Blog - All Comments

RE: SSFG - Simple stupid function generator

kevinmp — Mon, 18 Nov 2024 05:47:05 GMT

have a look at dac function generator https://github.com/RobTillaart/FunctionGenerator

RE: DIY 3-D Printed 4-Wire Kelvin LCR Adapter for SMD Components

Jrussell88 — Tue, 31 May 2022 15:10:40 GMT

Nice project. Are you publishing the PCB files?

I'd like to use them with the Kelvin Clamps which I will modify to make the leads pluggable.

RE: DIY 3-D Printed 4-Wire Kelvin LCR Adapter for SMD Components

michaelkellett — Fri, 08 Oct 2021 08:40:39 GMT

Very nice !

RE: DIY 3-D Printed 4-Wire Kelvin LCR Adapter for SMD Components

DAB — Thu, 23 Sep 2021 18:09:45 GMT

Great solution to those very small components.

DAB

RE: DIY 3-D Printed 4-Wire Kelvin LCR Adapter for SMD Components

shabaz — Thu, 23 Sep 2021 17:03:25 GMT

Hi Frank,

Very interesting adapter! I didn't think it was possible to 3D-print a mechanism to grip such an SMD part. Really nice design, and they look so well made I would not have realized they were home-made from the photos.

Great color scheme too!

RE: DIY 3-D Printed 4-Wire Kelvin LCR Adapter for SMD Components

genebren — Thu, 23 Sep 2021 13:53:27 GMT

Very well done project and blog! I really like your attempt at an SMD clamp for holding the part in place while you measure its value. I wonder if a flip-top adapter (similar to programming adapters for smd chips) could be fabricated cheaply as another approach?

[View:/resized-image/__size/307x262/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-a1385e17-e448-4da2-ad43-ac9665277163/contentimage_5F00_216523.jpg:307:262]

Another idea might be something along the idea of a 4-jaw chuck, like on a lathe, scaled way down, to hold the device under test?

Another enjoyable and informative blog, keep up the great work!

RE: DIY 3-D Printed 4-Wire Kelvin LCR Adapter for SMD Components

Andrew J — Thu, 23 Sep 2021 07:37:01 GMT

Really good work Frank. Looks like it would be a good addition. At the moment I have to use large Kelvin tweezers and they are awkward to get a good contact on 0805 parts.

RE: Viewing Noise with a Measurement Amplifier

phoenixcomm — Thu, 26 Aug 2021 13:41:52 GMT

[mention:b0bc65b9ecdc4307bd967592f00e340a:e9ed411860ed4f2ba0265705b8793d05] oh, my great stuff. the analog stuff is over my head.

looks professional!

~Cris

RE: The Missing Link (BBC-PCB)

dougw — Thu, 26 Aug 2021 12:51:59 GMT

I'm surprised the swag idea didn't get any traction. Even though I don't use breadboards much, I would prefer getting a BBC-PCB as a swag item to getting a mug or a T-shirt.

RE: 3D Printed Surface Mount Test Lead Tweezers

Workshopshed — Thu, 26 Aug 2021 07:31:30 GMT

I think the PCB ends could be an interesting experiment. May be a 45⁰ angle?

Quite fancy making my own set of these.

thanks Frank.

RE: DIY 100kHz VCO - Build & Test

shabaz — Mon, 23 Aug 2021 14:53:20 GMT

I tried experimenting over the weekend with a low-cost scriber, to see if it could become a more useful tool for copper clad.

I think the results were just average, and probably the perspex cutter tool you mention may be better. Anyway, it kind of works.

Basically I took a Dremel grinder wheel to it, but that had zero effect, so then a diamond-coated slitting wheel was attempted (with it partially in water so that it wouldn't overheat the scriber tip). It was all handheld dremelling so there's no accuracy, but I managed to make a groove in the scriber.. seems to scoop out copper+FR2, good enough for the few times I need to do it.

I don't know what the optimal shape is.

Anyway, the workflow with this is to either first cut a line into the copper using a craft knife, or just skipping that and just using the grooved scriber in a single step.

[View:/resized-image/__size/620x483/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-ef0670d0-c2b5-48f9-8a02-9ec5ef39e4d4/contentimage_5F00_208546.jpg:620:483]

RE: Viewing Noise with a Measurement Amplifier

shabaz — Fri, 20 Aug 2021 21:19:36 GMT

Quick photo showing the front panel assembled! The enclosure could do with a rubber surround : )

I finally found some suitable button caps on Aliexpress and have ordered them, currently I'm having to push the buttons with a pencil! but I needed to use it so I couldn't wait for the button caps to arrive.

The photo shows it measuring the noise from a homemade battery-operated supply (there is a Lithium camera battery inside there with a charging circuit). This is a very crude supply that was assembled in the past for just one experiment when I needed a lower noise supply than a bench supply. It contains a REG101 voltage regulator, and only outputs 5V up to 100 mA.

[View:/resized-image/__size/939x548/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-e4b59325-e032-46a7-81c7-892e4beb029b/contentimage_5F00_208526.jpg:939:548]

With the 10 kHz filter enabled and set to 100X gain, in the screenshot below the automated measurement at the bottom shows the noise to be 1.3mV RMS, so divided by 100 that's 13uV, which is quite low noise! The datasheet says it should be 35 uV RMS, but that's specified for 100 kHz bandwidth.

[View:/resized-image/__size/620x372/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-e4b59325-e032-46a7-81c7-892e4beb029b/contentimage_5F00_208527.png:620:372]

With the 10 kHz filter disabled (i.e. a bandwidth of over 500 kHz), I see this:

[View:/resized-image/__size/620x372/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-e4b59325-e032-46a7-81c7-892e4beb029b/contentimage_5F00_208528.png:620:372]

The measurement there is 3.4mV, which is 34 uV RMS, and that's almost spot-on compared to the 35 uV RMS at 100 kHz bandwidth value in the datasheet! I've not taken the noise of the amplifier into account. So everything is definitely in the right ballpark, and reasonable enough for relative measurements too.

I'm thinking the measurement amplifier should have a 100 kHz filter setting (i.e. settings of 1k, 10k and 100k rather than 100Hz, 1k and 10k), since 100k is so popular in datasheets, and would mean the measurement amplifier noise would barely need to be taken into account for most measurements, since it is low (about 3.7 uV RMS) up to around that ballpark. Anyway, for now I'm happy it is functioning good enough to use, and maybe at a later date the RC filter components could be recalculated. I've attached modified front panel files in export-alu-100k.zip in case anyone wishes to make use of that.

[View:/resized-image/__size/620x324/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-e4b59325-e032-46a7-81c7-892e4beb029b/contentimage_5F00_208529.png:620:324]

Aliexpress buttons; they need a 2.8 x 2.8 mm hole:

[View:/resized-image/__size/620x408/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-e4b59325-e032-46a7-81c7-892e4beb029b/contentimage_5F00_208530.jpg:620:408]

RE: Pico Puffer

dougw — Mon, 16 Aug 2021 19:26:46 GMT

Your project is looking good.

If you use 2 metallic probes, each in a separate plastic bag, you can put water in each bag to eliminate air.

Actually only 1 probe needs to be insulated with a plastic bag, the other probe can contact ground moisture directly.

RE: Pico Puffer

robogary — Mon, 16 Aug 2021 16:48:00 GMT

Cool project.

Its great that Pico Puffer got to enjoy some beach time this summer. I'm jealous :-)

RE: The Missing Link (BBC-PCB)

genebren — Sun, 15 Aug 2021 17:24:10 GMT

Very clever idea!

I have not run into too many cases where I need access to a connector/cable, but I often run into cases where I need to communicate with a device on a breadboard. I have hacked up a couple of connectors on to a board that I developed for a client years back and use it to bridge USB to UART, I2C or SPI. I write a quick and dirty VB program to drive the USB/serial port on the board, which is connected to an ATmega328PB. I then write firmware for the board, to convert the USB/serial traffic into the appropriate UART, I2C or SPI data streams. In this case I was sending UART data to a MP3 player modules along with some discrete signals.

[View:/resized-image/__size/620x465/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-9be0d1ae-c59b-4c2d-8fb5-f1ab032fc38e/contentimage_5F00_208634.jpg:620:465][View:/resized-image/__size/620x465/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-9be0d1ae-c59b-4c2d-8fb5-f1ab032fc38e/contentimage_5F00_208635.jpg:620:465]

I can see where a hand full of custom modules could make your breadboarding experiences a little more pleasurable.