So, I'm trying to connect two devices that communicate over J1708 to eachother. One device has a female DB9 port, and the other end has a female terminal block connector with three spots for pins. The cable only needs to have three specific pins connected. Where's the best place for me to purchase one of these? Thanks!
Actually, I really need several hundred of these.
Because there are actually several hundred pairs of devices.
@DrewBuglione I'm going to say, buy some cables terminated with DB9 at both ends, twice the length you need, and cut them in half to get the exposed wires for connection to the terminal blocks. On the other hand, for hundreds of units you ought to be able to find someone who will do a custom assembly with the connector on one end only for a reasonable price.
@ThePhoton That was an idea I had, too, but then I'd have to worry about which wires went to which pins on what side, and it won't just be installing these.
@DrewBuglione Hopefully they wire them all the same, so you only have to ohm it out once to figure out which color wire goes to which pin...but you're right there is some risk there.
@DrewBuglione Sorry, no. I don't even really know what Jwhazzit is.
@PeterJ chat.stackexchange.com/transcript/message/8825863#8825863 Thanks for the link :) - As long as it works to protect my pc if 12v, mains comes rushing down the wrong pin, I'm fine with it. I wish it had normal USB A on both sides.
In previous version of Arduino the limiting 8-bit microcontroller board it seems that implementing HTTPS (not merely HTTP) was almost impossible. But the newer version of Arduino Due provides 32-bit ARM core - see spec here.
I tried to check several network libraries (libcurl, openssl, yaSSL), b...
@angelatlarge Here in India, I can get Arduino Nano boards (from China via eBay) way cheaper than I can get the ATmega328 ICs. I have about a half dozen different Arduino clones from the nano to the Mega, but not the Due.
@angelatlarge Shenzen, China. The Nano is brilliant - nice bread-board friendly row spacing of the pins, fits onto the little 1 inch square mini breadboards too, has USB, the Meduino Nano Enhanced which I favor even does 5 Volt and 3.3 Volt operation by a switch, and they can be as cheap as $3 if you bid carefully.
@angelatlarge Not the Meduino, there are several versions of those.. the Meduino Nano Enhanced. It's also one of the better construction quality clones I've used.
@angelatlarge My target audience consists of workshop attendees who are newcomers to anything electronic or software... The InduinoX is really tough to damage (see their videos of hosing it with water while it is running, and dropping it from heights, etc), plus it comes with a bunch of different hobby-friendly peripherals built into the board
- IR LED, Chopped-IR TSOP sensor, RGB LED, couple of other user LEDs, user pushbuttons, and all connected via jumper blocks so each can be disconnected from the base device.
@angelatlarge Ref your comment on "cheap chinese SSRs"... You can actually get really cheap genuine Omron SSRs on eBay.com, that's the way I would go. I've bought some and Omron India confirmed they are genuine, at only one tenth the price in India.
@AnindoGhosh BTW, nothing against cheap or Chinese: I buy both (in combination and not) all the time. I just head that the SSRs can be bad, and given that this is line, seems like could be important.
@angelatlarge Sure. And yes, that part would work.
My considerations for relays etc - I prefer sellers who show multiple views of a product, and I look carefully at the printing quality - a fake would typically be a reprint consisting of an overprint increasing the part rating.
@angelatlarge that is a knock-off and stated as such. I stay with Omron branded ones, the company is extremely aggressive at policing fakes on eBay. Also, I believe they are a Chinese company, a powerful and influential one at that - so they might conceivably be sending goons to the door of fake-sellers.
@W5VO Yeah, tell me if you can't tell me. It says "3 comments flagged" - can you tell me what I am getting flagged for? Please don't tell me who is flagging (it might not show you anyway), but what kind of comments of mine should I moderate? Too chatty? Being an ass? Should I not worry about it?
pretty much every flag requires human intervention - the only exception is the spam/offensive flag. Again, you have to be doing something really stupid for a no-warning smackdown.
@AnindoGhosh I haven't done the math, but with a 35 mV (RMS?) input and a gain of 200...I don't think it's possible to get a 7 volt swing out of a single JFET amp with any reasonable combination of JFET currents and load resistors.
of course, the power supply voltage isn't specified.
I remember someplace doing an exercise, (I think it was AoE) to find the maximum voltage gain you could get out of a common emitter bipolar amp with a resistive load and I don't recall it being anywhere near 200; something similar applies to jfets
My oscilloscope has gone for calibration, otherwise it would be interesting to run a PWM into the 2222 and see where it explodes.
@angelatlarge No, I'll stay with my SugarFree, two please.
@angelatlarge I'm the specialist on destructive testing of components on this site. See if you can find my answer where I blew up a dozen LEDs to determine what point they die at.
@AnindoGhosh Too late. You got another heads up in my answer.
@AnindoGhosh No links to your house this time.
@AnindoGhosh But the last guy, he is hatching reptiles. So if he comes to live with you (after his house burns down), he will not be alone. I hope you like snakes, lizzards, salamanders, and iguanas.
@Bitrex Sorry, I think I was unclear on my question... I meant, why is there a concern with the gain of 200 question, i.e. are you flagging that question or something. I realized afterwards that you meant to point out the nasty answer, not the question itself.
@angelatlarge You know, if you were going to edit your question anyway, you should have improved it by mentioning that the 3.7 Volt probably implies a LiPo, which would work fine. Use the wisdom gathered in chat, to appear wise on the answer :-D
@angelatlarge Actually I kicked it. Then I took it with me to the ER. They thought I was looking for a vet, all I wanted was an ID on whether the snake was poisonous.
I recall the hospital folk were rather rude, especially after one of their staff fainted on seeing the snake.
@angelatlarge No. Just around when they told me they don't treat dead snakes, the hospital boss doctor arrived to see what the ruckus was about. He turned out to be a doctor who had treated me before (for a motorcycle accident). So all ended well.
@angelatlarge I'm not bothered about credit, I just like answers to have lasting value. This one would make sense to future researchers seeing an apparently arbitrary 3.7 Volt somewhere... ah ha! That must be a LiPo!
@angelatlarge Well, the sodden basement place I rented just after college, there was a forest patch nearby with longer snakes, and supposedly lethal ones too.
@W5VO That neighborhood of my youth, yes. Current neighborhood, the only non-human animal life other than rats and cockroaches that you can find within a few miles, wears a collar.
I wonder if people use collars on pet snakes.
@angelatlarge Good catch there. At least until the code hangs on an on state. :-)
@jippie Those examples are just to get you started.
@jippie And yes, that I've noticed as well. However, if you follow the lab workbook for Stellaris, everything in that book, including every example, is working for me.
This is my first question, and I'm pretty new to the world of electronics, although I'm attending an Australian college course called "certificate 3 in electrotechnology".
My guitar tuner seems to have a ground problem. I think it's from the battery terminal, as it was fine but then 9V got stuck...
@AnindoGhosh Hmmm.. that's not what I think of when people say "in that case the entire point is moot". I think debatable wouldn't fit there very well. It's say "irrelevant" or something.
@angelatlarge Only for ISRs where default compiler optimizations sucked for my purposes. The pushes, pops, etc, I didn't need many of those because my ISR code merely set one flag in memory and returned. A frequent situation.
@angelatlarge No, it isn't a synonym. Those are two divergent usages of the same word. English is very contextual as a grammar. That's why English NLP is very challenging to design.
@angelatlarge In general, if you expect 200% improvement by going ASM, you either have really crappy (for the embedded world) highly call-within-call-within-call code, or you are using some crap high level libraries.
@AnindoGhosh "Coding parts in assembler may greatly improve performance, especially when it comes to bit-wise operations by taking full advantage of all flags in the SREG" - Hanno Binder
@angelatlarge the code that gcc spits out is pretty well optimized. The major gain you can get is by optimizing order of instructions, and with that eg. optimizing the moment a register is read.
@angelatlarge start by just peeking into the generated assembly listing when you compiled a program, that is giving very much insight and on the side you get familiar with the instructions.
@angelatlarge The big savings are in function calls, and by removing generic checks and measures that may not be needed in your particular application. Anything else, diminishing returns.
And here's the biggest secret - Need 10% more? Change your crystal.
@angelatlarge Actually don't even consider a processor change, before using a profiler on the code first. For all you know, one bad function call might be all that needs fixing.
@angelatlarge stat of play = what is happening (or not happening) as it should (or shouldn't). :-)
@jippie Some of us find it tough enough to deal with problems that are in front of us, and you even keep backup problems in case the main ones get solved?
@AnindoGhosh Tried every optimization I could think of - couldn't unroll everything without running out of flash, but I've hit the wall with the C code
@AnindoGhosh That depends. Right now the thing runs at 210% of what it should run at. But in the worst case I am OK with using shuffling half the data out, so yeah, 10% or so.
It would be nice to get all the data out. But I am ok with giving up on that.
@angelatlarge Then just try re-clocking with a faster crystal if your MCU can take it... Next step, move up one step in the same processor family. Those are the simplest most practical options.
@angelatlarge Might want to reconsider that, but that's a different issue. So hold on, have you seen the blog about the guy who got some amazing oscilloscope performance out of an arduino based scope? He's shared all his sampling speed and data shoveling tricks.
@jippie OK, let me know when you have a microcontroller based 2-channel transimpedance amplifier for picoamp range :-) Till then I'll stay with my choices.
@abdullahkahraman The jelly bean application discussion was separate (my CA3240 works for that BTW) and the "digital is better than a quad op-amp" discussion was a different one. Don't worry, we oldies talk in tongues.
@abdullah: see i have to find maximum cable length in feet as output...my input i have 2amp current, singlephase, 120volt 14awg wiresize and metal is copper
Okie @jippie and @abdullahkahraman I need some advice: I have 3 unused slots in a sampling order from TI. I'm specifically working on some ultra low current transimpedance stuff, and I think I have that covered with a femtoampere op-amp and a optosensor with integrated transimpedance amp. What do I fill the remaining 3 slots with, that might actually be useful, rather than toys?
"My jellybean RRIO quad op-amp is the AD8044." , " @AnindoGhosh I use a microcontroller for that." , "@jippie For quad op-amps? or for counting jelly beans?"
@Bitrex That's what's strange about the electronics component retail market in India. Some common parts are just not available, others are sold at 10x to even 20x the Digikey price, and yet others are at a one tenth of Digikey prices.
@Bitrex Sourcing is typically via undervalued container loads, direct from the fab locations in Malaysia, China etc... So high volume products get here at barely the shipping cost. Low volume products, the local vendors order in small quantities, and then charge insane mark-ups
@Bitrex The CA3240 became very popular locally about 6 years ago, so it sells cheaper than any other dual op-amp you can find here. Yet its specs are better than many others (not counting RRIOs)
@Bitrex I will have to ask when I next go to the electronics street.
@AnindoGhosh I think I have some in my bin, I bought a big sampler lot of various op amps from that Tayda Electronics outfit a while back. I haven't had a chance to use that one yet.
