Hammerhead

Design Document  (Posted for the contest, soon to be revised)

https://www.dropbox.com/s/2q579v7lte86vgt/HammerheadDesignDoc.pdf

Video

Detailed schematic can be found in the Github repository for the hardware.

After sitting on the completed design and giving it a lot of thought I decided I'm going to make a change. The goal of hammerhead is to be a research tool with applications in many areas. I have decided to galvanically isolate the MAX11300 section from the rest of the board. This allows the hammerhead to be of use in applications where isolation is important, an example would be bio-medical engineering projects that require interaction with humans. 

The isolation is being performed by an Linear Technology LTM2883 module. The LTM2883 provideds isolation for the SPI bus interfacting the LPC4337JBD144 with the MAX11300. Also the LTM2883 provides isolation for the power supply of the entire MAX11300 circuit. The design document will be revised when soon when the hardware has been changed to support the new isolation topology.

This afternoon I finished routing the remaining traces of the hammerhead. You can compare the picture in this post with the last one to see how much has been done. The next step for hardware is to make a comprehensive bill of materials (which will be posted here) and perform some cost analysis. I have found in my experience with personal projects in the past that if you don't make a BOM and assess your costs before ordering any parts you will most likely go over budget, since this is a rather expensive design with expensive high end parts I want to be very thorough in the planning stages before purchasing anything. When the BOM is completed I will tweak the hardware design for costs, this is usually how I do my boards, I start with a schematic that goes through several revisions then I take  a first pass at the PCB, after the first PCB I tweak it a lot before readying it for fabrication. Since this board is a cousin/derivative of the first two unmade Mako DSP designs and the AHD there shouldn't be much tweaking, a lot was learned with the other boards. 

Finished first Rev:

Three Dimensional representation:

The last update was about how I changed the design of the powersupply, that was the last major change to the schematic other than some pin swapping here and there to make the routing smoother. Since the last update I have been working on turning the schematic into a PCB. A picture of the PCB as of 7.21.14 has been added to the project pictures to give a good idea of where I'm going with the design. The PCB has been going very fast and should be finished in a day or by the next post. 

On another note I received my MAX11300 PMOD kit from Maxim Integrated in the mail. With this PMOD and the NXP LPC4330 Xplorer dev board I have I will be able to start working on the firmware and top level software for the hammerhead. The plan is to dev almost if not all of the software dev with the MAX11300 wired to the LPC4330 board on a breadboard. The programming jig will also function as prototype of the hammerhead before the PCB is ordered, this will allow me to test a number of things and fix bugs in the PCB before I order it.

Today I changed the power supply. I decided the STM 5VDC LDOs and my NXP 3.3v LDO were too large to hit the size I want for the PCB so I found new regulators and changed the circuit. Using Ti TPS79650DRBT for 5VDC and AVDD, and a Ti TPS73733QDRBRQ1 for the DVDD rail (3.3v). Expect updates to the git repo later this evening!

This first post is to announce the submission of my Hammerhead dev board project to the Hackaday Prize. With the posting of the project page I included the schematics and early stages of the PCB as well as a PDF on github, have a look, there is more to come!