Recent Posts

1

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

« Last post by IanB on Today at 09:08:47 pm »

You might want to plug the device into a Kill-A-Watt and measure the power consumption under full load. I suspect it won't be more than 1000 W, but this way you can measure it and find out.

2

Test Equipment / Re: Using SCPI with python via telnet to connect with a siglent scope

« Last post by eTobey on Today at 09:07:58 pm »

your kommando function doesn't just send the command to the scope, it also returns the first reply by running self.lese_daten().

You're not doing anything with the data the kommando function returns.

This is actually not my kommando ;-). Just got that from the internet, and did not notice this. Should have actually looked more closer there. 

Thank you 

3

Dodgy Technology / Re: KCD-11 rocker switch from aliexpress is junk

« Last post by thm_w on Today at 09:03:38 pm »

The thing is some suppliers with the exact same looking part might be great. But yeah these look cheap.

LCSC has some from 10c each that I'd probably trust more: https://www.lcsc.com/product-detail/span-style-background-color-ff0-Rocker-span-Switches_SHOU-HAN-KCD11-2P-R_C5884414.html (hundreds of options just picked the first one).

4

Other Equipment & Products / Re: Different bases on Amscope microscope

« Last post by KE5FX on Today at 09:03:05 pm »

Any time you bump them the microscope shakes for ages.

So don't do that.

5

Test Equipment / Re: Siglent SDS3000X HD and upgraded SDS1000X HD

« Last post by Martin72 on Today at 09:01:41 pm »

Speaking of scope music, I tried it briefly earlier....With ERES 16bit it's pretty cool.
I have to work through next weekend, maybe I'll have more time for scope the following weekend.
But I took a few pictures earlier and tried out the scope music briefly.
What is noticeable so far is the very short reaction time when working through the menus.
Makes me want to try out more.

6

Beginners / Re: Replacing SRAM IC with Flash

« Last post by xvr on Today at 09:00:07 pm »

Do not forget to add series diode to battery - lithium battery do not like when someone trying to charge it. They could blow up.

7

Test Equipment / Re: Using SCPI with python via telnet to connect with a siglent scope

« Last post by XiMMiX on Today at 08:54:54 pm »

your kommando function doesn't just send the command to the scope, it also returns the first reply by running self.lese_daten().
You're not doing anything with the data the kommando function returns.

8

Beginners / Resistor ????

« Last post by K.primdahl.8270 on Today at 08:54:12 pm »

I'm puzzled by this resistor
Can anyone help please

9

RF, Microwave, Ham Radio / Re: Quansheng UV-K5(8) firmware modding

« Last post by radiolistener on Today at 08:53:21 pm »

I backupped old fw of my K5.

How?

According to source code research, I can backup entire EEPROM with this command:

Code: [Select]

./k5prog -r -v
it reads 8192 (0x2000) bytes, the last 512 (0x200) contains calibration data.

At offset 0x1F40 there are 8 uint16_t values which define battery indicator values:

Code: [Select]

[0] - 0 bar value
[1] - 1 bar value
[2] - 2 bar value
[3] - 3 bar value it equals to ADC value for 7.6 V
[4] - 4 bar value
[5] - always 0x2300 ???
[6] - always 0xFFFF ???
[7] - always 0xFFFF ???
The battery voltage can be calculated as V = (760 * ADC) / [3] / 100



And I can write new firmware to the radio with this command:

Code: [Select]

./k5prog -F -YYY -b firmware.bin
Still looking for a way to get current firmware from the radio

10

Beginners / Re: Replacing SRAM IC with Flash

« Last post by SiliconWizard on Today at 08:48:43 pm »

How about using 512k×8 low-power SRAM like CY62148ESL-55ZAXI, and controlling the four highest address bits (A15, A16, A17, A18) with a 16-position absolute encoder and four pull-up resistors?  With a pull-up on /CE, the stand-by current draw is just 2.5µA typical, max. 7µA, and voltage can be 2.2V–3.6V or 4.5V–5.5V.  That is, you can use 2.2V – 3.6V battery backup voltage.   Since LH52256C/CH uses 5V logic, the battery vs. normal operation voltage selection should be easy (higher voltage wins)

Actually, this is "better" than this. As usual with SRAM, the min. data retention voltage is much lower than its operating voltage range and the current is also much lower in practice.
The datasheet states 1.5V min for data retention. So yes, a typical CR2032 lithium battery would last a very long time and you'll get more out of it than the typical 200mAh which is given for a cutoff voltage way above 1.5V.
Add a largish cap in parallel with it, and you'll also have ample time to replace the battery when it's completely discharged, without losing any data.