asdf32 posted:

Consider adding the TL431 to your repertoire though.

asdf32 posted:

You could also look for cheap/broken/used tools of ebay. Though 40V won't be too common so it might be hard.

Methylethylaldehyde posted:

Yeah, no luck there. Which is a shame because I have the cordless weedwhacker and it's disgustingly awesome, and figured it would save me having to buy or source a 36-40v battery pack for the project.

Stabby McDamage posted:

Use two-sided protoboard, or even better, stripboard (which has conductors running the same way), then use a bandsaw, dremel, or nibbler to cut it to size. Install female header topside in the middle two rows and male header bottomside on the outer two rows. Then the ESP can span the ridge in the middle of the breadboard.

Or, ditch the 8-pin ESP8266 and just get a NodeMCU or similar host board with onboard USB, and everything will be 10 times easier.

Sagebrush posted:

ate all the Oreos posted:

Just so you know I have the same ESP8266 (-01 I think it's called?) with the dual-header and while I can get it to run and talk to it over serial I have never been able to successfully get it to run a program and I have no idea why not, even the example programs delivered in the exact standard way don't run on it. Maybe it's a counterfeit one or something idk

JawnV6 posted:

Nice precision antenna mod

Stabby McDamage posted:

I spun a host board with buttons just for this purpose way back when that board was fairly new.

JawnV6 posted:

Nice precision antenna mod

Stabby McDamage posted:

What does the antenna mod do? Doesn't that screw up the RF moon magic that makes it work?

Sagebrush posted:

In this case, it *is* the RF moon magic that makes it work. I was getting really lovely reliability on this bag of AliExpress NRF24L01 modules and YOSPOS ham radio guy Jonny 290 suggested that whoever cloned it might have hosed up the circuit design and it didn't have enough antenna load on it, or something like that (I don't understand RF either). After soldering the wire on it worked perfectly -- better than 120 feet line-of-sight. Magic.

Sagebrush posted:

In this case, it *is* the RF moon magic that makes it work. I was getting really lovely reliability on this bag of AliExpress NRF24L01 modules and YOSPOS ham radio guy Jonny 290 suggested that whoever cloned it might have hosed up the circuit design and it didn't have enough antenna load on it, or something like that (I don't understand RF either). After soldering the wire on it worked perfectly -- better than 120 feet line-of-sight. Magic.

Kasan posted:

I didn't see an Electrical megathread so I'll ask here.

<scary house wiring issue>

Rexxed posted:

I have no idea but you should definitely ask in this thread:
Don't burn your house down: the wiring thread.

Kasan posted:

I didn't see an Electrical megathread so I'll ask here.


I have an electrical issue that I have the knowledge enough to repair, but I can't seem to diagnose the issue. A couple days ago I had an outlet die on me with a lovely pop of blue smoke. (pluged into it was a 1/8 HP motor running at the time, and this outlet has solely been used to power that outlet for about 4 winters now as it's attached to my fireplace insert). I thought no biggie, I'll replace it.

Well, it turns out that when it blew, it took literally 50% of the electrical outlets, lights and ceiling fans with it. Again no biggie, I'll go replace the fuse and reset any circuit breakers that popped.

Now here is the problem. The entire branch that's affected ISN'T attached to a fuse or breaker as far as I can tell. I could go to each outlet in the house and test for voltage, but I have no way of telling if the outlet I'm checking is on that branch or not. I know there's a tool that you can plug into a circuit and it'll tell you roughly where the break is in terms of wire distance, but the name escapes me and I'm not even sure if it would help. There isn't a wiring diagram for the house, and the labels on the ancient fuse box and break box aren't even correct.

Hell the hell do I fix this problem? It's mostly an inconvenience because I no longer have a porch light, living room light or guest bedroom light, but as much of an introvert as I am, I'm not a troglodyte and having only computer monitors for light sources is an eyestrain.

Things I've done:
Checked every fuse and found none dead
Checked every breaker, and all of them are on
Replaced the receptacle that I thought was the issue with a new one (and was horrified to find the ground wire was grounded to the junction, not the receptacle)
Metered a couple circuits I knew were on the same branch due to placement (guessing) and found no voltage.

Things I'm unsure of but willing to test:
Metering every outlet in the house with live current and tagging all the ones that come up dead. Unsure if I find a dead outlet next to a live outlet, does that mean that outlet is the issue or is it a different branch. Would ANY outlet on the branch comeback as having current with the current situation.)
Crawling under the house and looking to see where most of the romex goes and trying to trace the line. A ton of the house has the power lines just under the subfloor going from point A to point B. Since I've been educated in the ways of residential electrical networks I've yet to crawl down there and figure out where everything is going.)

My fear: There might be a junction behind the wall that burned out that I have no way of finding with out tearing out every wall in the house.

Can anybody advise me on what to do? I'm capable enough to do it, and have about 80% of the tools a professional electrician has due to my schooling. I literally can't afford a professional to come out and fix it so I'm pretty much on my own here

ate all the Oreos posted:

I tried using a transparency / UV etch resist thing to make a homemade board the other day and it wound up coming out with a bunch of half-exposed area where the toner let through a little bit of the UV. I knew toner had microscopic holes but I had no idea it was this bad. Anyone have a tip to fix this, or do I need an inkjet, or what?

Splode posted:

It does not need a bleeder resistor. There's gently caress all energy stored in a cap at 5V. An electrolytic cap for decoupling an IC is an unusual choice, a ceramic cap (usually 100nF) is usually all you need. Is this for a really powerful processor IC or something?

ate all the Oreos posted:

I tried using a transparency / UV etch resist thing to make a homemade board the other day and it wound up coming out with a bunch of half-exposed area where the toner let through a little bit of the UV. I knew toner had microscopic holes but I had no idea it was this bad. Anyone have a tip to fix this, or do I need an inkjet, or what?

poeticoddity posted:

A ceramic cap was insufficient in the prototype. The ICs are 16 channel PWM controllers sinking 20 mA per LED, so each IC's sinking about a third of an amp at times, and I was getting some nasty low-frequency flicker at certain duty cycles. From what I've been able to find, it looks like the solution to that is putting an electrolytic in parallel to the ceramic cap, and the ceramic cap will handle the high frequency noise that would disrupt the IC functioning while the electrolytic will help with what I assume are current availability issues. The visible flicker was decreased with shorter cable lengths (which would have less line loss) so I'm hoping the caps will fix the problem and I can go back to slightly longer cables.

poeticoddity posted:

Potentially stupid question: Does an electrolytic capacitor used to decouple an IC need a bleeder resistor if everything is running at 5V?

Most of what I've seen is for systems running at high voltage or where there's no parallel IC, which my gut tells me is sufficient to discharge the capacitor when power is disconnected.

Splode posted:

Righto, fair enough. You still shouldn't need a bleeder resistor though, even if you need a decent array of decoupling caps. Bleeder resistors are only really necessary for higher voltages that can hurt people.

KnifeWrench posted:

I have a co-worker who swears by bleeders on everything, as a way to make sure upstream power control circuitry can reliably hard-boot the microcontrollers (I.e. if a short pulse turns off power, the capacitance won't keep the MCU alive). If that's not something you need, you're fine, and he's probably paranoid anyway.

BattleMaster posted:

Are you running it at the rated voltage? If you are then you're probably seeing ionization from the avalanche discharges that happen following an interaction inside the tube and it's probably okay. I've never seen or heard about visible discharges because the radiation given off by the ionization is into the UV end of the spectrum but depending on the gas mix I guess it could be visible.

If you don't know what the rated voltage is and you have a variable supply and a way to measure the count rate you can figure it out pretty easily. Put a source near the tube and starting at 0 volts increase the voltage until you start seeing counts. Taking note of the count rate start increasing the voltage in steps of 25 or 50 volts at a time and you should see a count rate versus voltage relationship like this:


(ignore the numbers on the axes because they will be different for any given tube)

Once you figure out where the plateau is you want to operate the tube at about 1/3 to 1/2 of the way between its start and end voltages.

ate all the Oreos posted:

e: So to be clear, it's safe to run it up to the point where it outputs continuously for a brief period of time just to establish where its limits are? I was really worried I'd get some spalling or something that would ruin it.

huhu posted:

Does anyone have experience seeking out a cheap-ish PCB manufacturer that's RoHS compliant? I currently have 10cm*10cm boards that I'm getting made for ~$2 each but they can't guarantee it's RoHS compliant so now I'm looking elsewhere.

CarForumPoster posted:

WHy do you want it to be RoHS compliant?