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Umm Rev3 :D

A project log for Digital Speedometer

A new digital dash to replace the slow inaccurate one on my cheap Chinese bike

mangus-tiranusMangus Tiranus 10/22/2016 at 19:260 Comments

Sooooooooooooo. Rev 2 had so much promise, but after getting it working I quickly discovered it had some serious issues with power distribution.

So I had to redesign the board and give more thought to the power lanes.

I now have 5v regs dedicated for each of the led arrays and a third 5v reg for the rest of the project.

Because I need a stable regulated 12v to run the backlights and run the fuel sender probe, a friend recommended that i remove the 12v regulator I had because it would be better to use a boost converter from the third 5v supply.

Its a stop gap measure that might change in a later version. But this does solve some issues with the widely ranging 12v line off the bike.

The old 12v reg I was using needed a 2volt + headroom to get a stable 12v. The other option I had was to use a low drop 12v reg. I found one, but they're expensive.

And its also possible that the bikes voltage could end up dropping bellow 12.5v... (the bikes voltage/rectifier is on the blink i think, I will fix that, but it does highlight a possible real world issue the dash has to contend with.

I would like to make this a product I can sell, so while I'm learning how to build it, its good to find these issues and work out how to fix them.

Anyway, I've etched the board and got a solder mask on both sides. I might even put on a silk :D Who knows...

Anyway tomorrow ill be reflowing the SMD bits. Ill post a pic then.

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