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Month: December 2017

Matlab

Matlab

Now this is vacation. Sunshine, swimming, and Matlab!

Up

Up

You can kinda sorta almost pretend you can see the curvature of the earth! Ok perhaps not.. but 49,500 feet is still pretty high up there.

Dev

Dev

On the hardware dev side, I populated most of the parts on the new PCB. I was going to do some more point to point testing, but I figured life is short so I just applied power, flashed in some new firmware I wrote, and waited to see what happened.

I was pleasantly surprised to have no smoke, no fire, and CAN packets jumping off the screen. I made a few small changes in the ADC setup this time, as there is now a dedicated high precision 2.5V reference, as well as a channel for measuring the 5V rail precisely in cases where a ratiometric sensor is used. I also made some improvements to the power supply circuit for better noise filtering. Since this board uses my final form factor (the case and connector), I’ll install this one in a car for some real world testing asap.

Books

Books

Thanks Dad for a most interesting book for my birthday! I’ll read up so I’m prepared for conversation on my next visit home.

I have seen a few reviews of this book, and it does indeed start out with the relatively (ha) basic mathematical foundations and builds up those areas to help understand general relativity. With chapter titles like ‘The Riemann curvature tensor’ it is a page turner for sure!

Filter

Filter

Did I mention how much I love digital filters?

Mess

Mess

Speaking of screwups I made this week, I got my third prototype board back and populated it. [edit for clarity and less funniness]. When I went to put in the small DC-DC converters it turns out I swapped the board layout for those parts with a smaller part, so there really isn’t enough room. After a bit of playing around I was able to mount a few small components on the bottom side and get everything to fit. I thought I had checked out the layout pretty carefully, but I missed this.

I added another step to my pre-board-order validation list that includes double checking the layout and spacing for part size, so a good outcome overall.

On a more successful note, I got a simple ADC and DAC setup connected to Simulink so I can drive the analog inputs of my board with some controlled mixed signals to help with calibration. I love automating stuff like this.

Video

Video

Saturday morning cartoons.. sort of. A great video looking at the Riemann zeta function. 3Blue1Brown videos are excellent introduction to interesting math topic for the average person. 22 mins of really worthwhile time. A warning that you might get sucked into hours of these videos. 😉

https://www.youtube.com/watch?v=sD0NjbwqlYw
https://www.youtube.com/watch?v=sD0NjbwqlYwRiemann

GTR!

GTR!

I like this view.

PCBs

PCBs

My PCBs came back from OSHPark. Looks good for my last through hole prototype. It appears like I didn’t mess up the layout for the connector/case from TE, so that is excellent! The connectors are 12pin DTMs, so something I already use in most of my cars.

I also got some 20 and 31 pin Deustch HDP20 connectors for terminating the sensor cords in the GTR/firewall. I like the HDP20s as they use the same pins as the DTMs (Size 20), and DT (Size 16), and are slightly more cost effective than the AS series.

Time to populate these guys and load up the new firmware
I worked on over the weekend.

OBEELS

OBEELS

I am an engineer. OBEELS can suck it.

http://www.oregonlive.com/portland/index.ssf/2017/12/state_board_concedes_it_violat.html