Recent Posts

41

Beginners / oscilloscope problem

« Last post by mike_mike on Today at 04:59:24 am »

Hi! I recently bought a new oscilloscope upo1102cs from uni-t. It is working ok, until I connect it using utp cat5e cable to the router. On the same router is connected the pc. The wan cable that enters into the router is coming from the main router. I can easily access the oscilloscope from the pc, I can see the waveforms on the pc, but if I navigate in the menu of the oscilloscope webpage, after a while it appears again the login screen, and after I enter the username and password, it gives me a error and the oscilloscope freezes on the benchtop and it gives me a time out error on the pc.

What should I do ?

42

General Technical Chat / Re: Need 13Amp variac device to 'modulate' a water boiler.

« Last post by ealex on Today at 04:58:38 am »

Hello

I've used a dimmer from a "home improvement" store, with 2kw heating elements. I think I had crimp-on ferrules on the cables, and had no issues with overheating. (it was an experiment but lasted way more than expected).

You need to boil it for 2 reasons:
1. Loose some water, so you have a higher sugar % when you start the fermentation - might or might not be desirable - it depends on your recipe and the final volume you can ferment and bottle, but usually diy mashing is not that efficient - you tend to end up with a lot of low concentration worth if you try to wash out all sugars from the mash.

2.  Help the bitter compounds dissolve into the beer - might work under the boiling temperature as well - this is also where the 1h boiling time comes from. There are some formulas to estimate the final bitterness from the alpha acid content of the hops you add and the boiling time it sees - the "start of boil" addition will give most of the bitterns but no flavor (or even some unwanted flavors), the last addition will add almost no bitterness and a lot of flavor (for an IPA for example)

I've build my gear from old stainless steel kegs - cut the tops off and re-use the "crown" ( i don't know the proper name ) for the handles that are already there.
Those worked ok with electric and propane heating, but I had to insulate the boiler - a few layers of cardboard where enough to reduce heat loss and easily to replace.


One issue with electric heating: the sugars tend to caramelize and burn on the surface of the heating elements -> you either need very good agitation or heaters that have a high surface area.

One more thing to consider: rapid cooling after the boil - it prevents volatile compound loss and will reduce the time period when the beer can be infected - when it's too hot to pitch the yeast but cold enough for random spores / bacteria to survive.

43

Test Equipment / Re: Siglent SDS800X HD 12 bit DSO's

« Last post by rf-loop on Today at 04:47:10 am »

Just out of curiosity : is also your 2000X HD behaving in the same way ?

I didn't notice anything like that at the time, but I can check it at work with an SDS2104Xplus (I no longer have the 2504X HD).

SDS800X HD Math fuctions update rate slows down when any activity by mouse or touch and same happen also in SDS2000X HD and SDS3000X HD (and big SDS800X HD aka SDS1000X HD but tested only using old version 1)

After touch or mouse activity end, normal speed is returned after around 1-2 second.



Imho, this is a feature. For now. Whether it can be optimized / improved somehow,  remains to be seen. Of course it is nice if there is way to do it so that is works independently.

At least in my case, this feature has never made it difficult to use the machines for their intended purpose as a tool. I classify it mostly as a cosmetic "disadvantage" for now.

Of course, I don't use a mouse like in some games maybe by waving it more or less all the time. I only touch it when it is necessary and only for that time. Instead, if the mouse is in hand contact all the time, that way of using it might keep it active all the time and drop the math update speed almost constantly.

44

General Technical Chat / Re: Do you think an LED is a resistor?

« Last post by Someone on Today at 04:46:30 am »

non linear system has linear approximation around a small operating point....

STOP THE PRESSES!

... oh wait, that's the underlying principle of how spice AC analysis works.

45

Manufacturing & Assembly / LPKF Protomat S42: Machine "shock absorber"/"stroke limiter" tuning

« Last post by rsaxvc on Today at 04:43:13 am »

I've bought a Protomat S42 from a college that changed their curriculum. The machine configuration disk was long ago lost. I've been able to reinitialize the machine to learn its limits and approximate a new home position, I can warm up the spindle and drill holes. It's time to create a "New Reference Hole System", and I'm working through those steps in the manual, but when I go to drill the hole using the 2.95mm reference bit, it just barely doesn't touch the reference strips.

It seems the component known as the "shock absorber" or "stroke limiter" is preventing the drill bit from drilling deeper than roughly the height of the aluminum bed / reference strips. Preventing drilling into the machine bed, sounds like a great idea, but I bet I've got to disable that safety while drilling the reference holes. I've attached an image showing the rough location of the limiter and a diagram of the right-side of the head where it is located. I was hoping you could help me with any of the following questions:

• Is the shock-absorber's purpose to prevent crashing the drill into the machine?
• Is there a way to temporarly bypass it, without affecting the height it is set to?
• If I need to adjust for reference hole drilling, how do I set the appropriate height so the holes are a good depth?
• If I need to adjust for reference hole drilling, what is the right height for resetting it afterwards, and how do I do so?

46

General Technical Chat / Re: Big Brother air monitoring.

« Last post by Geoff-AU on Today at 04:40:48 am »

My response:  "No.  No sir it is not 'just' that, not even close."  From a single sensor of this calibre in the house I can tell a whole LOT more than my air quality.

At some point it becomes unsettling, yes. 

Honourable companies are not obligated to stay that way, either.

47

Microcontrollers / Re: $0.11 PY32F002A: Cortex-M0+ MCU, actually a PY32F030! 32/4KB, 48MHz, PLL, DMA...

« Last post by John_doe on Today at 04:36:39 am »

I'm writing a summery of what I did to program these PY32F002A chips. Maybe it'll help some other n00b to save some time:

1. I installed PY32Duino for the Arduino IDE. I just followed the instructions here (used Google to translate the site to English):
https://arduino.py32.org/

2. Wrote a simple test sketch and compiled it. To upload it to the TSSOP-20 version, I just connected a USB to TTL module (costs less than $1 on AliExpress) and uploaded from the Arduino GUI. Instructions on how to connect the module to the chip can be found here:
https://github.com/wagiminator/MCU-Flash-Tools?tab=readme-ov-file#puyaisp

3. To write to the chip packages that do not have a BOOT0 pin, a programmer was needed, I didn't have a suitable one, such as these that were recommended in this thread:
https://www.aliexpress.com/item/1005003620126365.html
https://www.aliexpress.com/item/1005005179354439.html
So I used an ST-Link v2 clone to write this firmware to an STM32F103 "Blue Pill":
https://github.com/RadioOperator/STM32F103C8T6_CMSIS-DAP_SWO/blob/master/build/F103-DAP-SWO-CDC-BLUEPILL-SWD_REMAP.hex
To do that I used STM32 ST-LINK utility from this link:
https://www.st.com/en/development-tools/stsw-link004.html
I had to hold the reset button while pressing Target>Connect . Connections from ST-Link to blue pill are 3.3v->3.3V ; GND ->GND ; SWCLK->SWCLK ; SWDIO->SWDIO.

4. After I had a working CMSIS-DAP, I took the compiled Arduino hex file (if you don't know where to find it, google it) and used OpenOCD. To do that I downloaded the OpenOCD package that already includes the PY32 support files from the PUYA gitee:
https://gitee.com/puya-semiconductor/tools-and-software/blob/master/PY32_GCC/openocd-0.12.0.zip
(Thanks IOsetting and DavidAlfa for the link)
I had to modify the "openocd_run.bat" file to include the ".\bin" folder:

Code: [Select]

.\bin\openocd.exe -s ./scripts -f ./scripts/interface/cmsis-dap.cfg -f ./scripts/target/py32f002x.cfg
5. Had to enable Telnet for my Windows 10 (google it if you don't know how) from the control panel.

6. To connect the blue pill CMSIS-DAP to the IC, I connected the USB of it to my PC and from the blue pill to the PY32F002A the connections are: 3.3V->VCC ; GND->GND ;  SWCLK->SWC ; SWDIO->SWD. For the SOP-8 Package, the pins are 1 ; 8 ; 4 ; 5, respectively.

7. To use OpenOCD, I ran the batch file and in a new command prompt window I entered:

Code: [Select]

telnet localhost 4444And then the following commands:

Code: [Select]

reset halt
flash write_image erase c:/myfolder/myfile.hexNotice the forward slash in the path to hex file. The command will fail if a Backslash is used.

48

Manufacturing & Assembly / Re: Fellow LPKF equipment users?

« Last post by rsaxvc on Today at 04:25:52 am »

Hi! I'm a Protomat S42 owner, hopefully soon to be operator.

@rodsolder, my machine came second-hand with a few boxes from Think & Tinker's bits, available from Colorado, USA, at https://www.precisebits.com/ . I haven't gotten my machine up so can't vouch for them, but they are cheaper than LPKF bits.

49

General Technical Chat / Re: A serious (as in not troll) requestfor help w/ultrasonic transducer

« Last post by coppercone2 on Today at 04:25:01 am »

what in a watch requires this nonsense? The only part where its not cringe worthy is prep before plating. then its important to be really clean, for the highest quality. But its little more then careful rinsing wiht clean stuff. Optics seems harder to clean because of scratching, and fragile thin films... but its only a problem if you basically don't spend any time researching and don't spend any more (as I found out with some laser stuff, because its basically plastic coated and there is some incompatibilities that seem like nonsense to any home owner that has glass (late roman empire ) (no ammonia))

The main issue is to remove old, dried on lubricant, and various particles of dust and grit that might be hidden away in crevices and pivot holes where they can cause major problems.

It's only the mechanical parts that go into a cleaning machine. Decorative parts need careful and separate treatment to avoid ruining them.

Here is a video that shows what the whole process is about, using a non-ultrasonic machine:

yeah but the purity requirement seems to be for ICP machine calibration standards. I mean they should just do something reasonable like demand you dress like the swiss guard while working on the watch in their 5000$ dress uniform

50

Microcontrollers / Re: $0.11 PY32F002A: Cortex-M0+ MCU, actually a PY32F030! 32/4KB, 48MHz, PLL, DMA...

« Last post by John Celo on Today at 04:21:33 am »

That being said, SOP-8 is pain in the ass to work with, you functionally have 3 pins left (VCC/GND/SWC/SWD/NRST) if you don't remap SWC/SWD/NRST - and I dont think it's worth bothering with that. SOP-16 is just a better fit for a beginner, since you can hook up uart and have some extra printfs diagnostics messages ON TOP of debugger. I also use uart to send commands from my computer to the chip.

Wait, only 3 pins? Does that mean that if I use the SWC/SWD pins in my Arduino sketch, I won't be able to write to the chip again 

The chip is gone if you reassign both SWC/SWD and NRST.
If you have SWC/SWD reassigned, but NRST is still available, you can still flash the chip if you pull NRST low (which forces the SWC/SWD pins to get reassigned to defaults).

What I mean by saying "3 pins" is - that during development, you will probably want to have SWC/SWD connected all the time as you iterate and work on your design & code.

If you reassign SWC/SWD you'll have to have some way to share those programming wires with whatever peripherals you want there and have some way to connect/reconnect those - not to interfere with flashing, as well as have to hold NRST while programming.

It just seems like a hassle for no real benefit? Price is the same, and package is roughly the same size as tssop20.

I bought a few py32 sop8 chips myself, and retrospectively that was a mistake, with so few pins there's not much I can use them for.