Of Microcontrollers and Timekeeping – The Beginning

Clock Fritzing Schematic

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.

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Printed Record Player Lid Hinge

Recently I got a Sony direct drive record player from a garage sale. The previous owner was the original owner, the way he talked about it you could tell he took care of it. The record player works perfectly, except that one of the hinges that holds up the lid was broken. This means that the lid wouldn’t stay up on its own.

Hinge Rapaired

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DIY 3D Printing

My Makerbot Thing-o-maticLately I have been spending most of my time using and upgrading my makerbot thing-o-matic 3d printer. I have been using it to print parts for school projects such as robot chassis (not online yet) and a stereoscopic camera mount (http://www.thingiverse.com/thing:8050).

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.

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Mech Labs logoMechLabs is a site for (mostly) mechatronics-related projects.

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.

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