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Luigi Thirty posted:i got really bored and started writing a basic VERB NOUN text adventure parser in python same but in ruby
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Feb 25, 2014 23:49
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Base Emitter posted:because then if and when the supply is backwards its effectively shorted and the diode is carrying the full current the supply will generate i guess i'm too accustomed to benchtop supplies where i can set the current limit on the supply to like expected operating current + 10%
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Feb 26, 2014 05:46
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OK, can I eliminate the 10K resistor in this circuit with no ill effects? I've always read that I should wire up potentiometers like shown, essentially like a voltage divider, but I have no idea why it needs to be like a voltage divider instead of just wiring the pot's wiper straight to the ADC. I want to get a PCB made, and if the resistor could be eliminated that'd let me make the PCB smaller. I breadboarded it up on an Arduino both with and without the resistor, and the value read back was different. Turning the pot as close to halfway as I could without the resistor gave me 508 (p much halfway for a 10-bit ADC), but with the resistor gave me 406 (not having touched the pot or anything else). edit: the pot is wired up so that one outside pin goes to VCC, the other outside pin to GND. Doc Block fucked around with this message at 08:57 on Feb 26, 2014 |
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Feb 26, 2014 08:52
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a++ diagram doc block
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Feb 26, 2014 08:56
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Feb 26, 2014 09:07
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Doc Block posted:OK, can I eliminate the 10K resistor in this circuit with no ill effects? I've always read that I should wire up potentiometers like shown, essentially like a voltage divider, but I have no idea why it needs to be like a voltage divider instead of just wiring the pot's wiper straight to the ADC. i think you're confusing potentiometers with variable resistors a variable resistor needs to be connected the way that is shown there because it forms a voltage divider and varying the resistor varies the voltage going into the adc. a potentiometer with three terminals forms a voltage divider on its own because you are wiping a contact across a single carbon trace that's connected on both ends. it's even better than a normal voltage divider with a single variable though because both of the resistances are the inverse of each other. imagine like this code:code:so anyway when you are adding the extra resistor to one end of the circuit, you're basically just biasing it in one direction by adding an invariant resistance to that side of the divider. which is why you get 400 instead of 500 with the pot centered. code:Sagebrush fucked around with this message at 09:36 on Feb 26, 2014 |
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Feb 26, 2014 09:26
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irl enjoyed
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Feb 26, 2014 09:30
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Sagebrush posted:you don't need the extra resistor. cool, tyvm.
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Feb 26, 2014 09:38
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actually wait the topology is different. what you are getting is thiscode:
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Feb 26, 2014 09:42
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oooh right your ground is tied to both sides of the voltage dividers you're using and that's going to alter the effective resistance. 'm not going to dig out kirchoff's laws cause it's way too late and i'm going to sleep but basically yeah the topology is all hosed up and nonlinear if you add that other resistor. just leave it out, vcc to one side of the pot and gnd to the other, probe the center pin, you're good to go.
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Feb 26, 2014 09:43
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Thx man.
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Feb 26, 2014 10:25
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you guys wanna see some really fuckin janky electronic hack?  no idea how it survived the bumpy 50km ride home & still worked for months .. replaced it but now somethin else is hosed because of (less janky) hacks just expiring i guess
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Feb 27, 2014 20:55
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 those leads arent even insulated are they
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Feb 27, 2014 20:57
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802.11weed posted:you guys wanna see some really fuckin janky electronic hack? 
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Feb 27, 2014 21:02
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802.11weed posted:you guys wanna see some really fuckin janky electronic hack? excellent
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Feb 27, 2014 21:23
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some of the leads most likely touched others which explains the game acting really loving weird sometimes. there's this sound after you've lost your last ball & the game is trying to get you to buy in for another, it's a lady moaning "ooh, one more time". for a little while it would play that sound clip for every sound effect. every bumper hit, every switch, every fuckin thing it was great
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Feb 27, 2014 21:33
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Base Emitter posted:because then if and when the supply is backwards its effectively shorted and the diode is carrying the full current the supply will generate In several of my radios this is exactly what they do BUT BUT BUT it's intended to blow a fuse upstream of the diode. I found out about these little protection diodes when I hooked a gel-cell battery up backwards without a fuse inline and made a ham radio literally catch fire and billow smoke (it was the diode dissipating 100 amps or whatever stupid amount that battery could source) (and yes I fixed the radio and it works to this day)
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Feb 27, 2014 23:03
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Welp, I sent off to have a PCB made for my fume extractor. It's gonna be a lot smaller than the protoboard version, so hopefully it'll be small enough to fit into an enclosure that isn't xbox huge. Hope I didn't gently caress anything up!
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Feb 28, 2014 02:39
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If I can figure out how to strap my dremel perfectly vertical in my drill press I can drill PCB holes and since I can etch I could then make finished boards at home, would be dope
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Feb 28, 2014 03:36
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Jonny 290 posted:If I can figure out how to strap my dremel perfectly vertical in my drill press I can drill PCB holes and since I can etch I could then make finished boards at home, would be dope i like the way you think jonny
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Feb 28, 2014 03:59
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Jonny 290 posted:If I can figure out how to strap my dremel perfectly vertical in my drill press I can drill PCB holes and since I can etch I could then make finished boards at home, would be dope could you just put a tiny drill bit or grinding head in the drill press chuck and skip the dremel entirely? colbylol posted:i like the way you think jonny
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Feb 28, 2014 04:06
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my dremel wobbles way too much for me to ever trust it with precision work.
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Feb 28, 2014 04:19
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Jonny 290 posted:If I can figure out how to strap my dremel perfectly vertical in my drill press I can drill PCB holes and since I can etch I could then make finished boards at home, would be dope pcb holes like vias? problem with them is they suck if you don't have a plater :-/ soldering lil bitty wires through the holes is a pain in the rear end. just get boards made imo, its dirt cheap anyways
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Feb 28, 2014 04:23
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spoken by a man that doesnt enjoy hand-painting board etch masks with an ugly shade of his SO's nail polish that he's trying to get rid of
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Feb 28, 2014 04:31
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Jonny 290 posted:If I can figure out how to strap my dremel perfectly vertical in my drill press I can drill PCB holes and since I can etch I could then make finished boards at home, would be dope 3d print a mounting plate adapter cradle kind of thing
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Feb 28, 2014 06:25
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i've got a drat computer engineering degree and i still don't know how to make my own pcb, at all. i'm pretty sure i'm not even using perfboard properly
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Feb 28, 2014 17:28
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Werthog 95 posted:i've got a drat computer engineering degree and i still don't know how to make my own pcb, at all. i'm pretty sure i'm not even using perfboard properly install diptrace
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Feb 28, 2014 17:32
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Sagebrush posted:3d print a mounting plate adapter cradle kind of thing I've got enough U-bolts and sheets of aluminum to make shims that I could probably honestly knock this out with a little bit of work
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Feb 28, 2014 17:45
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Glorgnole posted:could you just put a tiny drill bit or grinding head in the drill press chuck and skip the dremel entirely?
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Feb 28, 2014 18:23
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Werthog 95 posted:i've got a drat computer engineering degree and i still don't know how to make my own pcb, at all. i'm pretty sure i'm not even using perfboard properly I remember him refusing to comment on how they sound, said he had a tin ear and just liked building the things
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Feb 28, 2014 18:32
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n o i c e is that wrap wire?
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Feb 28, 2014 18:40
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oh yeah that reminds me i have a spool of 30AWG kynar from way back when i was modding ps2's 
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Feb 28, 2014 18:42
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Jonny 290 posted:n o i c e
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Feb 28, 2014 18:46
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Werthog 95 posted:i've got a drat computer engineering degree and i still don't know how to make my own pcb, at all. i'm pretty sure i'm not even using perfboard properly quick and dirty pcb for giant babbys based on my half-baked memories of my packaging class 2 years ago: -take some copper cladded board and ferric chloride from radio shack -draw traces with a sharpie. there are less lovely ways to do this like printing the pattern from eagle on magazine paper and ironing on but gently caress it, point is ink-on-copper -dip that poo poo in the ferric chloride for whatever listed amount of time it is, i dont fuckin remember. when ur done put some baking soda in that poo poo so it doesnt gently caress up everything wherever you dispose of it -drill, baby, drill any of you knowledgable fuckos feel free to add/correct
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Feb 28, 2014 19:14
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nope thats pretty much it. except one thing to note is that agitation speeds the etch process a shitload. If you want your boards to etch clean and fast, do it in a covered dish that you sit on top of the washing machine as you do a load of clothes just make sure you dont dump ferric chloride on your laundry 
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Feb 28, 2014 19:16
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better yet just go here http://dorkbotpdx.org/wiki/pcb_order and pay like five dollars and get your dumb and bad circuit fabbed on surprisingly high quality 2- or 4-layer boards
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Feb 28, 2014 19:56
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kewl. now i just have to make some circuits.
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Feb 28, 2014 19:57
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Bloody posted:better yet just go here http://dorkbotpdx.org/wiki/pcb_order and pay like five dollars and get your dumb and bad circuit fabbed on surprisingly high quality 2- or 4-layer boards Ordered my fume extractor PCB from these guys (via oshpark.com) and it seems like pretty quick turnaround for the price. Waaaay faster than BatchPCB, who were cheaper but only put your boards in a batch when they could find room on a panel amonst SparkFun's own PCB needs, and since the boards were made in China they had a long lead time and had to come back through customs, etc. edit: but now that I've submitted my order I can't help but think of all the things I could've done differently. Doc Block fucked around with this message at 22:25 on Feb 28, 2014 |
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Feb 28, 2014 22:21
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Bloody posted:better yet just go here http://dorkbotpdx.org/wiki/pcb_order and pay like five dollars and get your dumb and bad circuit fabbed on surprisingly high quality 2- or 4-layer boards well yeah thats the correct answer but the diy method is fun to do once or twice
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Feb 28, 2014 22:38
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So after the whole thing where the diode on my fume extractor was too hot to touch, I bought the biggest diode I could find on Jameco. A handful of them arrived in the mail today. From looking at the data sheet I knew it'd be big, but holy poo poo it's huge. Those leads are about 1mm in diameter. According to the data sheet this bigass bastard will do 6 amps continuous current at room temperature. (those are vanilla 1N4007s on the left) Doc Block fucked around with this message at 03:52 on Mar 2, 2014 |
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Mar 2, 2014 03:49
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