Projects - All Comments

RE: Fundamentals of Electronics: Understanding Resistors, Capacitors and Inductors

DAB — Thu, 22 Oct 2026 19:37:54 GMT

Nice quick overview of electronics fundamentals.

RE: DIY Test Equipment: Building a Modular 32-Channel Python SCPI Logic Monitor

LostInSpace — Tue, 20 Oct 2026 22:59:51 GMT

Wonderful. I also have a lab full of 'home made gear' in those Hammond Boxes. You learn more than can be imagined from building your own stuff and it can be designed 'just so' for our needs. I likewise tend to use SCPI-ish communication language for the IO commands. Easy to remember syntax, and any documentation that you need to do tends to come out already organized nicely.

Perhaps for next time, you can save some layout time (and drill bits) on stitching vias.... I know many folks panic about stitching vias on PCB's and tend to just throw in thousands (I've done it myself). When I learned RF, I found that there is some easy analysis that shows just how many are 'enough' and any more don't help at all - only consume time putting them in.

At DC even a very small via has a DC resistance in the milliohm range, so they don't heat up or drop much voltage. In fact it has been shown that the trace temperature really controls the via temperature, so even at DC more than one via is overkill, See,

https://www.signalintegrityjournal.com/articles/1459-vias-are-cooler-than-we-think

With thermal vias it has similarly been shown that more then 3-5 in a small area does not improve the thermal situation further, see,

https://www.edn.com/pcb-design-a-close-look-at-facts-and-myths-about-thermal-vias

As for RF - the goal is to not have any appreciable voltage formed between the ground vias at RF frequencies. There is a science that can be applied to this - or put another way - "Why not riddle the board with vias?" which would be silly, so then "How do we know when to stop?"

Turns out you only need to stitch vias at every 1/8th of a wavelength or so. For typical designs today we deal with around 4nSec rise times, including USB Full Speed. This equates to around around 100 MHz bandwidth. 1/8th of a wavelength on FR4 at 100 MHz is around 150mm. Even at 2.5 GHz the distance is 6mm. So really we don’t need all that tight of stitching at all, much less than ‘intuition’ alone would lead us to believe.

This 1/8th Wavelength rule can be proven by measurements and simulations. See,

https://www.edn.com/via-spacing-on-high-performance-pcbs/

https://archive.org/details/does-copper-pour-on-a-signal-layer-decrease-isolation/

Additionally this 1/8th rule also applies to EMI containment on a PCB, proving that it is an adequate rule. See,

http://lamsimenterprises.com/Controlling_EMI_Emmissions_From%20PCB_Edges_WhitePaper_iss01.pdf

Now we know when to stop, and can stop worrying about if we have enough stitching vias or not. :-)

Have fun and keep up the good work. :-)

RE: DIY Test Equipment: Building a Modular 32-Channel Python SCPI Logic Monitor

michaelkellett — Sat, 17 Oct 2026 17:04:51 GMT

In the video you invited comments re. the "controversial" protection ciruit.

Were you by any chance referring to the fact that it will try to clamp any applied voltage to your internal 3.3V rail - so if you accidentally connect to an external power rail something will get cooked.

You need resistors on either side of the schottky diode pair.

This design isn't trying to run fast so you should make the input resistor as large as you can to get the best protection. 1% of the ADC input impedance seems like a good start, which is 30k.

If you use 75V rated 0603 parts you should be OK with up to 50V. That gives a max power in the resistor of 80mW which is a reasonable place to be.

The 1k between the diodes and the ADC is probably OK - there isn't enough information in the TI data sheet to be certain - the ADC will be safe enough but there might be enough current affect measurements.

Ideally the input clamp should not clamp to 3.3V but to a slightly lower voltage but it does all get a bit messy if you need to do that.

An input shunt capacitor is often a good thing ...........

RE: DIY Test Equipment: Building a Modular 32-Channel Python SCPI Logic Monitor

kmikemoo — Sat, 17 Oct 2026 02:26:33 GMT

Great project, [mention:c1a817edc53a434fb85a9f592f23c825:e9ed411860ed4f2ba0265705b8793d05] ! It's a very nice piece of test equipment. Well done.

RE: DIY Test Equipment: Building a Modular 32-Channel Python SCPI Logic Monitor

DAB — Fri, 16 Oct 2026 01:22:03 GMT

Very cool project Clem.

I like the idea of using the ADC on digital lines.

It is a good way to see if you are getting any crosstalk or spurious signals.

This project took me back to when I programmed an early version of a digital oscilloscope back in 1982.

We were sampling radar patterns and analyzing the data.

RE: DIY Test Equipment: Building a Modular 32-Channel Python SCPI Logic Monitor

manojroy123 — Thu, 15 Oct 2026 13:03:26 GMT

Very interesting project.

RE: Combining Zigbee, Raspberry Pi and Computer Vision for a Smart Family Planner

kmikemoo — Wed, 14 Oct 2026 03:02:40 GMT

Very cool! I do like the facial recognition login. [emoticon:fbd079a1c4f748c5a234faee215de9cc]

RE: Fundamentals of Electronics: Understanding Electricity, Voltage, and Current

Peterb26 — Fri, 09 Oct 2026 19:35:22 GMT

Which video next please? Enjoyed that one… [emoticon:1435ff2429184e17bc948e4f19178e1e][emoticon:1435ff2429184e17bc948e4f19178e1e]

RE: Combining Zigbee, Raspberry Pi and Computer Vision for a Smart Family Planner

DAB — Thu, 08 Oct 2026 19:59:32 GMT

Nice project.

RE: Fundamentals of Electronics: Understanding Electricity, Voltage, and Current

IgnatiusA — Thu, 08 Oct 2026 19:51:16 GMT

I think this idea has a lot of potential (pun sort of intended). It would be fantastic to be able to have somewhere to point people (including me) to say 'start here'.

Only issue is, as a new user, it looks to me like the individual episodes are going to get lost in a sea of other more complicated projects. It would be good if these episodes could be pulled out into a playlist in their own dedicated area of the website to keep the noise to a minimum.

RE: Combining Zigbee, Raspberry Pi and Computer Vision for a Smart Family Planner

beacon_dave — Thu, 08 Oct 2026 18:42:49 GMT

Have you got a process active in the background which shuffles allocating a task to the user, or is it always the same task allocated to the same user when pressing a button ?

I guess another way of doing it might be to allocate the next task to the next user in turn. Although if doing this, then you probably want some immediate feedback in case it gets allocated to yourself, in which case you would probably want to know so as you can do the task there and then.

I can perhaps see the remote button being a bit limiting as a user interface if you want to develop the system further. There might be a future project waiting. [emoticon:c4563cd7d5574777a71c318021cbbcc8]

RE: Combining Zigbee, Raspberry Pi and Computer Vision for a Smart Family Planner

spinden — Thu, 08 Oct 2026 14:36:41 GMT

What a fun project! Thanks for sharing

RE: Fundamentals of Electronics: Understanding Electricity, Voltage, and Current

DAB — Tue, 06 Oct 2026 19:28:33 GMT

What if I told you that all electronics really work on photon flow, not electron flow?

Need proof?

Every electronic arc is visible because of the photons being dispersed from the flow.

No one has ever proven that you can rip an entire electron from an atom and have the atom stay intact.

Photon exchange between atoms better explains the phenomenon.