/diy/ - Do It Yourself

>>1787229
!7WqQ1T/q2E isn't a secure tripcode, retard.

This is.

>>1486242
>add batteries to an existing pack that is charge/discharge managed
You should not do this, especially with Li+ cells, and most certainly not with Li+ cells that are not the same production run/age/level of wear.

Li+ cells need charge/discharge controllers of some sort because they're delicate. If you discharge them too much or too fast, they overheat, short out, and catch on fire. If you charge them too fast or overcharge them, they overheat, short out, and catch on fire. If you're rebuilding a Li+ battery pack you change ALL the cells at once with cells that are new, preferably from the same production run, so they're closely matched, otherwise the odd-man-out cell will likely overheat, short out, and catch on fire.
You don't add cells to an existing pack because the charge controller isn't configured for them, and because the cells in parallel aren't matched, and one or the other will inevitably and eventually overheat, short out, and catch on fire. When that happens there is a cascade reaction, the fire from one the one cell overheating the other cells in succession, causing them to short out and also catch on fire.

If I sound very repetitive it's because I'm trying to impress upon you how finicky Li+ cells are with regards to how you manage them and use them and that you should NOT under any circumstances do what it is you're implying, it is a BAD idea.

Source: I worked for an engineering firm that was thinking of building Li+ packs to run training systems for the military, and I did the research into using them, and what sort of system you needed to manage them properly.

A charge controller can be as simple as watching cell temperature, and watching charge/discharge current, and managing charging voltage, cutting off charging and discharging at predetermined points, or it can be as complex as a 'coulomb counting' system, that literally keeps track of cell charge state as it charges/discharges, as well as cell temp and charge/discharge current.

>>1486585
I've never used a Keithley in quite that way but I'm pretty sure you can put it in a MIN/MAX mode that will do what you want it to do. RTFM, OP.

>>1479321
FFS dude call family or friends and couch-surf or at least, you can't possibly be completely alone in the world you must know someone, or at least go find a goddamned homeless shelter that has room.

>>1484025
Depends entirely on whether or not there's a transformer electrically isolating the input from the output. If your pic is the SPS you're referring to then the ground is very likely common to the input and output, Use an ohmmeter to verify this.

>>1476758
FWIW on this subject:
Had a washer and dryer that were probably 30 years old at least, bought them used 10 years ago. Last month the dryer died, replaced it with another used one, this month the washer died, won't spin anymore. Not worth the time to repair something that old and used up. Went looking for another used one, got real lucky, found an older couple selling a 3 year old Maytag HE toploading washer for all of $100 (thing cost $1000 new!) because 'they didn't like the way it worked, and got a traditional washer with a large agitator' instead. Not a damned thing wrong with this one, 'gently used', in like-new condition, works perfectly. Small agitator in the bottom. Used it several times so far, so long as you select the right cycle type, it gets things perfectly clean. May take a little longer but it gets the job done, even got the California King-sized heated mattress pad I have (gigantic, bulky) clean. Biggest difference in using one of these versus a more traditional non-HE washer is you have to be careful how much detergent you put in it, it only takes a fraction of what you're used to using, and if you put too much it may actually sabotage the wash action. No complaints about this, I think it's great, glad I got such an amazing deal on something used.

A basic understanding of Ohm's Law should be a requirement before being allowed to post threads on /diy/.

>>1473331
OP, your 'customer' likely doesn't know what the fuck he's talking about and is wasting your time. Inductors like those rarely if ever go 'bad'. I'd want to see on a schematic where they are in the circuit, too, if they're just there to filter incoming power supply noise then I'd say he's full of shit and there's nothing wrong with them.

>>1460524
OP, you should probably consider installing an actual outlet where the washing machine is, on it's own circuit, rather than piggyback on the one for the water heater, which I'm pretty sure needs to be on it's own separate circuit.

>>1452877
If it's POTS (Plain Old Telephone Service, aka analog phone/landline) then the voltage drop when you take the receiver off-hook is how the central office system knows you're off-hook; if you draw too much current from the line, it'll assume you're off-hook all the time; eventually an operator will be alerted, try to break into the line, see if you need emergency assistance or something. Eventually they'd send someone out to see if there's a short somewhere in *their* lines or junction box, and eventually knock on your door to see if there's a problem (if the operator didn't alert the police to see if there's a problem that needs their attention). Eventually they'd probably just physically disconnect the line if they got no response from any of the above. In the end you wouldn't be able to draw much total power from the line without causing problems like the above. A solar panel would be a better option if you need 'free' power.

>>1451950
Last time I checked there's beginner kits that would be appropriate, and when it's done he has something he built that actually does something. if he likes it then there's more complex kits of course.

>>1433081
You're in luck. I repaired coin-op games for 15 years, and at one point I was having people from all over the country send me pac-man boards.

First of all since you converted it to an external 5V supply, be sure to measure that at the farthest edge of the PCB and adjust it to 5.05-5.10 volts. I see you're using a PC supply, those aren't adjustable, get a supply you can adjust, the PCB is sensitive to supply voltage. Also beef up those supply wires, use several 18 gauge.

You don't even need those big filter caps if you're using an external supply, they're only when using the original Midway 14VAC center-tapped transformer with the onboard linear supply.

Second, the daughtercard converts Pac to Ms. Pac. You can pull the Z80A off the daughtercard can plug it straight into the 40 pin socket and it'll come up as Pac but with some wrong characters on the screen.
The Z80A can go bad, you can replace it with a Z80A, Z80B, or Z80C. They're a few bucks these days but you'll likely have to order it from somewhere.

The screen RAM is all 2114's, 1kBx4 static ram (6 18 pin socketed). They can go bad and the POST routine in the program will error out if one or more is.

The 4 heatsinked 16 pin chips are the motion object RAM. Usually don't go bad and POST doesn't test them.

The smaller daughtercard (28 pin socket next to the Z80A socket) is a bus transceiver. It can go bad but it's rebuildable.

See 2 of the 4 program ROMs have no windows? Mask ROMs. The pins corrode and can break off. Also the sockets can go bad. Really the sockets on everything can go bad, check and/or replace them.

There are 4 16 pin bipolar ROMs, two are for video color palettes, two are for sound generation. If any of them go bad you're in trouble, hard to find and harder to make replacements for.

Best tools for debugging this are a multimeter and a logic probe. MPU clock speed is only 4MHz and everything else is derived from that.

>>1443878
The only thing worse than an ignorant cunt is an ARROGANT ignorant cunt. I've only been working in electronics for about 35 years, but sure kid you've been dinking around in it for a few months and know everything already.

>>1443863
You don't seem to understand transformers or oscilloscopes or basic electronics.

The secondary winding is BY DEFINITION isolated from the mains because it's a TRANSFORMER.

Now, if your 'scope has a hi-Z input impedance (like 10M ohm) then the CURRENT will be small and then it's only a matter of the 'scope being able to handle the voltage (which you didn't mention). If it's got a 50-ohm input impedance then you should NOT be connecting more than, say, 5 volts pk-pk to it, you'll damage the input channel.

Now, why do you want to connect a power transformer to your 'scope? What are you trying to accomplish?

>>1046199
We don't actually know about the welder. The answer is probably no, but I would love to make a robot that DQ's the other one by physically making it >250lbs by the end of the match

Entanglement like lines and nets are a big no-no. They kinda make things boring anyhow, they'll disable all the exciting parts of another robot without a bang or a boom.

>>1044535
I swear Nave is theredpill incarnate, the shit he says and does is pretty crigeworthy. Zoe is certainly your standard SJW/3rd waver or whatever, but she's very respectful to people that she knows personally. He had a beef with her, she just doesn't have beefs with people she knows.

>>1044539
When those two showed up it would turn into old guy 'let's talk about how great things used to be back in the day' time, and since Ray's got his reputation, people tend to shut up and the conversation becomes almost exclusively about them.

Have you ever seen boomers who are really into a hobby, any hobby, talk with each other? That's what it was, and it made me pretty self-concious of how much money I had just spent and how much of my life I just burned on a hobby.

At least with most of the other guys we would shoot the shit on each other's life stories, fuckery we did to get here, and where we were going in the future; our after-hours conversations were maybe only a quarter to half about Battlebots. When Ray or any of the other old-timers showed up, it was exclusive about "back in the day when things were more hardcore"

>>1044178
Personally, I drank a lot, especially with Basilisk, Scorpios, Wrex, Dick Stuplich, and a few others. Everything got kinda cringy when Ray, Brian, or Brad showed up though.

>>1044178
Varied. Some people fucked off to enjoy their paid-for vacation in LA, others kept tinkering with their robots in preparation for possible rumbles, most watched the rest of the fights from the audience.

tbqh, there wasn't that much inter-team helping hands in the later stages of the tourney WITH THE PRIME EXCEPTION of Yeti who a lot of people found a way to help with.

>>1044166
>>1044153
>>1044151

It's absolutely wrong. He made some....interesting choices for the next round, but common sense should help you figure out how it works.

>>1044058
Flipping yourself over doesn't actually detract from your score. Weird, right?

Judging is FUCKED this season, especially since they went with the new rules right AFTER the SawBlaze/Razorback fight. Usually in sports, it's not the custom to change the rules after the competition has begun.

>>1043635
>Ovehaul
>MIT

I want this meme to die

>>1043636
Robot Wars had a £1,000 stipend, which thanks to Brexit, was pretty much nothing

>>1043837
>>1043691
Battlebots had SEVERE restrictions on approved sponsorship. They were bendable, sure, but even then it's incredibly hard to get a sponsor. The teams that did it well had a single team member full-time sucking corporate D to get money.

>>1041684
Two of the robots there were at 240V DC officially. The Dentist was using a sub-ohm EMRAX airplane motor for a weapon motor, driving it with a Prius motor controller and Road Rash was doing...something... to get some high voltages to run their linear induction motors. No surprise those two didn't compete, it is hard as hell to work with >100v DC systems, shit blows up for no reason.

>>1042912
Arena for Battlebots is already 1.5" thick flame-resistant polycarb which is definitely good enough for a .22 and more. The battlebot I built, and the vast majority of them are clad in properly-reinforced AR400 and AR500 steel, which most people use for .45 targets. The box costs about a million dollars; having to make a new one that can contain AR500-piercing rounds is gonna be in the tens of millions.

Some of our friends did pitch a completely autonomous robot, and here was the studio's response: "This is a character-driven reality TV show, we're here to get the human reactions during a fight. Autonomy removes that completely"

Really my biggest problem with this 'increase in scale' is "who the fuck is going to pay for it?". ABC was unhappy to shell out 6 million, of which .5 Million went to actually building the robots. Megabots got that much from Kickstarter alone, plus a few million from various corporate sponsors and VC sources just for a glorified bulldozer with a paintball cannon.

Travel IS an issue. Battlebots will pay for your travel fees, Robot Wars won't (which is why nearly everyone in RW is from the UK).

Battlebots rules here:
http://battlebots.com/rules/
Robot Wars rules here:
http://www.robotwars.tv/faqs/

Rules don't mean much for either, as they were both changed on-site mid filming. Besides, both competitions are invite/application only, they don't let just anyone in.

The amateur league, however, lets any random fucker with his Autism RC Car in.
http://www.buildersdb.com/

>>1040780
>>1040089

Rumbles:

Animals
Little Girls
Former Teammates
Vertical Discs
2 is better than 1
Californian Animals

I hope I don't get in trouble for this....