Recent Posts

1

Test Equipment / Re: Oscilloscope Music on DSOs- Post your Results

« Last post by joeqsmith on Today at 12:38:15 am »

I recorded my demo by playing the youtube video into my 'scope.

I don't know if youtube audio compression would have any effect.


If anybody has an mp3...

Yeah, you need better quality. You can download wav files here: https://drive.google.com/drive/folders/1UHvGC6-TDywFri7am8YJl5G6svK33qhC

PC sound card to scope good enough?  Wouldn't think with audio, we need much?   Seems I tried it before with miserable results.   PC scope software out performed it by a mile. 

2

Test Equipment / Re: Looking for a replacement general purpose oscilloscope for home use

« Last post by joeqsmith on Today at 12:34:17 am »

...
I hope he had some kind of refund from the seller. Finding a replacement motherboard (with pcie/104 and LVDS onboard) is not going to be easy nor cheap.

If I were the seller and saw someone pulling my equipment apart like this with total disregard to basic ESD practices, I would not only reject any claims, but most likely would make a video rant about wannabes.     

Most likely his problem is a contact issue. FR4 boards are sturdy and can take quite a bit of bending. But it is possible the previous owner messed it up doing the SSD upgrade and sold it on.

I had a very similar symptom crop up with my cheapo Diglent ARTY board that I was using to test a scope I was looking at.  Touch the USB and it would take down the PC.  Under the microscope, there was a solder ball down under the connector.  I would have started by inspecting the connectors. 

I would like to have that scope.  Newer MB than my old one.  Guessing much faster.

3

Projects, Designs, and Technical Stuff / Re: Design of white noise generator for bathroom??

« Last post by Geoff-AU on Today at 12:34:01 am »

Maybe reading this book would help the wife

https://en.m.wikipedia.org/wiki/Everyone_Poops

Then again, maybe OP really gives the thunderbox its name.

In either case it would be remiss of me not to say that you definitely want brown noise to mask it

We have a Dohm Classic (for assisting with sleep, not household peace at pooping time), these units are good for masking sounds, and they have a real fan in them not some awful speaker making a jarringly useless attempt at producing broad spectrum masking.

http://thedohm.com/

4

Projects, Designs, and Technical Stuff / Re: Design of white noise generator for bathroom??

« Last post by MarkF on Today at 12:33:37 am »

When I built my house, I had the bathroom walls filled with fiberglass insulation.
The builder thought I was nuts until I told him why.  No more bathroom sounds.

It would mean tearing into the walls though...

Or.  Just turn on the exhaust fan.

5

Manufacturing & Assembly / Suggestions for Taiwan PCB house that does small-ish orders?

« Last post by Rat_Patrol on Today at 12:33:12 am »

I typically order about 400 boards at a time, so not big, not tiny.

I'm just re-shopping around the non-Chinese PCB fab houses, see if I'm still happy where I currently go (U&I in South Korea usually). I handle my own assembly.

6

Projects, Designs, and Technical Stuff / Re: Design of white noise generator for bathroom??

« Last post by shabaz on Today at 12:32:20 am »

A quick/ugly hack could be to use an MP3 player board. Admittedly over-the-top in terms of the underlying tech!, but cheap(ish) and easy to try different sounds etc. Or maybe just a bathroom/shower radio, tuned on AM to no station.

7

Repair / Re: SMPS over voltage?

« Last post by xavier60 on Today at 12:25:01 am »

Can you check for output ripple or have you replaced the output capacitors including C106? What is the value of C106?

8

Mechanical & Automation Engineering / Boston Dynamics New Humanoid Robot

« Last post by EEVblog on Today at 12:20:38 am »

 



https://bostondynamics.com/blog/electric-new-era-for-atlas/?utm_campaign=cy24q2-atlas&utm_source=facebook&utm_medium=social

9

Projects, Designs, and Technical Stuff / Re: Buck loop stability tuning

« Last post by zphaze on Today at 12:19:57 am »

Well, I suppose I got my answer somewhat. If you guys don't readily see issues I guess I wasn't too far from what I thought was about right for a start.
Phase margin is >60° and gain is high for smaller phase values, so I guess I'll take this as "good enough" and go ahead.
I'll still plan for added capacitance in case of unexpected/stronger derating.

As for the transient model I don't have models from TI for this controller so I'll stick to the bode plots for now.
Simulation makes thing easier I'm 100% with you on that.
UseCFF adds a pole and a zero obviously, so I would suppose its 3rd order at least.

10

Metrology / 0.1 Hz to 10 Hz Passive Filter

« Last post by Alex Nikitin on Today at 12:07:58 am »

This is not a replacement for a "proper" noise measuring amplifier/filter as discussed in other thread(s). However I made this filter to measure and compare LF noise on HP3245A and other sources with not the lowest noise levels and it is perfectly useable for this purpose. The filter is connected to the input of a (slightly modified, hence "M") Keithley 2015M set at 1NPLC and 100mV DCV. The self-noise of Keithley with a shorted input is below 1uV p-p, with the passive filter connected it increases to about 2uV p-p - or about 0.2ppm at 10V DC input. The components are what I had at hand, a pack of 2.2uF polypropylene capacitors, a small diecast box and a 3-position switch (to defeat the filter fully or only the LPF part, the switch and the protection diodes are not shown on the circuit).

The advantages of a relatively small PP capacitor are very low leakage (picoAmps) and very fast settling time if the DC voltage is changed. The disadvantages are  higher noise, first order filtering and a slight attenuation (about 2%, so can be considered benign).

Cheers

Alex