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5 posts total
Andrew Zonenberg

Boost for reach: Looking for a UI/UX designer for paid work on a F/OSS project.

The fundamental goal is to improve the new user experience for ngscopeclient (ngscopeclient.org/)

I'm not looking for coding/implementation work specifically, more of general human-factors etc feedback on how to make the UI easier to figure out and as intuitive as possible. It's a complex tool with a large feature set and striking a balance between seas of menus and toolbars blocking your view of the data, and making the UI impossible to navigate, is not trivial.

Experience with electronic test and measurement, scientific computing, DSP, or data visualization is a plus.

If you're willing to offer discounted rates for open source projects that's a bonus.

Boost for reach: Looking for a UI/UX designer for paid work on a F/OSS project.

The fundamental goal is to improve the new user experience for ngscopeclient (ngscopeclient.org/)

I'm not looking for coding/implementation work specifically, more of general human-factors etc feedback on how to make the UI easier to figure out and as intuitive as possible. It's a complex tool with a large feature set and striking a balance between seas of menus and toolbars blocking your view of the data,...

Screenshot of a complex software user interface showing various types of graphs, waveform views, and tables of data
A different view showing a graph editor and several 2D density plots of various types
23 August at 16:39 | Open on ioc.exchange
Andrew Zonenberg

New revision IBC board came in!

This design switches from a buck topology to a charge pump and should cut about 2.5W off the idle power consumption, greatly improving low load efficiency.

It also switches from a 2 layer board to 4, helping it shrink the PCB size by about 40% vs the previous design.

Probably won't have time to assemble tonight since I'm still doing firmware for the interface test board.

Bare blue PCB densely covered in gold plated component footprints. Just to the right is a second board covered in solder from factory testing of the board finish. To the top, a cross section potted in resin can be seen.
23 July at 21:47 | Open on ioc.exchange
Andrew Zonenberg

There are three main types of stroopwafels.

Igneous, the most common, are formed by melting a sticky filling and pouring it between two waffles.

Sedimentary stroopwafels are commonly encountered at the bottom of a large container of igneous stroopwafels.

The rarest form is the metamorphic stroopwafel, formed by subjecting igneous and/or sedimentary stroopwafels to extremes of heat and pressure until they fuse together.

A resolidified mass of mini stroopwafels, welded together by melted caramel filling
29 Sep 2023 at 0:39 | Open on ioc.exchange
Andrew Zonenberg

After some ngscopeclient updates and a busy week at work, back to playing with the LTC3374 test board.

Here's channel 1, with back side bulk cap and no high freq cap.. Input ripple ranges from 38 mV p-p / 1.4 mV RMS at no load to 57 mV p-p / 2.5 mV RMS at max design load of 1A.

Output ripple is *slightly* dependent on load, but much less of a shift. Pretty consistent around 21 mV P-P. / 5 mV RMS.

Now let's see what happens when we run the same filter graph on the other supplies.

Screenshot of ngscopeclient showing input and output ripple vs current.
Screenshot of ngscopeclient showing ripple waveforms
19 Mar 2023 at 2:11 | Open on ioc.exchange
Andrew Zonenberg

Channel 2, bulk cap on back side plus high freq cap on the front. No changes to the output side.

Input ripple is greatly improved, ranging from 21 mV p-p / 0.86 mV RMS to 33 mV p-p / 1.7 mV RMS.

Output ripple is only slightly improved, hovering around 19 mV p-p / 4.65 mV RMS regardless of load.

So the high freq cap had a massive impact on input ripple, but fairly small improvement on the output side.

Screenshot of ngscopeclient showing performance of power supply. See text for discussion.
19 Mar 2023 at 2:20 | Open on ioc.exchange
Andrew Zonenberg

First ESP32-PICO-V3 cross section has a few artifacts, but I have more epoxy to use up and I want to get better at making really nice looking cross sections anyway. So I might do another. I have a few extra chips and tow more packs of epoxy to use up.

First off, I probably should have read the datasheet. It's not just the ESP32 and flash chip, there's a 40 MHz crystal and some matching components too. So it's a full SiP with embedded passives on a four layer substrate! This is a lot more interesting to look at than just a single die, which is good.

Less good: the die is way off center in the package. This is fine if you're expecting it, but I ended up sanding into the die using coarse sandpaper during the early stage of the cross section and creating some cracks which are difficult to get rid of. Lesson learned, I'll be prepared next time.

First ESP32-PICO-V3 cross section has a few artifacts, but I have more epoxy to use up and I want to get better at making really nice looking cross sections anyway. So I might do another. I have a few extra chips and tow more packs of epoxy to use up.

First off, I probably should have read the datasheet. It's not just the ESP32 and flash chip, there's a 40 MHz crystal and some matching components too. So it's a full SiP with embedded passives on a four layer substrate! This is a lot more interesting...

Angled view of ESP32-PICO-V3 cross section showing the two stacked dies and a ceramic capacitor
10 Mar 2023 at 0:18 | Open on ioc.exchange
Andrew Zonenberg

Colored interference patterns on the plates of the ceramic capacitor seen at low mag. You can tell just how dense modern MLCCs are!

Closeup of a ceramic bypass capacitor in the cross section, showing red and orange interference patterns reflecting from the the plates
10 Mar 2023 at 0:20 | Open on ioc.exchange
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