Eload PC interface

[Harvs]

As I'm sure a few of you will remember, I've been working on some eload projects with STM32 uCs.  I know a few people who were interested in this having, like many on here, built their own purely analog models.  However, pretty much whenever I explained what they need to do to put together a free tool chain for the ARM, everyone basically said words to the effect “it wasn’t for them” (I’m sure most will be able to imagine the more colourful language actually used here.)

Ok fair enough, so I thought it wouldn’t be hard to port the basics across to the ever popular AVR. Well it turned out to be far more of a PITA than I thought, even though they both use GCC, going from a 32bit uC to the 8bit made it a pain to deal with large data types for all the scaling.  Also I’d heavily used the DMA and other functions that the AVR just doesn’t have.  So I pulled all the heavy lifting back to the PC, and have just used the AVR as an interface device to the ADC and DAC, and used its internal EEPROM to store all the calibration values.

Enough about its origins.   It’s going to be an Arduino compatible board with 16bit DAC for current set, and a 16bit ADC for the shunt current and input voltage measurement.  The voltage input will have the ranging circuitry and protection on it.  So it should be trivial to hook into a diy eload project.  I think this has the benefit of people being able to undertake this popular project, and then easily add some serious functionality to it so it’s more than just a toy.

Having completed most of the boring stuff, like the calibration utility, the uC code and the interface library, I’m putting together prototypes for the PC interface.  Attached is one I just threw together last night to plot IV load curves for power supplies.  In this pic it has just run a load test on a recom RBE-0505s isolated PCB mount 5V converter.  I’ve personally wanted this automated capability for a while, because you can uncover all sorts of characteristics about a control loop from that sort of plot.

I’m interested in hearing from anyone that might be interested in using the project, to get input on what sort of functionality would be useful.  Of course, it’s going to be open (hardware and software,) and will be in the sub $20USD mark to build including PCB and parts (without psu as it’s assumed this would already be part of your eload project.)

[Kevin.D]

I remember you where working on an eload project that was built into a  pc case ,  Are you still working on it . ?

[Harvs]

Yeah I am.  But it's taken a different turn.  I'm using parts of that design now in my master thesis project, so I'm not sure how much of it in the end I'll be able to release to the public domain.