I made a schematic with an ATmega328, a LT1763, and a HC-05 module. I was wondering if I made any mistakes on the schematic. It also has a 4 pin female header for a MPU-6050 module. It might end up being a mini quadcopter someday, but for now I made the schematic as a first step and to learn more about better circuit design. Here is my circuit, you can click for a larger view:


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    \$\begingroup\$ Just a point of style: God gave us corners for a reason. \$\endgroup\$
    – Majenko
    Commented Dec 23, 2014 at 0:36
  • \$\begingroup\$ When viewing this with a right-click View Image, this appears (at least in FireFox) to have two sizes: unreadable and huge (too big to read). \$\endgroup\$
    – tcrosley
    Commented Dec 23, 2014 at 0:53
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    \$\begingroup\$ Suggestion: try to avoid diagonal lines in schematics as much as possible. | Try to have ground connections at bottom of subdiagrams - eg R12 + LED3. \$\endgroup\$
    – Russell McMahon
    Commented Dec 23, 2014 at 0:55
  • \$\begingroup\$ @tcrosley - Put the native size to the "unreadable" in the browser's view image window. Then use your mouse wheel to zoom the window till it is readable. Not ideal but works pretty good. \$\endgroup\$ Commented Dec 23, 2014 at 0:57
  • \$\begingroup\$ @RussellMcMahon I fixed the schematic a bit \$\endgroup\$
    – user33335
    Commented Dec 23, 2014 at 1:01

1 Answer 1


Looks good at a quick look through. Nothing obviously bad.

BSS138 are especially wimpy MOSFETS. Ok for playing but do not do justice to the rest of the circuit. Not up to quad copter use, but, you know that.

DTR is intended to reset the processor I assume.

To pass the Olin schematic test you'd want (amongst other things)

  • To move text strings off lines (eg PS3 PS4 by MOSFETs and rotate them to horizontal where sensibly possible. PWM3 label is overwritten by MOSFET name etc. VCC label in eg FTDI box turn 90 degrees.

  • Have connectors from FETs vertically above FETs rather than bent at 90 degrees. Vbatt could be above or to one side.

  • And similar

Aim is to not 'twist brain' to follow obvious flow.

Some people will read diagrams with small points as above and find them less than comfortable but bearable. Others will essentially refuse to look at them. The latter reaction is somewhat extreme but reflects an underlying semi-reality - a really tidy diagram with attention to layout, text and component orientation, consistent labelling and more SUGGESTS an underlying technical competence, and a messy diagram tends to suggest the onbious. Neither of these impressions may be correct, but they are often a useful starting guide. Also, arguably, a tidy diagram reflects respect for those who you expect to use it (and the validity and relevance this has been argued at length :-) ) and is more likely to allow you to spot technical errors.

NB: DO NOT ever take my diagrams as examples of how to do things well. I am a "classic messy" who attempts to force the world's mold on my output with varying success. Judgements based on normal standards may mislead one wrt the value of a classic messy's offerings - and may not :-). Equally a chronic super-tidy (who can in their own way be just as bad as a messy) may produce superb copy but not always match it with underlying competence. FWIW.

  • \$\begingroup\$ Thank you for this detailed answer, I wasn't going to use the BSS138 MOSFETS, I was just using that package since it was the correct size for the actual mosfets. Thank you for the tips, they helped a lot. \$\endgroup\$
    – user33335
    Commented Dec 23, 2014 at 20:55

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