i have question and hope you guys can help me. reently i took apart a couple of wall mounted intercom devices. in these devices i found a speaker and an amplifier. so i thought maybe i can use these parts to make a small portable speaker.
The speakers i found both work. but i have no idea how to wire the amp in there and the best way to supply the power.
the amp model is a TDA1519B. i found the datasheet for it here: http://www.nxp.com/documents/data_sheet/TDA1519_CNV.pdf
my knoweledge of this stuff isn't that high so i can't really figure it out on my own. i was looking at page 8 because it contains a diagram of how to wire it and for so far i think i figured out some of the connections.
PIN 4 and 6 will connect to the + side of the 2 speakers - but where does the - go? is that wired to the - of the battery or to the ground (and how would i achieve this)
PIN 1 and 9 are non inverting inputs. so i assume if i want stereo sound i put the left and right input on these 2 pins. (do i connect the - of the speakers to the - side of a 3.5 mm stereo cable?)
PIN 7 is the supply voltage so this is the place where the power goes in. the document says this should be around 14.4 V with 40 mA. but except for pin 4 and 5 there is no output so again what do i do what the - side.
so this is kinda what i figured out from it but this isn't my field. i know how to solder stuff but i don't really know all this stuff so maybe someone can make a simple drawing of the full schematic? if someone would that would make me very happy.
>>936879 When you ask that kind of questions, I'm pretty skeptical that advice given here will be enough.
Anyway, the symbols on the other ends of the speakers mark ground. There are other grounded things as well and you connect them all together and to your power supply's negative wire. You also connect the ground of your input jack to the same point, as well as the IC's pins 2 and 5. Use short wires and connect the input jack's ground to IC's pin 2 with a separate wire. 40mA is the current... Comment too long. Click here to view the full text.
This thread is for the discussion of design methodologies and how you approach your design process.
For example I have had a dilemma recently where I am in the process of designing a multi purpose device but cannot decide what the primary purpose/use of the device will be(for multiple reasons).
So in short - let's talk about challenges we have faced during our design and mock up phases and how we overcame these since we all know that adequate planning goes hand in hand with a well thought out final product.
>>936787 the purpose of multi purpose devices is to display it in the bottom of the cupboard somewhere.
design something that does one job well. then add features. the multitool for example. it's a pocket knife. who doesnt need a pocket knife? but then you get a trade off over time between how useful carrying around a fucking toothpick and rope cutter and bottle opener really is. but then there is the market for a real all in one tool.
so tell us OP, who do you think will buy your multitool and for what purpose?
Use case should dictate design, not just some unfocused desire to make a thing.
List what it is to be able to do. That won't compromise your IP, and since multipurpose devices will suck at most tasks you can get some input on how to distribute the suckage to best advantage.
Consider multitools. They suck, but they suck less than not having a tool. Users select based on their personal task priorities. I for example most need pliers, cutters,knives and screwdrivers. A multitool can be with me when my shop is not, or at hand to save travel to get a tool.
>>936782 Very close to the same thing, slightly smaller 600 at harbor freight, wont have to get it shipped. Use the 20% coupon on it making it 480, you could try your chances and wait for it to go on sale and see if they let you stack it (some cashiers do some people dont) so itll be even cheaper
>>936782 the one thing I warn about these dinky lathes is that you should try to get one that you can get a 4-jaw (independent) chuck for.
first off, some info: 1) a "scroll" chuck is one where all the jaws move in and out at the same time, when you turn one screw on the chuck. Most like this have 3 jaws, but you can get 4-jaw scroll chucks too. 2) an "independent" chuck is one where each jaw has its own adjustment screw, and you must center parts manually. Most like this have 4 jaws, but you... Comment too long. Click here to view the full text.
Could you please suggest a simple finishing schedule to me for my walnut chandelier. I want it to be a very dark but be able to still see as much of the grain as possible. And would you be so kind to include the drying time I need on each step? And could you please suggest products that won't take very long to cure/dry?
Just a quick note I must add:
I already tried to finish this slab of walnut using BLO, then Watco Danish oil, dewaxed shellac and crystalac grain filler but somewhere I messed up and the piece turned not so very great. Some spots seemed... Comment too long. Click here to view the full text.
1/3 polyvarnish (matt gloss depending on finish) 1/3 tung oil 1/3 thinner mix it up. First coat apply thick leave ten and wipe leave to dry for 24 hours, light sand with 320, thin second coat leave 24, sand, third coat. Tada
So what's the deal with cell phone boosters/what experience do y'all have with them? I'm in the US and inside I have around -110dB signal inside (enough to ring the phone, but not actually talk on it), but outside I get around -80dB (according to my phone). I can't go the easy microsite route because I have to use satellite internet, but from what I'm reading one of the repeater styles should work decently well for me (at least well enough to use my cell phone inside). The biggest thing I'm curious about beyond which are the best (I'm on... Comment too long. Click here to view the full text.
My battery type is out-of-production and I let two of my three batteries freeze (d'oh). My drills see heavy use in between sitting. I like a small light drill with good balance. Looking for Hobby pricing with Pro performance. Don't want kits and don't care about having a dozen "tools" that use the same battery- just a good racheting drill and a driver drill. Looking for batteries that last forever. I've had my current setup for 10+ years.
What's good these days for a cordless drill and driver (separate)... Comment too long. Click here to view the full text.
>>936675 >Looking for Hobby pricing with Pro performance. >Looking for batteries that last forever.
You be looking long time, anon. I've gone DeWalt 18v XR (Li-Ion) - which aint really a recommendation either, just, bound to be a few things in the range (what you dont need today, you will tomorrow, etc.) - bare (no batteries) tools are cheap, and, currently looking at OEM batteries for these, if anyone tried any/got any recommendations? Otherwise, carry on..
Milwaukee M18 drill/driver combo. Tool stores will sometimes have specials where you get a free battery if you buy a bare tool. The trick is they want you to pay way too much for a charger. Buy a charger and extra batteries on Amazon.
This topic is annoying as fuck. I get into this every other year or so and it always end the same. I get about 2 weeks in and can no longer tolerate how shitty the tobacco is. Always had that dry, stale flavor and feels /tastes acidic on the tongue. It is disgusting.
Would love to hear some recommendations on tobacco to buy, preferably with comparisons to common standard cigarettes flavors. Just saying "it's pretty good" or "it ain't bad" tells me nothing.
>>937951 At least where I live, there is a legitimate honest-to-god pipe shop (as in, no "tobacco" water pipes [totally not for weed, guys, seriously], no paraphernalia or other dumb stoner shit) that will sell you bags of fresh tobacco just like a coffee shop will sell you coffee beans.
so i have found myself in the need of 7 small child sized looms. and wile looking online i found that the average price is around 110 -120 USD. for pic related style. for the production of scarves. around12-8 in by 6 ft. now that would take far to long to recoup the cost from that initial investment so i was thinking i would put my armature woodworking skills to the test. and wile i was searching the internet for plans i found myself flooded with how to use a loom or even loom documentaries without being able to find proper plans for one. so i was wondering if you guys knew... Comment too long. Click here to view the full text.
>>936661 I'm not really seeing the need for plans. Granted, I don't know that much about weaving, but from what I'm seeing, you could easily make something like in that picture with some dowels and small cuts of wood...what is it you're unsure of being able to make?
A pen exploded in my backpack a while ago (about 6 years ago) and it is high time I clean it. How can I get the stain to not bleed? I don't actually care about the stain, I just don't want it to rub off on anything.
Complications are the fact that it exploded in the tiny pockets in the front pouch so I can barely fit my fingers in there to scrub it.
So far I have put a lot of laundry stain remover and run it through the the laundry like 10x. Now it doesn't bleed unless I put stain remover on it and let it soak for a few minutes and try rubbing with... Comment too long. Click here to view the full text.
My bike started cracking around the seat tube since the top part of the tube is slightly smaller in diameter than the rest of the tube, which means that only a small part of it makes contact with the seatpost.
I've been trying to look around for people to weld it but haven't found anyone that I trust with it.
Should I just fix it myself? my idea is to cut the portion of the seat tube that is a smaller diameter and insert a new piece of seat tube in which I can then bolt or rivet in.
>>936640 Make sure they strip the paint and clean the metal good. A tig welder should be able to tmdo that for like 50 or 75 to 100 bucks depending on how good they are. They should also be able to level the weld off so you never even knew it was there.
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