Recent Posts

1

Test Equipment / Re: Vevor SDS1104 for first oscilloscope?

« Last post by MadFlower on Today at 12:40:45 am »

It looked like a rebadged owon or hantek and from other reviews those do gives full advertised bandwidth. , It does have usb scpi and record capturing to the computer for analysis with labview. It does not have some of the nicer features ON the scope itself. I assume program some other functions and triggers via scpi I believe it is only an 8-bit adc so that might be more of a limit, then anything.

It is one sale for 150 bucks right now which is what a poster above said it was worth. but it is the only one in that price-range with bandwidth =and= sampling rates.  I think I am going to order one as my first scope. I have heard too many Weller vs Hakko soldering station debates, and fluke vs everyone else, and if  you are doing professional level work, I would recommend a higher end scope, soldering iron, etc.  but for a hobbyist, you can probably make this work for most things, and if you get to the level where it doesn't work, you are probably no longer a hobbyist and the budget will be slightly larger.

The hooks to external software are what is the most intriguing to me. I didn't look for SPI but labview will capture CANbus messaging so I assume it will capture SPI and i2c messages as well and it may require some elbow grease to get it to work right that is software built into other scopes.

2

Mechanical & Automation Engineering / High density connector troubleshooting

« Last post by mtwieg on Today at 12:38:17 am »

I'm working on a produce with a backplane and a daughtercard which connect with a very high density connector similar to this one. We apparently have some alignment issues, as we often get bent/broken pins if we are not very careful when mating the daughter card. But we cannot determine what the alignment error is.

I'm wondering if someone knows a trick for determining what parts of the connectors make contact first when mating. In the past I've seen mechanical engineers check for contact/interference with special paper which leaves visible markings where contact occurs, sort of how dentists use articulating paper to check where teeth contact each other. But I don't know what this stuff was called, and I'm not sure it would be suitable for this purpose (I don't want to ruin the connector, I'm hoping whatever this stuff is can be cleaned).

Anybody know what I'm referring to?

3

Projects, Designs, and Technical Stuff / Re: MCU recommendations- looking for low pin count with more memory than ATtiny

« Last post by Sacodepatatas on Today at 12:27:29 am »

The STM32G030 is well suited for the task. Maybe a bit overkill, but it is very cheap (around 35-40 cents) and well supported. However if you are going to produce thousands of units, you might consider even cheaper contenders that, although not as powerful as the STM32G0x, will also do the job. The CH32V003J4M6 is a RISC-V MCU made by WCH that costs below 20 cents, but you need to purchase a cheap dedicated debug probe (around 4€). There are tons of code examples and many people supporting these chips. Another MCU for considering is the PY32F002AL15S6, you can use any CMSIS-DAP probe you could already have or make (as with the STM32G030, because both are Cortex M0+), and it costs around 10 cents in low quantities, but it is not as well documented as the formers.

4

Projects, Designs, and Technical Stuff / Re: Duty cycle and frequency to drive LED for best energy efficiency

« Last post by David Hess on Today at 12:25:05 am »

The LED has a maximum efficiency at a specific current.  Highest efficiency at lower brightness means chopping the signal while operating at this relatively high current.

5

Computers / Re: Australian Government Invests $1BN on Aussie Quantum Computing Startup

« Last post by Bud on Today at 12:23:29 am »

Australia will invest $940 million in Silicon Valley start-up PsiQuantum in a major bet that it will build the world’s first commercially useful quantum computer in Brisbane.

Is there any evidence of a quantum computer doing anything better than a traditional computer, or is it just all theoretical?

According to my world leading quantum computing research friend, head of a quantum computing lab, nope, they aren't capable of anything practical yet.

That implies that either that Psi thing is going to beat IBM, or Australian government is incredibly stupid. And I am not sure about the former.

6

Projects, Designs, and Technical Stuff / Re: Brinking Light pattern for maximum attention distance at night

« Last post by BrianHG on Today at 12:19:06 am »

When I follow the link to youtube I see an 240000 lm output for 8000W lamp. That is only 30lm/Watt.

White LED lighting can get 200lm per Watt. Green led's can have a higher light output per Watt.

Ok, how many expensive 5w green led can you cram into a single point to attain a 240,000 lm pulse?
120 5watt leds?  We aren't talking about the 1watt leds.
Concentrated into a tiny package.
Luckily with such a low duty cycle, you might not need any heat sink.

Optics and packages for a huge 100watt spot led (usually made with smaller segments) can be purchased, circuit designed and manufactured.  It will take a lot of work as you want a 100watt current regulated pulse, but don't need the continuous constant power output if you want this device to run off of 2-4 batteries.

If you want continuous output, think along the lines of those DIY insane bright LED flashlights.  Your looking for a pulsed version of those where the pulse length will be around 0.1 or 0.05 seconds for human eye visual brightness instead of the less than 0.0001 second pulse of a xenon camera pulse.

7

Embedded Computing / Graphical Calculators running basic

« Last post by simon christo on Today at 12:18:29 am »

Hi there!!
What's the story, on Grahical Calcultors.Im thinking on purchasing one, and I'm not sure, which one to buy??
Tah, Simon.

8

Test Equipment / Re: New 12bit 500MHz Micsig scope WITH knobs [Mic-OPI] MHO5004-12bit / MDO5004-8bit

« Last post by egonotto on Today at 12:17:25 am »

Hello,

Dave's video about the SDS1000X HD prompted me to test the noise of MHO3 at comparable settings.

Best regards
egonotto

9

Beginners / Re: LM199 10V reference

« Last post by David Hess on Today at 12:16:21 am »

Do I need to swat the opamp with something better?

The OP177 is more than good enough, so there is not much to be gained with anything better.  Drift and noise are dominated by the reference.

The performance of the operational amplifier can be improved by buffering its output to remove load from its output.  This will improve load regulation and open loop gain.  The buffer could be a transistor in class-a, class-ab diamond buffer, or another faster and higher current operational amplifier.

10

Networking & Wireless / Network attached usb hub

« Last post by PinheadBE on Today at 12:14:19 am »

I have plenty of external hdd.   I woukd like to make them available on my intranet as shared drives accessible from all multiple windows and linux  PC,s android devices.  no need for raid functions , but if it is available, itsok

So, it must be plugged in my router rj45 plug, and provide 4 or more usb ports

Preferably off-the-shelf and affordable for an hobbyist

Any suggestions?