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Does anyone know how many pins on a Panda?


#1

I do !

Attached is an image of my Easter project.

There are 78 pins, excluding the JTAG header, on a Panda. That includes all the power/GND pins and the UEXT header.

There are also 40 pins on a WIZ812 ethernet module. There’s 8 pins on an 24LC256 eeprom. There’s 3 pins on a DS18B20 one-wire temperature sensor. There’s 3 pins as a OW header, and 4 pins for a serial port daughter board header. There are also 16 holes for jumper wires (this is a single sided board). That’s a total of 152.

On the (not-pictured) serial daughterboard, there are a total of 46 pins, including a MAX232 in DIP16, a DB9 connector, 5 capacitors and other jumper wires.

There are also 50 pins unpopulated on a standard Panda board, again excluding JTAG.

So, this weekend I drilled 152 + 46 = 198 holes using 0.8mm drills - of which I broke two and blunted two more. I then drilled 198 holes with a 1.0mm drill to make them big enough for my component legs (yes, that’s one thing I would have done differently in hindsight, 1.0mm straight away :slight_smile: ). I then soldered 198 connections on the two boards, plus the 50 pins on my Panda to fully populate it. I then re-soldered several of these when I figured out I used the wrong DB9 connector and when I found a few not-complete solder joints.

I then modified the board to take an additional 4-pin terminal screw block that came about through scope creep (which I’m a bit bummed about - means the board isn’t as neat as it could have been !).

But now it’s over to software time to make sure things work as expected - so far so good, but I’ve only checked the scope-creep connectors, not the ethernet / SD card / RS232 / I2C eeprom.

Reflections on the whole thing. The reason I didn’t outsource this to Laen / DorkbotPDX or similar was that this was always only going to be a once-off project. I couldn’t see any reason to “waste” two other boards that I had to have made by Laen’s process. In hindsight, there is a LOT of drilling on this board. I should have just had it made and be done with it. It’s rewarding and all to have made it from scratch, but the economics of it all are not fantastic, I used a sheet of Press-n-peel (say $1), I used say $4 of PCB board, I used ~1/3 of a container of $10 Aluminium Persulphate etchant (say $3), I broke two 0.8mm drills (say $1), so that’s about $10 all up. I probably spent the better part of 8 hours doing things I wouldn’t have to do if I bought the board (drilling etc). Sure, I didn’t need to worry about a lot of things on my board design (solder masking, silkscreen etc) but on the whole, that would have been a much better use of my time and money than how I did it. But I’ve done it now and I have seen the pitfalls, and now I know better :slight_smile:


#2

Crazy. You should have done a time-lapse video.


#3

Wow! What’s it going to be used for?


#4

@ Ian, it’s going into my garage. It’s going to connect to my Solar Panel inverter and upload data to the PVOutput.org website (simple HTTP PUT) and will replace a netbook doing this at the moment. It’ll also be a node in the “home network”, with the SD card storing web site info and data from the panels. And since the scope was increased and catered for, it’ll also have open and closed sensors for the garage door and possibly an open/closed control to the door motor, which might then be web-enabled.


#5

Um. Please don’t “web-enable” the motor to your garage door opener, unless you don’t mind having your stuff stolen. Also be careful about the sort of stuff you publish online about your house. Average power in and out, good. Time charts that bad guys can use to figure out what times of day you’re likely to be away from home, bad.


#6

Yes, agreed, I am pretty good with understanding the boundaries of what is good and bad practices there :wink: I’ll make sure the things that are “enabled” are appropriate and appropriately controlled.


#7

Nice board!