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Eggi
Eggi
06:31
Hi guys,
Can you help me with designing a current measurement circuit?
I have a coil with around 100 Ohm, inductance is not known yet, but later on and i had a look at this: http://cds.linear.com/docs/en/datasheet/1366fb.pdf
The sense resistor would be a 30mOhms 1W resistor.
So at 450mAmps (made some measurements, this was the max. current) i have 13,5mV.
The slew rate of the OPAmp is sufficent.
What are things I have to be aware of? The input capacitance of the OPAmp so that i don't hit resonance frequency?
 
2 hours later…
Asmyldof
Asmyldof
08:55
@Eggi In stead of buying a $3.8 op-amp that's over-specced, just buy a current measurement amplifier, like the $0.7 On-Semi NCS199A series
Eggi
Eggi
09:44
Thank you.
Do you see any problems with measuring the coil? The GND Potential of the coil and the op-amp are the same.
 
7 hours later…
Asmyldof
Asmyldof
17:09
@Eggi Just the 50V
 
2 hours later…
PlasmaHH
PlasmaHH
19:35
In the magnetic stirrers that work by rotating a magnet, what would possibly be a good magnet material for a strong magnet? the classic neodymium supermagnets don't seem to be feasible
 
2 hours later…
Micah
Micah
21:06
Has anyone used a development board that breaks out the USB 3.0 pins from a minicard? Similar to this link, except I need it to be USB 3.0 amazon.com/USBMA-Module-V1-2-Wireless-Adapter/dp/B00B2P9KOO
The Photon
The Photon
@Micah What are you trying to do? USB 3 (Super Speed) is pretty fussy, and breaking out the pins would not normally be a good idea.
Micah
Micah
I have a Terrestrial modem card from Sierra Wireless that uses 3.0 or 2.0 I need to be able to test the speed differences in my system.
PlasmaHH
PlasmaHH
does not yet sound like a proper reason to break out the pins
Micah
Micah
I have no other way to connect the 3.0 to my system. I don't need to actually breakout the pins, but I need a 3.0 connector from the TM development board
just like in the link I sent, except that is 2.0
PlasmaHH
PlasmaHH
usb 3 seems to have some standardized connectors...
Micah
Micah
21:13
yes, what do you mean?
PlasmaHH
PlasmaHH
so you have two usb 3 devices that you want to connect... why not use a usb3 cable..?
Micah
Micah
no
I have a TM card from sierra wireless techship.com/products/sierra-wireless-mc7455-lte-cat6/…
I need access to the USB 3.0 interface on that chipset. There is a development board that breaks out the USB 2.0 interface, but I am looking for one that breaks out the 3.0 interface so I can connect it to my system
Like I said earlier, something like this but with a 3.0 connector amazon.com/USBMA-Module-V1-2-Wireless-Adapter/dp/B00B2P9KOO
and by 'breaks out' I mean into a connector on the edge of the board
PlasmaHH
PlasmaHH
So a mini card to usb3 adapter really...
Asmyldof
Asmyldof
@PlasmaHH meh?
PlasmaHH
PlasmaHH
@Asmyldof might need a replacement
Asmyldof
Asmyldof
21:21
meh
PlasmaHH
PlasmaHH
gnnn
Asmyldof
Asmyldof
blipfm
PlasmaHH
PlasmaHH
tksss
@Micah if anyone then aliexpress has it, but since those seem to be useful for development purposes only it seems to not be likely to have it commonly be available in usb3
Skyler
Skyler
22:04
Hey guys, I'm in a lab and we have a new arduino board (WEMOS LOLIN32), which has the capability but lacks support for BLE handshakes so far in arduino (and my supervisor doesnt want us to abandon this codebase or wait til they release it themselves since its gating other development), and I've been tasked with trying to find a cheap programmer (like India/China cheap) to write the handshake library for us. Any recommendations on where to get started?
The Photon
The Photon
@Skyler The Arduino stackexchange chat will probably give better answers on this (even if there hasn't been any activity there for 5 days).
@Micah Are you sure it uses USB 3.0? Or is it just compatible with USB 3.0 because USB 3.0 hosts must also support all USB 2.0 capabilities?
@Micah Also, USB 3.0 uses 4 totally new pins/wires for carrying SuperSpeed signals. If you see a signal on those wires, then it's using SuperSpeed. To use High Speed or Full Speed it would continue to use the old DP/DM pins.
Now, a 2-3 GHz scope probe for checking those wires might not be sitting around every lab.
Skyler
Skyler
@ThePhoton yea, the lack of activity was the sad part, and i figure the procedure is pretty comparable for you guys with other electronic firmware (or kind of firmware)
The Photon
The Photon
@Skyler Sure, but things like "BLE handshake" are totally meaningless to me.
Skyler
Skyler
low energy bluetooth
The Photon
The Photon
Hey, two people in one day posting because their kitchen appliances are talking to them and controlling their brains. Is that some kind of record?
Skyler
Skyler
22:20
must be cross-talk in the brain controlling waves
The Photon
The Photon
@Skyler Maybe I've got the gain turned up too high on this thing...
Asmyldof
Asmyldof
@Skyler I would not even spend half a second thinking about outsourcing to a far away country, where I have no real control or influence something as vital as firmware or even electronic design
Shalvenay
Shalvenay
@Skyler LOL
hey there @ThePhoton and @Asmyldof
Asmyldof
Asmyldof
Almost good night though
Unless you're about to tell me you'll accept an ACH payment and make that a wire transfer to a BoA account fully free of charge, while under contract
The Photon
The Photon
22:40
@Asmyldof What does your fridge think you should do?
Asmyldof
Asmyldof
@ThePhoton Feed it more vegetables?
And for some reason randomly kidnap and torture people
Skyler
Skyler
@Asmyldof eventually the board fab will release the right things, I just need something to interface with in the mean time to continue development
@Shalvenay hey shal
how you doin
Shalvenay
Shalvenay
alright here?
Skyler
Skyler
last time we talked was the playtest i think
howd that campaign go
Shalvenay
Shalvenay
OK
Skyler
Skyler
23:18
well. ok
=P
im trying a funky multiclass for one campaign
hows 1 fighter/1 sorcerer/18 tempest cleric sound to you
Shalvenay
Shalvenay
23:32
makes sense to me, bit palahack ish

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