. Also, a digital thermometer and an alarm clock. It is based on the Atmel ATmega328 and Arduino IDE, with open-source firmware. The real-time clock uses the DS1307 circuit with battery backup that we know and love. This means you can completely modify the clock or concoct a completely different use for your Simpleclock. Countdown timer? There’s an idea…
Furthemore, the display module is their individual I2C-interface TWI Display. Therefore you have a clock as well as some Arduino-based hardware to experiment with later on. However, let’s assemble it first.
Putting it all together was quite straight-forward. You can follow the detailed instructions at the akafugu site. All the parts required to make a functional clock as advertised are included with the kit:
Here are the brains of the operation – the pre-programmed microcontroller and the DS1307 real-time clock IC:
You do receive an IC socket for the MCU, but not for the RTC – however this shouldn’t be an issue – just double-check your soldering and have some confidence. The PCBs are nicely laid out with solder-masking and a clear silk-screen:
The PCB on the left in the images above is for the display module – it runs an ATtiny microcontroller than can be worked with separately. Moving forward, you start with the lowest-profile components including the resistors and capacitors:
Take note of the vice – these are great, and light years ahead of the “helping hands” things you see around the traps. This was a Stanley model from element14. The resistors sit in nicely:
The next step is to put a blob of solder on the solder pad which will be beneath the backup battery holder – this forces contact between the negative side of the coin cell battery and the PCB:
Everything else went smoothly – I did have a small worry about the pin spacing for the USB power socket, however a clean tip and a steady hand solved that problem:
The rest of the clock board is much easier – just follow the instructions, take your time and relax. Soon enough you’ll be finished:
However I did have one “oops” moment – I left the PTC in too tall, so it needed to be bent over a little to give way for the display module when inserted:
The next task is to solder the four digit display to the display PCB – nothing new here:
Which leaves you with the standalone display module:
Using the Simpleclock
The firmware for clock use as described in the product page is already loaded in the MCU, so you can use it without needing and programming time or effort. It is powered via a mini-USB cable which you will need to acquire yourself.
Frankly the design should have a DC socket and regulator – perhaps for the second revision With second thought, it’s better running from USB. When I turn on the computer in the morning the Simpleclock beeps and ‘wakes up’. The menu system is simple and setting the time and alarm is deceptively so. Some thought has been put into the user interface so once assembled, you could always give the clock away as a gift without fear of being asked for help. However mine is staying on top of the monitor for the office PC:
And here it is in action on the bench:
If you get the urge to modify and update the code, it is easily done. As the Simpleclock kit is open source, all the data required is available from Akafugu’s github page. Please read the notes and other documentation before updating your clock. The easiest way to physically upload the new code will be with a 5V FTDI to USB adaptor or cable.
The Simpleclock was easy to assemble and works very well. It would make a fun kit for those learning to solder, as they have something that once completed is a reminder of their success and useful in daily life. Apart from using USB for power instead of a DC socket – it’s a great kit and I would recommend it to anyone interested in clocks, enjoys kit assembly, or as a gift to a young one to introduce them to electronics and microcontrollers.
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