Node Controller Update
Posted by JEC on November 6th, 2009
They say that when calculating time required for a project, you should make your best estimate and double it.
Then add an order of magnitude.
So an hour becomes two days, a week becomes two months, etc.
This adage certainly holds here.
Not much new to mention today, so I’ve included a picture of the prototype controller.
It’s big – 8.12″ x 4.0″. The end user wanted field-replaceable driver chips, so we picked some chunky DIP parts. This board can drive 16 separate strings, and each string can contain 2048 nodes.
The original design had 2 x LM1117 SMD voltage regulators, one each for the +5 and +3v3 rails. But heat dissipation was a problem – nearly 2 W – they were swapped out for a TO-220 package + heat sink. The ethernet controller (Wiznet W5100) is only available in a .3mm pitch, 80-TQFP package. Getting all those leads soldered in only the proper place takes a steady, steady hand.
Rev2 boards are being manufactured right now, and ought to ship on Monday.
Onward!
November 7th, 2009 at 5:33 pm
Its sure been a bigger effort than anticipated, however the learning process in the middle has been worth it.. A brand new processor and code base to learn.. The ability to add ip/ethernet into projects opens a stack of opportunity!
August 19th, 2010 at 4:40 am
Amazing amount of time you have put into this wonderful outcome. Please let me know an update on where you are with this project.
Thank you for your time, and hard work. I hope it pays off for you as I know what it takes to design and build.
Mitch
Please shoot me an email if you would.