Thursday, December 19, 2013

CryoBUG Rev 2 Controller Boards on Order

The printed circuit boards got ordered from ExpressPCB a couple of days ago, and should be here by tomorrow. I went for the Mini-Board special, which gives you three 2.5"x3.8" boards for as little as $51. However I went for the enhanced version, which includes the soldermask and silkscreen, giving it that production quality look.
(Click on Image to Enlarge)

This time around I was able to go with a smaller transformer, which along with a reduced component count (thanks to the ECIO-28 micro-controller), allowed for the smaller sized board while still retaining the dual voltage aspect (115/230 VAC).

I had some left over I/O on the ECIO-28, so I squeezed in an expansion port (J4), which has an LCD ready pin-out for an optional display.

I am rather pleased with the design, and its compact size.

(Click on Image to Enlarge)
As can be seen in the schematic, the design is very simple compared to the previous version. This of course is due to the micro-controller taking over much of what was done with discrete circuitry, and moving the complexity over to the firmware.

As I mentioned in my previous post, the firmware development is being done with Matrix Multimedia's FlowCode product, which greatly reduces the effort of writing the code and programming the chip.

Since the ECIO-28P has a built-in USB connector and a boot-loader, it is a one button operation within FlowCode to transfer the code to the actual hardware. So writing, testing, and updating firmware is actually a fun process.

As I mentioned earlier, there is also an expansion connector as part of my design suitable for connecting an LCD display (or an OLED, VFD). Although I wont be using the display aspect on my current project, I thought it might be nice to have the flexibility to do so down the road.

Since LCD back lights require a fair amount of power, a VFD or OLED display might be more within the power range of my controller board. So just for fun, I placed an order for a small OLED 8x2 character display from CrystalFontz to see how that might look.

Possible uses could be for an operational status display, or a way to display how many faults, and of what type had occurred. I'm sure it'll be fun playing around with this to see what I can come up with.

Can't wait until tomorrow!

Update 12/22/13: Tomorrow has come and gone. The boards I got back were of excellent quality. The problem is I made a few mistakes, that when all added up were far too many to live with. First problem was that the hole size for the machine pin socket for the ECIO-28P, was simply too tight. Then I noticed that the expansion connector for the external display was flipped right-to-left from what was needed. And then to top it off, I was tied into the wrong four data lines for the display (D0-D3 instead of D4-D7 as it was suppose to be). This is what happens when I skip bread boarding every single aspect, and rush the design out to get made. Anyway I have corrected all the problems and ordered a 2nd set of boards. Also the schematic and PCB layout shown in this post have been updated to reflect these changes (Rev 2.1).


Jonathan Edelson said...

Take a look at OSH Park/Dorkbot PDX for inexpensive high quality circuit boards.

They target 'Makers' and are more suited to small boards. The cost is $5 per square inch of design, for 3 copies of double sided board with silkscreen and solder mask.

Michael St. Pierre said...

Hi Jonathan. Can they work with Express files?

Jonathan Edelson said...

Unfortunately no. ExpressPCB gives away their design software but saves files in a proprietary format that only they can build.

If you can export (or convert) to the generic 'gerber' format, then that can be run by any board house.

One of the cheap versions of 'Eagle Cad' might be suitable for the small boards that you are designing.

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