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Topic: Allduino (bluetooth, lipo battery+charger, ATMEGA328P, FTDI) Eagle Design (Read 3 times) previous topic - next topic

zeroplus

Hi all,

I have this rather ambitious first project in the works (ambitions for a person of my more modest skill level at least).  I was hoping to get some opinions on my design in Eagle.  I might find this to be a huge mistake in the future but I tried to do the whole thing in one go instead of coming here and asking for each and every part of it first.  Instead I have what I hope is a final product and this is what it is:


  • 3.3V regulated by ultra-low dropout LDO

  • ATMEGA328P at 8MHz

  • LiPo powered

  • Battery charging IC from USB (MAX1811)

  • Micro-USB

  • FTDI USB->UART

  • HC-05 bluetooth Serial Port Profile module (from ebay)

  • Really small PCB size (~50mm x ~20mm)

  • Low profile ~7mm? (eyeballing it; height of microusb + height of ftdi + PCB thickness)



I attached the Eagle files and the Gerbers in the zip file (in case someone who wants to look at it doesn't use Eagle).  In addition, I have already had it fabbed by SeeedStudio's Fusion PCB service (which is awesomely cheap I must say; for someone just starting out it's nice to not burn a hole in my pocket only to find out later that this kinda thing isn't for me).  I have every part I need except the 10uF caps right now and have populated everything I could.  So far the power rail seems to be working well but without the caps I dare not go any further for now.

What I'm looking for are any mistakes I may have made, improvements I can make (on my Eagle design, software suggestions, bluetooth device ideas, etc).  I have extra boards in case someone decides they want one.  They come with 2 panelized on a 50x50mm board one with ground planes and the other without.  The BOM is not particularly cheap but since this is for a University project I managed to get the majority of important components on sample orders.

Lastly, this is one of my few experiences on a forum and my first on this one in particular so feel free to take a shot at me if this post is in the wrong place.

PS. I am open to making this a commercial thing if ever it comes to that.

Lemme know how I did with this first project of it's kind for me.

Edit: I should also note that this is a 3.3V LDO version.  I am in the process of replacing the (rather large) LDO for a switching power supply to bring it to a 5V rail.

zeroplus

Here are some pictures

Fat D

Cool thing, but forcibly tying the BT module to a software serial means it cannot be moved to the hardware serial for cool stuff like wireless programming and such.

zeroplus

Yea I remembering pondering that for a ver long time. I opted to go for a tethered solution first and I could later tie those two together. I just lose the use of two pins is all.  My project requires two uarts and I did not want to bump it to a mega IC..

Other than that, i bet I could use this as  a peripheral prototyping board for android or windows 8 or something.

I have like 8 spare boards with two boards per board lol. Need some use cases.

Edit: moment of clarity! I remember worrying about the FTDI and the bluetooth in conjunction with another load sinking too much current on the pin and becoming indeterminate.  Perhaps Im paranoid.

pito

..btw - are you using 2.5mm pitch? That is not 0.1" however..

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