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I switched over to a 555 set up as a monostable multivibrator and at the recommendation of a coworker tried a PIN photodiode as a sensor for test purposes and everything works! Like holy poo poo the PIN photodiode is sensitive as balls, I can pop a camera flash in the next room over and it will pick it up.
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Aug 19, 2018 21:28
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I'm super loving green when it comes to wires and burns, but here goes. I want to use some spare pc case fans I've got kicking around for a non-pc project. These are some lovely 12v 160mA fans I've got on hand. So, am I hosed in my understanding, or can I just find a 12v 1A power supply from my local pawn shop bin and splice/solder/knot a pair of these fans to that? In parallel to the salvaged plug so they get equal voltage? Am I going to burn down my house?
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Aug 20, 2018 02:35
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Yeah if you wire them all in parallel, then as long as you supply the correct voltage, and your power supply is capable of outputting at least the sum of the load currents, it will work.
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Aug 20, 2018 03:00
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RedChesterfield posted:I'm super loving green when it comes to wires and burns, but here goes. I want to use some spare pc case fans I've got kicking around for a non-pc project. peepsalot posted:Yeah if you wire them all in parallel, then as long as you supply the correct voltage, and your power supply is capable of outputting at least the sum of the load currents, it will work. A pair (320mA total) is probably fine for a 1A wall wart. If you were talking 5 or 6 I might say something like: No idea about those little fans but not turning them all on at once may be a good idea because of in rush currents. Without datasheets about the fans and the power supply can't say if it'd actually matter.
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Aug 20, 2018 21:00
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If you haven't already, get a cheap multimeter and learn how to use it, you can get a relatively good one on Amazon for like $20 to $30 these days. That way you make sure you hook the fans up in the right polarity, and you can measure how much current is being drawn so you know you're not overworking anything.
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Aug 20, 2018 21:14
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Are most/all soldering irons sold in the US 110V only? I wanted to buy a Hakko FX888 while I'm on vacation since it's twice as much here but it seems like that wouldn't work 
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Aug 28, 2018 20:27
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mobby_6kl posted:Are most/all soldering irons sold in the US 110V only? I wanted to buy a Hakko FX888 while I'm on vacation since it's twice as much here but it seems like that wouldn't work I'm pretty sure a lot of irons just feed the wall current straight through into the heating element so the voltage level is kinda important since it's a simple resistive load.
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Aug 28, 2018 21:22
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You'd be forgiven for thinking so (and some do) but in the case of the 888, it runs at about 24v. They simply use a regular transformer with a fixed primary winding, rather than one that has 2 windings that can be put in series or parrallel.
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Aug 28, 2018 21:40
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Aurium posted:You'd be forgiven for thinking so (and some do) but in the case of the 888, it runs at about 24v. Yeah I guess I was thinking of stuff like Weller, where it uses an actual two-prong wall socket to connect the iron
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Aug 28, 2018 23:08
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mobby_6kl posted:Are most/all soldering irons sold in the US 110V only? I wanted to buy a Hakko FX888 while I'm on vacation since it's twice as much here but it seems like that wouldn't work Yup. It's a constant complaint. I honestly think that's why irons like the ts100 are so popular.
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Aug 30, 2018 12:00
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I think I may be partially colorblind or something. I can't for the life of me tell what color these bands are. Can anyone confirm that these are 22k? 
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Sep 1, 2018 19:30
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I would say so - the leftmost band almost looks brown by itself but not in comparison to the brown tolerance band so I'm parsing it as red red brown red brown. When my eyes are giving me trouble I whip out my multimeter to double-check.
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Sep 1, 2018 19:38
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Oldstench posted:I think I may be partially colorblind or something. I can't for the life of me tell what color these bands are. I bought a ton of those blue resistors so I've been using them and pretty much nothing else (except SMD) for the last like, 6 years, and I've gotten super good at reading them. Yep that's red red black red brown clear as day to me  BattleMaster posted:I'm parsing it as red red brown red brown. You got the easiest one wrong 
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Sep 1, 2018 20:43
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ate all the Oreos posted:You got the easiest one wrong Oops, I meant black but I typed brown. If it was brown it wouldn't be 22k.
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Sep 1, 2018 20:48
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Thanks to you both. Unfortunately my DMM is at a friends house so I had to read bands - which my eyes just can't do. I appreciate it.
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Sep 1, 2018 22:26
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Is there a good reason for coded colour bands instead of numbers?
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Sep 2, 2018 10:36
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Historical reasons I bet. And with bands you don't have to care about mounting your resistor with the number facing up.
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Sep 2, 2018 13:31
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Splode posted:Is there a good reason for coded colour bands instead of numbers? Wikipedia says because it used to be hard to print small numbers.
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Sep 2, 2018 14:13
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That's fair, though the colour choices of orange red and brown are salt in the wound.
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Sep 3, 2018 00:44
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Spazzle posted:Wikipedia says because it used to be hard to print small numbers. Yep. Is a lot easier to spin the resistor against a rack of tiny paint brushes as it goes through the chute than to print teeny numbers that would be just as hard to read anyway.
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Sep 3, 2018 01:16
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Splode posted:That's fair, though the colour choices of orange red and brown are salt in the wound. Something about the colour contrast against those blue metal film resistors makes it harder also. It was always easier to see the bands on the light beige carbon resistors, but they're much less common nowadays.
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Sep 3, 2018 02:01
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Yeah I prefer the tan ones over the blue and aqua ones for readability.
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Sep 3, 2018 02:59
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Any advice on what's the best/low frustration option for a reflow oven under $1K or so? I want to start designing boards using SMT and the thought of extensive hand soldering is giving me pause. Not sure if good options exist but meh
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Sep 3, 2018 05:53
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You can easily do most rework with a decent hot air station, and less easily do it all with a fine tipped iron. People have also hacked toaster ovens to decent results, but given the choice of one, I'd go with the hot air station. Having both is nice though
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Sep 3, 2018 06:05
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shovelbum posted:Any advice on what's the best/low frustration option for a reflow oven under $1K or so? I want to start designing boards using SMT and the thought of extensive hand soldering is giving me pause. Not sure if good options exist but meh I just toss my boards on a laboratory style hot plate. It's definitely not a set-and-forget solution, but I've reflowed a few hundred boards this way without any major issues.
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Sep 3, 2018 06:17
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What do you folks recommend for cleaning no-wash solder flux off of boards? I know it's not going to corrode the board/joints, but it looks like poo poo.
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Sep 3, 2018 07:36
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99% ISO alcohol and an old toothbrush
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Sep 3, 2018 07:59
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shovelbum posted:Any advice on what's the best/low frustration option for a reflow oven under $1K or so? I want to start designing boards using SMT and the thought of extensive hand soldering is giving me pause. Not sure if good options exist but meh I use a cheap hot air station, solder paste in a syringe with small metal needle, and one of these: https://www.amazon.com/gp/product/B00BK772Y4/ Works fantastic. e: Actually it appears I have the "853A++" version which strangely isn't sold anymore, idk what's up with that, but I think it's just the same heating element with a different interface 
Shame Boy fucked around with this message at 08:26 on Sep 3, 2018 |
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Sep 3, 2018 08:24
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ante posted:99% ISO alcohol and an old toothbrush Make sure you actually get 99% alcohol, generally sold specifically for cleaning. The medical-grade stuff contains a significant amount of water and tends to leave a residue
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Sep 3, 2018 08:24
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ante posted:99% ISO alcohol and an old toothbrush The darasheet for the solder specifically states IPA won't clean it.
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Sep 3, 2018 13:21
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Oldstench posted:I think I may be partially colorblind or something. I can't for the life of me tell what color these bands are.
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Sep 3, 2018 17:18
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Oldstench posted:The darasheet for the solder specifically states IPA won't clean it. I’ve used acetone to good effect.
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Sep 3, 2018 18:00
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Oldstench posted:The darasheet for the solder specifically states IPA won't clean it. Datasheet, shmatasheet
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Sep 3, 2018 18:08
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You guys have given me a lot of tools to purchase, which is a good feeling. What's a laboratory style hot plate anyway?
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Sep 3, 2018 18:08
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Its like a kitchen hotplate, but more scientific. And sometimes it has a built in magnetic stirrer.
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Sep 3, 2018 20:19
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Oh yeah like in chemistry class
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Sep 3, 2018 20:35
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mobby_6kl posted:Are most/all soldering irons sold in the US 110V only? I wanted to buy a Hakko FX888 while I'm on vacation since it's twice as much here but it seems like that wouldn't work I believe there is a tap on the transformer inside that you could switch over to use 230, but don't quote me on this. Something to consider if you are looking for a budget conscious but higher performance soldering station are the generic chinese stations that use the newer T12 internal heating element style tips. I picked up a 75w one branded "KSGER" and a few tips for about $100 and the difference in performance compared to my old pace st-45 is pretty mindblowing, they usually have either internal universal voltage supplies fed from an IEC connector or cheaper variants with a DC barrel jack where you just supply your own old laptop power brick or something.
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Sep 5, 2018 00:21
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Ultrasonic cleaners work pretty well for cleaning PCBs too, I run mine with 99% iso for PCBs. The issue with using iso+manual cleaning is it's less consistent, and often not enough solvent is used so the edges of the cleaned area contain a lot of dissolved flux. The result is a sticky board. For no-clean fluxes the recommendation is to not clean them since it can be worse for reliability than poorly cleaning it. No-clean flux is designed to contain the flux inside little sealed bubbles and cleaning it breaks that seal. An ultrasonic cleaner will remove that flux too, but it's mostly mechanical action rather than dissolving it (it takes much longer to clean it as a result). My process is usually 10 minutes per side in iso and a rinse in clean iso right after pulling it out. Obviously ultrasonics aren't suitable for all kinds of PCBs, crystals and MEMS stuff can potentially be damaged (never had an issue myself though).
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Sep 5, 2018 10:05
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I've got a project I'm working on but I wanted to verify if my thinking is correct before I get too far down the rabbit hole. I'm putting together a high altitude balloon I want to launch in a month or two and I'm currently building my payload. I just finished building a trackuino and posted that to the amateur radio thread but this has to do with power. I'm putting everything in a small insulated foam container so I figured I could use a LiPo battery since it would be well insulated. It's a 5200mAH 4 cell lipo and I want to power: - arduino + trackuino shield + sparkfun venus gps + radiometrix hx1 10mw transmitter - 1.3ghz video transmitter + quadcopter camera (like you'd use on an R/C plane) - Canon SD1000 running CHDK directly wired into buck converter bypassing internal camera battery (shooting still photos) - Canon SD1000 running CHDK directly wired into buck converter bypassing internal camera battery (shooting video) I figured I could split a few pairs of red/black wires directly from the battery and use a DC to DC Buck converter *per device* adjusted to the input power required by each device. These are what I'm wanting to use >> https://www.amazon.com/eBoot-LM2596-Converter-3-0-40V-1-5-35V/dp/B01GJ0SC2C So in this example I would use 4 of these buck converters running straight off the battery. I thought this would be cleaner than having 4 separate battery packs to charge and mess with (and potentially fail) Will this be safe or will I end up with a high altitude fireball?
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Sep 6, 2018 20:18
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What are the power requirements of each component?
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Sep 6, 2018 22:49
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