Because I've never designed a PCB before, I first needed software (free, of course) to do this! After a little research, I figured Eagle CAD was the best to do this as there are extensive libraries available. The one that would be the most useful for me was, and currently is the SparkFun library, as they have the schematic and footprint of many of the parts I needed to use. They even have a special 'locking' footprint that is designed to hold pins in place upside down with friction so you can solder with ease! However, I didn't dare try anything fancy, since this is my first board. Eagle CAD, and the SparkFun library can be downloaded here:
However, the free version of Eagle does have some restrictions. You can't have a schematic that spans multiple pages, and the maximum board size is 100mm x 80mm. Also, you can't have more than 2 layers of copper (no internal layers). Bummer, but a great program nonetheless.
However, the free version of Eagle does have some restrictions. You can't have a schematic that spans multiple pages, and the maximum board size is 100mm x 80mm. Also, you can't have more than 2 layers of copper (no internal layers). Bummer, but a great program nonetheless.
After watching a few videos on YouTube to learn how to design a PCB and schematic in Eagle, I got started! After much work, and FOUR revisions, I got something I was happy with!
Then, I got cracking on placing the components and routing the board (I avoided the autorouter as much as possible, until the very end, where I got bored...). This was by far the hardest and most tedious part of the process! Some of my early designs looked like this (they don't follow the above schematic, that was my final one):
First attempt. Tried to make it as small as possible, but sticking the LCD out like that is just asking for trouble! Hadn't thought of adding the FT232RL yet.
Rev 2. Much better. In fact, I probably would have sent this board to be made, had I not considered surface mount technology (SMT).
Much better! I used the SparkFun library for more of the things here, and added space for a heat sink (for the L298N). Still a few bugs though, especially in the silkscreen. When I moved the USB receptacle out so it sticks out of the board (so the plug will actually fit), I forgot to move the silkscreen outline with it! Also, the text at the bottom would have been covered by the LCD once the board is populated (duh!). I changed most of my extra components (resistors, LEDs, capacitors, etc) to surface mount, mostly of an 0805 (2012 metric) size package. This makes the board look much neater and more professional.
A through-hole board. Yuck!
Actually, it's pretty impressive, but nothing compared to a surface mount board.
A much neater looking board!
I was quite happy with the final design, once the bugs were worked out. "This could be the one", I said to myself!
Anyway, for the newbies trying out Eagle for the first time (I'm probably still in that phase), here are some excellent tutorials:
Jeremy Blum has a couple of nice videos explaining how to use Eagle Cad:
Much better! I used the SparkFun library for more of the things here, and added space for a heat sink (for the L298N). Still a few bugs though, especially in the silkscreen. When I moved the USB receptacle out so it sticks out of the board (so the plug will actually fit), I forgot to move the silkscreen outline with it! Also, the text at the bottom would have been covered by the LCD once the board is populated (duh!). I changed most of my extra components (resistors, LEDs, capacitors, etc) to surface mount, mostly of an 0805 (2012 metric) size package. This makes the board look much neater and more professional.
A through-hole board. Yuck!
Actually, it's pretty impressive, but nothing compared to a surface mount board.
A much neater looking board!
I was quite happy with the final design, once the bugs were worked out. "This could be the one", I said to myself!
Anyway, for the newbies trying out Eagle for the first time (I'm probably still in that phase), here are some excellent tutorials:
Jeremy Blum has a couple of nice videos explaining how to use Eagle Cad:
Part 1 (Schematic Design)
Part 2 (Board Layout)
Also, SparkFun has a nice page on a similar thing, using an FT232RL breakout as an example (Yay!! I needed to know how to wire up the thing and they have a whole tutorial doing it step by step!!!!)
Finally, there's also a 12-part series (no, I'm not going to embed all the videos here) on youtube. Just search up (on YT) "eagle cad lesson", and you should find a series by a user called rpcelectronics.
-nanohex
-nanohex
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