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1
Test Equipment / Re: Brand new BM869s or used Fluke 287?
« Last post by rsjsouza on Today at 02:54:26 AM »
I have a U1273A and its continuity is pretty good, including some additional interesting features I highlight on the video below:
2
General Chat / Re: Return of 502- Bad gateway Error
« Last post by WastelandTek on Today at 02:53:45 AM »
briefly here also, not like before though
3
Beginners / Re: z wave protocol
« Last post by hermit on Today at 02:53:35 AM »
If he didn't understand the closed nature of the protocol then he's really in over his head ( http://www.thehindubusinessline.com/info-tech/95-engineers-in-india-unfit-for-software-development-jobs-study/article9652211.ece ) or hinting for some kind of cracked/pirate version.

I get the impression this is an attempt at being entrepreneurial and thinking someone on the internet is going to do all the work for you. 

4
Beginners / Re: z wave protocol
« Last post by free_electron on Today at 02:53:19 AM »
open stack ? There is no such thing as free sauce in z-wave.
Sign the NDA , use the precompiled libraries and off you go. the z-wave protocol is closed and secret.
Even witht he NDA signed they will not disclose how the routing etc works. you get a precompiled library and an API. the z-wave stack is not available in source form.

It contains a number of features not found in zigbee (where everyone just farts around and doesn't give a rats ass about interoperability with someone else's products ).

Your product needs approval to get it on the market. simply to guarantee it will play nice with the other devices .

Like i said : i have a z-wave system in my house. Setup is real simple. Click the 'learn' button on the dongle , press the button on the device and they are now paired. the system is a mesh network that is self learning and self routing. i can send commands from a master to a slave (actuator device) , or 'pair' a controller to a slave device. The beauty of z-wave is that there is no master controller required. Most domotics system bank on a central controller. if that controller dies, crashes, explodes or whatever the entire system stops working. Z-wave doesnt have that problem. if a node dies , only that node is dead. the rest keeps functioning as intended.

oh, and z-wave is not french ( i don;t know where you got that ...) it comes from the scandinavian countries. denmark i believe )
5
Repair / Re: 11301 - basic analog scope troubleshooting help needed
« Last post by WastelandTek on Today at 02:52:17 AM »
...with all the covers on but ...

man Jerry, just like my comment in the other thread, when I had behaviors like this it ended up being RF in the shack, what are you using for lights in there?
6
Move the resistor & LEDs to between the 12v & drain, not the source & GND.
7
Manufacturing & Assembly / squeegee repair
« Last post by ar__systems on Today at 02:49:50 AM »
I got a used stencil printer, and I think I need to do something with the metal squeegees: the edges are kind of rough. I tried to run it over stencil and it catches on the apertures. I'm thinking to polish them a bit with sandpaper or... any other suggestions?



8
Test Equipment / Re: History of "Weinschel" companies?
« Last post by MichaelBrenden on Today at 02:49:45 AM »
DC area is littered with mil-ind companies...maybe 75% of the area's residents are employed by fed gov and related.  Watkins-Johnson was one, right across the street from NBS (now NIST), maker of microwave and other spy tech.

For lots more, but west-coast, see Secret History of Silicon Valley youtube.
http://www.youtube.com/results?search_query=secret+history+silicon+valley

Wash Post article 1983 has some info
https://www.washingtonpost.com/archive/business/1983/05/02/manufacturing/82d2f01f-bc4b-4f4e-ae3b-07c0f2c0b961
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It shows 0,295€ for me, 30 cents for a programmable micro is pretty cheap, beats a timer with passives all around to set it up.
10
In an earlier thread I mentioned I was trying to remember how to use a transistor, and this is what I was planning for it.

In the test circuit I'm using a voltage divider and feeding 6v from my main power supply.  But I've also tested the circuit using a LabJack controller to feed 5v into the 555.  The test lights are a series of little LEDs powered by 12v, but eventually I'll want to power much larger lights (hence the use of big beefy transistors).   I ended up buying some IRLB8721PbF (https://www.infineon.com/dgdl/irlb8721pbf.pdf?fileId=5546d462533600a40153566056732591) and RFD14N05L (https://www.fairchildsemi.com/datasheets/RF/RFD14N05LSM.pdf) transistors.  Both claim high power capability, and can be driven by ~5v at the gate.  I know they're probably overkill, but I wanted powerful ones in case I want to use them for a more powerful project one day.

I must be doing something wrong though, the 555 is outputing a clear square wave that goes from 0 to 4.5v, but it's not activating the transistor properly.  Using either of the transistors, I end up seeing 3.4 to 3.8 volts at the source pin.   Either using the voltage divider or the controller, it's just not working.  I tested the lights using an ampmeter and the 12v source directly to see how much resistance I should put on them.  1.5 Kohms had them use 3 mA, which seemed decently bright.  Using a single LED, giving it more current than that caused it to burn.   So I don't think that the LEDs would cause any problems with the transistor, but that's the only thing that I can think of.  Am I missing something obvious?
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