Recent Posts

1

Beginners / Re: Convert US standard 115V to International 230V

« Last post by BeBuLamar on Today at 01:19:37 pm »

IanB suggested to use the Kill-a-watt which is kind of cheap but it's not Chinese. It's Taiwanese. The Taiwanese is not pleased if you call them Chinese.

2

FPGA / Re: ATF1502 programming & 'wrong' id (fake?)

« Last post by dolbeau on Today at 01:18:35 pm »

Thanks for the answers.

The JTAG circuit is fairly trivial - just the pin header for the USB blaster [clone], and the ATF1502ASL, nothing else. Pinouts was double-checked against both the datasheets and for the ATF1502ASL the original design (it has a different connector). SVF file for basic stuff like erase, and for programming+verify, all work with no issue provided they are changed to the actual ID of the chip.

Preliminary tests with a much simplified code in the CPLD designed purely for testing suggests the chip works as advertised, at least with this simplified design. So it's likely the chip are actually ATF1502ASL (or clone thereof), and probably close enough for my hobbyist use case.

But still wonder why those JTAG IDs are 'wrong'...

3

Projects, Designs, and Technical Stuff / Re: Homebrew Lock-In Amplifier

« Last post by Kleinstein on Today at 01:18:17 pm »

With very high gain and precision in mind it is usually better to have a single ground point (star ground). A ground plane is more thing to avoid EMI and good for a digital circuit.
The point with a lock-in amplifier is to keep the input and reference part separate, so avoid the ref. side to cause any input signal with the same frequency. In the plan there is not yet much for the ref. side. For quite some applications one would want a phase adjustment there.
One would want at least some protection.

If one needs fine steps with the gain depends on what is used to read / display the output: with an analog meter one may need 1, 2,5,10 steps for the gain. With a digital read out with sufficient resolution steps of 1 , 10, 100, 1000 are enough. Only a gain range from 1 to 100 may be a bit small. 
Depending on the precision of the amplifier at the input one may want a 2nd AC coupling step before the phase sensitive detection.
The display / output side also determines how much gain is useful at the output (DC) side. With a rel. low resolution ADC or an analog movement one can use quite some DC gain there. Chances are the AD630 output can be stable to something like 10 µV. So the output side should ideally be able to resole to that level. If a good dmm is used the range settings there can provider some of the total gain.

4

Programming / Re: Linux Dependency Black Hole

« Last post by mag_therm on Today at 01:10:01 pm »

Thanks for the encouraging replies.

The software project I did was actually the largest  single project of my whole engineering career,
It is a numerical simulation of electro thermal process.
Took more than 5 years for me to develop, about 350 k lines of code and uses multi core parallel processing.
Trips around the world to various steel processing plants to measure and verify the accuracy.

At the start I intended multi platform and was going to use C.

Due to deployment and maintenance world wide and expected life of 20 years,
I looked at various "friendly" IDE and eventually selected Xojo.
There were to be no dependencies and the whole application was to be in user's space.
I used a pro programmers initially to do the GUIs and the sqlite.
And client's engineers assisted with scada/plc interfaces

Fairly early in the project, having trouble, we decided to abandon multi platform and just use linux.
We were fortunate that the original code and graphics continued to function over many Xojo updates from 2008 to 2019.
 But in 2019 XoJo did major changes to graphics and so we also had to do an update taking a few months

I suppose all that total experience is how I came to dislike dependencies and to rely on IDE !

And yes, I am partly doing this HackRF1 firmware job to try to keep up to date, as well as hopefully improving the FOSS firmware.

5

Thermal Imaging / Re: HTI HT-203U 256×192 thermal imager for Android phones

« Last post by ArcSin on Today at 01:09:35 pm »

Anyone has any clue where you could get the Tiny1-C 256x192 infrared module without the rest of the dongle?

I have seen cheap dongles that contain it, but when i try to look for actual module without anything else, the price goes up like it just spotted a spider on a toilet chair.

6

General Technical Chat / Re: Cable Management

« Last post by Wallace Gasiewicz on Today at 01:06:52 pm »

I use something like nfmax.  I use storage bags and put them into expandable files. These are the ones for paper files and kinda resemble accordions..

7

Thermal Imaging / Re: My decent in to Infrared abyss (IR microscopy and telescopy, on the cheap)

« Last post by ArcSin on Today at 01:06:27 pm »

Thanks for sharing, definitely will have a look!

Also, 150mm f/1 IR lens? That cost like arm and a leg. 

8

Beginners / Re: uCurrent Gold Schematic

« Last post by xvr on Today at 12:57:45 pm »

Remove Q1 from programming circuitry - it was originated in ESP8266 and blindly migrated to ESP32 by some 'clever' Chinese engineer (or student, I don't sure). For ESP32 it really prevent it from programming at all.
And consider take ESP32-S3 or ESP32-C6 based modules. They have on-board USB-to-JTAG adapter and do not required external programming circuitry

9

Projects, Designs, and Technical Stuff / Re: Insulation between motor laminations?

« Last post by strawberry on Today at 12:56:34 pm »

must electrically insulate windings(so that vibration and dirt). other thing is esthetics

10

General Technical Chat / Re: The strange case of phase angles

« Last post by Andy Watson on Today at 12:54:55 pm »

The impedance of the capacitor should be combined with the impedance of the inductor in parallel; you appear to have combined them in series.