Recent Posts

1

Microcontrollers / Re: How to create custom bootloader in esp8266

« Last post by tooki on Today at 04:06:06 pm »

Thank you for taking the time to answer my question. I was wondering if there would be any problems booting the program if the power goes out while updating the ESP8266 firmware?

The worst-case scenario is that you have to use serial/USB to reflash the firmware. But IIRC, the OTA mechanism in ESP-IDF at least theoretically can recover from an outage.

2

Repair / Re: LG 3D 4K TV repair - UB980 range 65UB980 79UB980 84UB980

« Last post by 3DMovieList on Today at 04:04:00 pm »

Nice work!  Thanks for posting!
Now, what does "Driver On Signal error" mean?

3

Thermal Imaging / Re: Calculate thermal camera lens specifications of Flir B4xx T4XX E6X

« Last post by radioorizont on Today at 04:03:16 pm »

Yeah I have one of those too but not happy with qua6, I think germanium coated lenses are much superior.
Price wise a ZnSe is £20-30 and germanium is £100+ though so I get your point.

4

Microcontrollers / Re: primitive serial CLI / Console for embedded systems - Ideas for implementation?

« Last post by tooki on Today at 04:01:58 pm »

And one extra question.
Does it make sense to optimize the CLI for VT100/Putty/miniterm type of communication (each character transmits immediately after the keypress) or for terminals that "wait for enter" (e.g. Termite) and send the whole line?

Does that matter?

The important thing, IMHO, is that you parse the command as a whole, so that you can perform input sanitizing on the entire input as a whole.

5

Projects, Designs, and Technical Stuff / Re: Lars DIY GPSDO with Arduino and 1ns resolution TIC

« Last post by bogdanbrudiu on Today at 04:01:45 pm »

Can you please help me? I am stuck and don't know what I did wrong...
If I disconnect the TIC from ADC0 and measure the TIC output it looks like this

If I connect it to ADC0 the entire signal goes up 1V and looks like this


When connected the ADC0 reading is 1023 if I disconnect it the reading is ~200 and the console shows 10MHz?

Type f1 <enter> to get help+info
time    ns      dac     temp    status  diff_ns filtX10 tc      filt    timer1  temp1
1       Missing 10MHz?  32768   25.8    WarmUp  1013    10230   32      1       46291   239     Five minute averages: TIC+DAC+temp
1       Missing 10MHz?  32768   25.9    WarmUp  0       10230   32      1       41521   238     Now acquiring value: 0
1       Missing 10MHz?  32768   25.9    WarmUp  0       10230   32      1       6677    237
1       Missing 10MHz?  32768   25.8    WarmUp  0       10230   32      1       41333   240     0       0       0       0.0
1       Missing 10MHz?  32768   25.7    WarmUp  0       10230   32      1       34487   240     1       0       0       0.0
1       Missing 10MHz?  32768   25.9    WarmUp  0       10230   32      1       6018    239     2       0       0       0.0
1       Missing 10MHz?  32768   25.7    WarmUp  0       10230   32      1       27025   241     3       0       0       0.0
1       Missing 10MHz?  32768   25.8    WarmUp  0       10230   32      1       40620   238     4       0       0       0.0

6

General Technical Chat / Re: H5N1 bird flu and how we're risking another global pandemic

« Last post by Zero999 on Today at 04:01:37 pm »

There's no need for a pandemic. Current farming practices are sustainable, because population grow will come to a halt and reverse, within the next few decades. The fact our current economic system relies on population growth is a problem and will eventually collapse, due to a lack of new workers and too many pensioners.

7

Microcontrollers / Re: primitive serial CLI / Console for embedded systems - Ideas for implementation?

« Last post by tooki on Today at 04:00:00 pm »

https://interrupt.memfault.com/blog/firmware-shell

That is the code I started from to develop the CLI for a piece of lab equipment I built.

The use case is practically identical to yours: human use for development, but ultimately controlled by Python scripting for experiment automation.

In my case (a 6-channel capacitance meter built around Smartec’s UTI chip, with a PIC microcontroller to read the UTI’s weird period-modulated output and communicate over RS-422), I made some settings “modes” (verbose on/off, debug on/off, echo on/off, and fast/slow mode) that persist between measurements, while others are per-call, like the channel and number of measurements.

For example, “read 1 20” takes 20 sequential readings of channel 1 and returns them as a list, while “avg 1 20” takes 20 sequential readings of channel 1 and returns a single averaged value. In debug mode, the result includes statistics. Verbose mode outputs the units (pF), extra human-friendly info, and line numbers on lists. The idea is that in automated operation, echo, debug, and verbose are off and the unit returns bare numbers that are easy to parse.

I also added single-letter “aliases” of the commands, so that the two examples above can be typed as “r 1 20” and “a 1 20”, respectively.

The mode commands accept a Boolean value (true/false, t/f, 1/0, and on/off are all accepted), but function as a toggle if no value is passed. This allows the control script to positivity set a known configuration before sending commands. One of the things the CLI parser returns is the number of arguments received (including the command itself), so you can easily make your command handler do different things depending on the number of arguments.

Oh yeah, and I added backspace support (quite handy for us humans).

8

Projects, Designs, and Technical Stuff / Re: (Yet Another) DIY Multislope ADC

« Last post by Kleinstein on Today at 03:57:39 pm »

I would not go for just a crystal, as the frequency can be effected by the µC and this can cause nasty INL problems.
There are relatively cheap boxed oscillators that can do the job (some 1 ps jitter specs seem to common).
The question is if one needs external latches / flip flops for an extra sync. step. The extra external sync step may reduce the jitter a little and reduce possible delay modulations at the µC, but it also adds power consumption and possibly EMI problems. There is a good chance that one could skip it.
With an external sync one would likely use a relatively low clock (like 12 MHz), which should make the USB use easy.
Without an external sync one may opt for a faster clock (maybe 48 MHz if one wants USB while the ADC is active).
For the processing power already 12 MHz should be sufficient. A DMM would anyway have a 2nd µC at the output / interface side.

9

Test Equipment / Re: Choosing between entry-level 12-bit DSOs

« Last post by Antonio90 on Today at 03:57:22 pm »

comical or not, professional or not, sds800x cannot see 400-500MHz even on one channel active, prove me wrong.

🤣🤣🤣 I don't need to. The FACT of REALITY is that if you're trying to measure outside of the scopes designed bandwidth, then the results simply won't be accepted by any professional. The results shapirus showed of his DHO800 measuring 500MHz were TERRIBLE. If you think that's something to be proud about, I don't know what to tell you.

Do you need to measure a 500MHz signal? Your scope better be CERTIFIED to do so, or you could be subject to legal action when the product you're trying to sell doesn't meet specs, or the device you certified as functional isn't. Standards and reality matter, unless you're talking about a toy.

Are you looking for a toy or a tool?

Your scope will not be "certified" whatever that means when out of cal either, and I bet most, if not all of your equipment is not calibrated regularly.
Certainly mine isn't, and I intend that to stay that way.

I couldn't care less about 500MHz signals right now, which doesn't mean being able to visualize that signal is completely useless for everybody. Very few people buy either of the scopes discussed in this thread for certification and measurements in which legal liability is involved, and nobody without periodic calibration.

Let's keep the discussion where it belongs. I do agree that the SDS800X-HD is a better oscilloscope overall. I can also see why, for basic use, the DHO800 can be more than enough and in that case in particular it might be a better purchase due to some usability and convenience advantages.

That being said, I just got my SDS800X-HD. I'm thinking of buying a DHO800 just to compare them thoroughly, but it's a bit of an expensive thought.

10

Projects, Designs, and Technical Stuff / Re: Build or buy? Multi-level vessel temperature logger

« Last post by paulca on Today at 03:56:15 pm »

Yea, then it only has a "Request a quote" button, it's too expensive.

Interesting.  So for the DIY approach, a silicon or stainless tube. 

8mm ID (which I have) will just about take a TO-92, so it will take DB8120b 'one wire' senors, requiring only a pair of wires for the whole "bus" of sensors.

I can probably very easily layout the apparatus without any PCB needed.  "Pull it through" the pipe/tube and then, gravity fill the tube with epoxy.

The only bit that sounds like it will go wrong is the last part.  I don't have any thing resembling a vacuum to pull the expoxy (or silicon sealer) through.  Not unless I get really runny, designed for the purpose epoxy.

EDIT:  I also need to make sure the epoxy (and everything) is okay at 105C.

What if I filled it instead with something liquid, non-conductive and then expoy shut the two ends?  (Can you solder shut stainless with hot air?)  How runny is "potting" compound?