Author Topic: critique my board design  (Read 1974 times)

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Offline jmctechTopic starter

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critique my board design
« on: January 21, 2015, 03:19:22 am »
I am designing a control board for a kids power wheel ride on. I am using an ATMEG328P as the microcontroller. It is going to interface with a 2.4 ghz RC receiver. It will give a parent of a disabled child the ability to control the vehicle or with the flip of a switch on the remote the child will be able to drive it. I am relatively new to the board design. I have put in flyback diodes where the relays for direction and throttle are going to plug into the board. Any input will be greatly appreciated.

 
 

Offline generic_username

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Re: critique my board design
« Reply #1 on: January 21, 2015, 09:19:09 am »
Just my 2 cents

Board looks ok, Only thing I can see atm is: you can certainly shorten some circuit paths as some of them seem kinda long, the think line from Gas Ped to Receiver has a 90° angle which is totally fine but doesn't match the rest of your 45° angles. And lastly you could if you need the space make the board smaller as there's not on it part wise.

cheers.
I always need 3 attempts to plug in a USB connector
 

Offline void_error

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Re: critique my board design
« Reply #2 on: January 21, 2015, 09:50:55 am »
You can easily make that half its current size...
Trust me, I'm NOT an engineer.
 

Offline okaresz

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Re: critique my board design
« Reply #3 on: January 21, 2015, 05:44:32 pm »
I suggest wider clearance between your ground plane and the other traces. Especially around the TH pads. With this small gap around the pads on a poor quality / home manufactured PCB, chances are you will create some shorts when soldering.
And also around screw holes.
 

Offline ajb

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Re: critique my board design
« Reply #4 on: January 21, 2015, 06:28:55 pm »
- Your reset network is wrong.  ATMegas need a resistor pulling reset up to Vcc, and optionally a cap from reset to ground. 
- You need decoupling at the MCU.  100nF or so, one at each Vcc pin, as close as possible. 
- D7 could be problematic.  Vcc is connected to the ISP header so that the programmer can detect the target MCU's operating voltage and set its IO levels (it may actually power the target side of the IO level shifters in some programmers--not sure).  D7 will prevent that, so will prevent at least Atmel's tools from entering programming mode.  Third party tools may not care, especially cheap ones.  If your programmer will be supplying target power while programming, then D7 is fine. 
- How much current are you planning to switch with those transistors?
-Your ground plane is pretty carved up.  Consider spreading the legs of your diodes to allow the ground plane to flow more freely.  Also consider orienting the diodes (and maybe some wire links) vertically and preferentially route traces horizontally (or vice versa) to provide a more contiguous ground pour.
 

Offline ajb

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Re: critique my board design
« Reply #5 on: January 21, 2015, 06:36:15 pm »
You have a connector labeled "steer_pot", as in potentiometer?  If so you probably want to route that to one of the ADC channels on Port C.
 

Offline jmctechTopic starter

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Re: critique my board design
« Reply #6 on: January 23, 2015, 01:00:49 am »
Thank you for all the help, I am making some changes based on your replies. I do have a question though, if  was to go with solid state relays over standard relays would I still need flybacks in place?
 


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