One problem I’ve come across a couple of times is trying get a microcontroller to keep accurate time. In the past I’ve managed to get an ATMEGA168P with an external 16MHz (same as Arduino) to be accurate to within about 5 minutes over a month.

Lately, I’ve been working on a clock where the digits will be separated except for 3 wires connecting them; 2 for power and one for serial communication to the next digit. The master module will keep time and display the first digit then transmit the remaining digits over serial to the next module. That module displays the first digit received and passes the rest along to the next module and the process continues until there are no more modules to receive data. This way the clock is modular, and you only display the number of digits you want to.

Being a clock, I need  to get it to keep accurate time. This time I wanted to go the step further to make it more accurate by using a RTC (real time clock), I chose the DS3232S# by Maxim. The RTC is only included in the master module because the slave modules don’t actually keep time, they only display what they are told to. The module should keep accurate enough time that any variance won’t matter. As well, the RTC has a battery backup that keeps time when the power goes out.

I designed the circuit in Fritzing, a free simple to use software. It’s not as powerful as other software such as Eagle or KI CAD, but I find it easy to design new footprints because you can use Inkscape (free vector drawing software). This circuit does push the software to close to its limits though.

The First prototype design is seen in the picture above. I designed all of the modules as a single circuit board that can later be separated, this will hopefully make assembly easier.

I’ll be posting again when I get the finished board and have time to assemble and test it. I am also still working on designing the mechanical modules that will display the time. I have made a first prototype, but some parts didn’t work as planned. Apparently, laser cut acrylic binds easily if you try to make prismatic joints using two screws that slide in a slot.

I started by measuring what was left of the old hinge as well as the remaining whole hinge and making a model in UGS NX6. Since it was easy to take the hinge apart (Sony actually used to make things to be repaired!) I just needed to replace the one part.

I managed to get the model and print right on the first try (this is a rare thing) then I replaced the broken part, assembled it and re-attached the lid.

After the lid was back on, I plugged everything in and it works beautifully.

Also, that is a beta player under the record player in the first image. I also got that from a garage sale and fixed it.

I have also been designing and printing things because I wanted to see if I could. Most of those can be seen here: http://www.thingiverse.com/J_Hodgie/things.

I have also been printing some upgrades for the printer because I want the quality as high as possible so it can print parts as small and reliably  as possible. The upgrades I have installed are printing some gears and changing the dc motor to a stepper motor. I also designed a tool holder for my commonly used tools and upgraded the automated build platform belt from plastic to titanium.

As I am writing this my extruder is also in a few pieces as I am upgrading to a dual extruder setup so I print with PVA supports and soft PLA as integrated hinges.

Overall, DIY 3D printers allow me to cheaply create whatever part I need, so it is very handy to have around if you can maintain one.

The projects will range from quick projects that (should) be able to finished over a single weekend from conception to completion to longer projects that could take upwards of a month (anything linger than that is unlikely). I will also periodically post some short tutorials on how I get a single part working as a stepping stone to a larger project.

To see some previous projects visit http://www.instructables.com/member/J_Hodgie/. Lately I have been posting my projects to thingiverse (http://www.thingiverse.com/J_Hodgie).

To find more about me and why I build robots check out the about page above.