Archived threads in /diy/ - Do It yourself - 249. page
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Hello /diy/nasours
I wish to create a bunch of ups systems so that networking equipment can continue to work during a power outage.
All UPS' will have 2 lantern batteries in series to make 12 volts, however not all equipment will work on 12v, eg switches running on 5v.
I plan on using 5v buck regulators to regulate down the voltages of the batteries however I am unsure how I will do this with my (well, "modified") design, because right now I am tempted to make them all 12v systems with regulators just chucked on the output.
I may have...
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OP here
Must remind you that the batteries are disposable and are non rechargeable.
Are they safe for use in this circuit?
>>910873
>>910874
Why would you waste money on throw away batteries? For less than $20, you can buy small, sealed, maintenence free 12v lead acid batteries...for things like UPS' and alarm systems. You top the charge off once a month with a cheap car charger.
Why would you waste energy bucking voltage from 12v down to 5v? Build a dedicated UPS for 5v stuff. Could use 6v battery of same type I mentioned above. Might not even need to buck it down to 5v, but if you had...
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>>910886
Cost reduction, the lantern batteries are 3 to 4 quid each.
I can eventually upgrade them to lithium ion cells in the future. A single 18650 cell is the same price as a 6v lantern battery.
Here is a video about how to crack open your own geode.
https://youtu.be/UTaE1pGtZVs
too much work, just throw them at oncoming traffic.
>>910824
With a masonry blade.
https://www.youtube.com/watch?v=QtT3x7goeaU
No really,
https://www.youtube.com/watch?v=s0leQk0-4ZY
>>910824
That is one big-ass geode.
I'm buying a dual voltage TIG welder 110v/220v.
I'm going to add a single 220v recepticle in the garage. Which amperage breaker and type of wire should I use? I'm getting different feedback from 30 amp to 100 amp and to use 10 gauge or 8 gauge wire. Do I use romex and do they have them in larger than 12 gauge with 2 blacks or 1 red, 1 black plus ground?
I don't want to run conduit around the garage. I want to feed the wire from the breaker box to the other wall.
10/2 Romex with ground, double 60 amp breaker.
more distance = fatter wire because there'll be a loss of voltage over the run and you want to minimise that.
old transformer welders dgaf about volt droop, but inverter welders that haven't been designed as 'generator safe' die horribly.
calculate your breaker based on the resistance of a dead short at the far end of your wire run. if a short circuit draws less than the trip current of the breaker all your shit burns down.
I'd strongly suggest you read your country's wiring regulations.
It's going to be less than 30 feet of wiring from the breaker panel to the recepticle
I got bookcase like this. I want to hide stuff i got inside. Was thiking about getting some kind of curtain but im also thinking about some cardboard doors. I never seen anything like that though. Any of you have some ideas or examples to inspire me?
>>910675
try a door
or drawer
or hidden room to put it in
really this is not new, the wheel and all the cousins has been invented
just make a god damn door
They will be too heavy (doors) i suppose. Thats why i was thinking about cardboard ones but never seen any examples.
>>910675
google pantry cabinet.
>>910678
No, plywood or a frame and panel door would be like 5-10 lbs. If too heavy, instead of having one door, it would be split up, so you'd have two or three.
A concern for the doors though, is that you may need to screw the bookshelf to the wall, because when pulled open, that tall thin guy may tilt forward.
Ok, /diy/ I'm trying to make myself a tiny portable FM radio, inspired by foxhole radios, with an added generic amplifier circuit. Pic related it's the schematic.
So on the left is an inductor L1=100uH with 2 caps. A C2=22pF and a variable C1=(2-10)pF cap to keep the frequency between ~103-89 MHz. The limiting part being the 10pF variable cap available locally (the only one available).
Since I can't find a germanium diode like the 1N34 I'm settling for a silicone alternative a 1n41448.
C3's are high pass filter capacitors 0.1uF
The rest of the circuit is a generic amplifier.
The core component being a transistor I chose to use a 2N4904. Now biasing it was a bit of a challenge. So I would be glad if someone could check this part for me. R1 = 5k6 R2=1k R3=10k R4=20k.
The battery is a standard 9V battery, since I'd like to fit the whole thing in a small tin box I have laying around.
So my question is will it work?
Will the diode let the signal through? What will it's voltage be? I looked at the data sheet for the 1N4148 it's min voltage seems to be 0.68V with a pretty long antenna (175-200cm) will it be enough? With the 0.68V assumed I biased the transistor but is it correct?
A 100uH on the VHF band? How did you get such a high value? With the formula f=159/(sqrt(L*C)) [MHz, uH, pF] I`m getting between 2.8 to 3.2MHz and that is HF band.
Also the detector in your circuit is for [A]mplitude [M]odulated signals, you will only catch international stations from around the world or some strong local ones. The diode is good but only for the HF bands.
The bias for the transistor is quite high and the tranz will be wide open. 3 to 6V ratio smells like magic smoke.
Please, before you continue to the depths of despair as why it`s not working, atleast...
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>>909943
Ty for the info anon I'll re check my equations...
Isn't the formula f= 1 / ( 2*3.14(sqrt(L*C)) ?
Still that's very high for AM.
You wouldn’t happen to know where I could read up on the theory from a reputable source... I'm scrapping this together form old physics books from university and most stuff I look up online isn't reputable or reliable or is very basic to the point of being useless.
>>909966
1/2pi = 0.159 and your equation uses F, H and Hz.
The radio in your pic is what can be used to receive AM. It's basically a crystal set with an amplifier and both the circuit topology and the component choices suck at 100MHz FM.
You can try your luck with regenerative receivers or one-chip-does-it-all type IC receivers (TDA7000 or whatever is its current iteration). Or you can build a superhet, but it requires much more work and skill.
Usually people building radios start from simple AM receivers, but better...
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/diy/, how can I play electric guitar at a picnic without using a generator?
>>909771
Car battery that bypasses the amps power supply and feeds 12V straight to the amp board.
>>909772
How long would an average car battery last, at pretty loud volume on, say, a 20 watt amp?
>>909772
Most guitar amps run split rails. A very well filtered switching converter perhaps.
how do i diy a treestand for a 8' xmas tree.
>>909084
those stands are fucking horrible. I hate them with a passion
>>909084
I know some one that sells these. It is just a pipe with a metal plate welded to the bottom and holes for nails/screws/bolts. They look better than this one and are painted green. They are heavy and rugged.
>>909086
Those stands are supposed to have boards of proper length screwed to the bottom... (hence the holes in the feet) and are kept as small as possible for storage reasons... Now explain to me how they are so bad..?
Im doing a live edge black walnut coffee table. I've got a 74"x20"x2" slab that still needs to dry (pic related). Is there a way to tell how long I should let it dry for? A month? A year? I literally have no bearing on this sort of thing.
Why'd you buy a green slab? Shit can take years to dry properly. Rush it and it'll crack and you'll be screwed.
>>908517
It was cheap as all get out.
>>908526
Aren't they cheap because they haven't gone through the potential failure of drying, storage, or milling?
What are some good alternatives to pocket holes?
![good_wood_joints0011[1].jpg](https://i.imgur.com/puK7RFf.jpg "good_wood_joints0011[1].jpg")
>>908135
Literally any real woodworking joint.
>>908137
What if I want to have some planks parallel to each other?
>>908144
>>908144
Glue
Clamps
Dowels
Or biscuits
Router the edge to make them smooth
Alternate growth rings to reduce cupping.
so, my company will be getting one of these for me in my little office. the 75 watt CO2 version can cut through up to a half inch of wood at a time(that was the estimate given to me by the sales rep). it can cut and engrave, basically everything that isn't metal.
what kind of neat ideas can you think of that I might be able to try off the clock, after hours, and with my own material? I'm thinking of things I'd use with my /tg/ friends like props and stuff, also stuff I'd make for the local fetish community, but I'm very unoriginal
that...
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pmma (acrylic) is really nice to work with and its pretty cheap. i have made a few things out of hours with this for robots and stuff and its great fun. spent entirely too long drawing a penis to raster onto a set of coasters
always manual focus. never use epilog auto focus. one time i tried it out and basically 'sensor' switch that tells the table to stop just slipped to the side because of its ridiculous design. the table crashed into the head and the machine panicked. needed to reboot to manually focus to get the table down but on reboot the head would auto calibrate and when it realised it was stuck it would panic again.
machine was out of service for two hours because nobody had a screwdriver to take the front panel off and manually turn the belt in order to drop the table. fucking pain in the asshole.
why is it possible for the table to crash into the head in the first place anyway?
but yeah great fun.
>>901119
>always manual focus.
noted, for future reference...
>had a screwdriver to take the front panel off and manually turn the belt in order to drop the table.
my supervisor is a tool-whore, glad to say that even if it's got a weird-ass screw head on them panel screws he probably has the driver to screw them properly.
>why is it possible for the table to crash into the head in the first place anyway?
because in applications like this the engineer is too busy thinking "IT NEEDS TO MOVE A LOT AND MORE MOVEMENT RANGES MEANS WE CAN CHARGE MORE MONEEEEYY; SO I WANT IT TO HAVE ALL OF THE MOVEMENT" without thinking about how adding more "range of motion" will result in equipment crashes.
>spent entirely too long drawing a penis to raster onto a set of coasters
no shame man, none at all.
I am certainly gonna try and build a folding, layered yolk(fetish type). if I can get that in acrylics I could probably sell them for loads-a-dosh to the local community.
that and I want to see if I can legibly engrave poems onto things, like a little plastic prayer card with the full text of "If-" or "The Hymn of Breaking Strain" on one side cut deeply into the plastic.
>>901140
>weird-ass screw head
sad to say it was a pozidrive.
there were 3 toolboxes in that room and none of them had anything close. wtf.
i guess it depends on the machine but rastering for engraving can take fucking ages. like a boring amount of time. and then whoever is in charge insists that you have to watch it do its thing for fire safety it gets fucking boring super quick. bring a book. or something to do.
i think it was a 40w, 10mm acrylic took two passes but the thicker...
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Alright guys, hopefully I don't catch a ton of shit for this.
Basically I am doing a Gofundme to afford the machinery and equipment necessary to make prosthetic limbs. The plan is to use the CNC mill and 3D printer to make other things I can sell to fund the creation of the custom prosthetics, so that I can give them away for free, or at least at a very low cost.
The problem being that I have had no luck getting any donations, despite trying to build up a social media following.
So I guess my question is where are some good places, or people I can talk...
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>>912321
Donald Trump.
Fuck off.
>>912322
Well alrighty then.
>>912321
Have you made prosthetics before? If so post pics.
Help me build a drone that can be controlled by smartphone. I don't see too many of those built. Completely new to building drones, any good guides?
>>910599
Wow.
1. 'UAV', not 'drone'. UAV.
2. Google this before posting.
>>910608
>UAV
multiroter
>>910622
>multiroter
quadcopter
