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A project log for Back To The Future Time Circuit Clock

Back To The Future Time Circuit Clock with clock, alarm and FM radio receiver.

atherosatheros 04/28/2014 at 17:301 Comment

What's new?

We did a lot with bwa since last update. I'm spending a lot of time working on the hardware. I decided to post some pictures.

Those are 7-segment displays for first two rows of the time circuit with the display controller board. Notice the ugly prototype boards driving the displays. It turns out those are very hard to make compared to etching normal PCBs and adding just a few jumper wires. After I made those, I decided it's time to end this prototype madness.

The time was running low, so it was time to speedup and make more PCBs at once. You can see on this photo 2 14-segments display boards and 3 drivers for them.

Routing lots of parallel signals on a single-sided PCB is a nightmare. We tried making double-sided PCBs, but vias and board alignment were very difficult, so all our boards are single-sided. In some eagle files, you'll see wires on top side, in the PCBs we made, they are replaced by normal wires.

Here you can see most of the PCBs we made, most assembled.


Because of time constraints, lack of tools and experience, we've decided to go with a wooden casing. This is a partially cut front panel for one of the rows.

And finally:

This is how it looks. Not too bad!

The radio

I am very disappointed by the Si470x module. We failed to read any RDS from it, might be caused bad reception (I had to pull out a long write from the basement where bwa's workshop is). The main problem is when it is powering up. 9/10 it causes a loud click in the speakers and it reboots the arduino. It looks like power loss of some kind. Large power supplies and capacitors don't help. The strange thing is that it works flawlessly when there is additional power connections from my notebook. I'll have to look into it later.

Other than that, the libraries for arduino don't offer much: seek up / down, set frequency, set volume and read RDS - blocking... I have no idea how to address this issue.

What's next

So I have most of the hardware, some untested and a beginning of the casing. I think it's time to code the Time Circuit Board:

There are chances it might work :)


atheros wrote 04/28/2014 at 18:00 point
Please note that soldering on sparkfun radio module and levelshifter is bad and the board is dirty because we made a mistake in main board schematics and had to turn those boards around.

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