Hey
I am working on a school project. My group are trying to develope a solar catching sensor, runned with arduino.
We are trying to create a PCB containing the atmega 328 microcontroller.
By using external LDR, servos (9G motor) and IC2 bus.
It is my first time designing a PCB, so any advised if I should change anything I highly appreciated 
Youre missing the decoupling caps for the atmega328
Why is AREF tied to VCC?
be07128902:
Like this?
No. One capacitor per VCC / GND pair.
I dont need to apply 5V to AREF to get correct reading at the analog ports?
be07128902:
Inserted another capacitor now. Do I use the correct size?
I will happily respond after you embed the image in your post. To see how it's done simply edit one of your previous posts.
I dont need to apply 5V to AREF to get correct reading at the analog ports?
No. When you're using Vcc as AREF, they are connected internally, and it doesn't need to be connected to 5V. If you use the internal 1.1V Vref, you'll end up connecting Vcc to 1.1V internally, which is bad. Unless you have an actual external reference voltage other than Vcca, AREF should only have the cap to ground (which is missing in your schematic.)
(This is a FREQUENT error in published AVR schematics.)
Unless you're going for the absolute minimum space:
You have a separate voltage regulator for your servos, which is good. Is a 340T big enough to power both servos simultaneously? (you have a 2A input, and two 1A regulators, right? One of which only powers the 328p?) Did you want to set the servo regulator to 6V instead of 5V (there are a couple of easy ways to do that.)
Are the pullup resistors for your LDRs really supposed to be 220 ohms? It seems low.
Why not build a PCB shield that fits on your Arduino - simplier
be07128902:
Inserted another capacitor now. Do I use the correct size?
westfw:
Unless you're going for the absolute minimum space:
- An ISP connector would be a good thing.
- A "pin13" LED is useful for debugging.
- As is a serial port.
- It wouldn't be a bad thing to provide off-board connectors for all of your un-used pins.
You have a separate voltage regulator for your servos, which is good. Is a 340T big enough to power both servos simultaneously? (you have a 2A input, and two 1A regulators, right? One of which only powers the 328p?) Did you want to set the servo regulator to 6V instead of 5V (there are a couple of easy ways to do that.)
Are the pullup resistors for your LDRs really supposed to be 220 ohms? It seems low.
I am supposed to keep it into a minimal, according to the description of the the product.
Thanks for notifying me on the LDR resistances, I havent decided what LDR to use yet, but think the resistors will be 100K.
THe servos are tower 9g, and I have read that they use approx 500mA, so think it will be OK.
The 340T should be good for 1A or something. Dont know if I can use 6V for the servos, documentation says 4.8-5V.
@Hammy: We are supposed to create a product with as minimal as possible, just to do the task it is mean to do.
Thanks for all replies
@Coding Badly : I have been trying to edit my posts to include the image embed but, that one post wont change. : /
be07128902:
@Hammy: We are supposed to create a product with as minimal as possible, just to do the task it is mean to do.
Than leave out any microcontroller. You will find solar tracking experiments just with some motors and two solar panels.
noiasca:
Than leave out any microcontroller. You will find solar tracking experiments just with some motors and two solar panels.
The product is supposed to transmit x and y-axis cordinates to other slave units through the i2c bus. We thought its easier to achieve theese events and transmits with atmega.
