[QUOTE=Gulen;39774286]Grabbed my arduino and two speakers and started messing with them today. I know that I was going to test something, but then I started to mess around more and more, and now I've forgotten completely what I wanted to test out... Anyways, I'm thinking about making an amplifier, after I fried my last one... (it was old and probably had a bunch of dust) I've missed having a use for my speakers and my sub...
I'll need an AUX input, two/three RCA inputs (not sure yet), and of course a selector for all three/four inputs. I think I've already got a transformer and connectors for the speakers, which I think I'll manage to salvage from the old amp. (the Sony amp I used has it's own connections on the back, and I have cables to match it)[/QUOTE]
Designing audio amplifiers can be quite a complex task if you want to make it from scratch, and an Arduino isn't going to cut it either. I suggest you check [URL="http://www.diyaudio.com"]www.diyaudio.com[/URL] for more info on DIY amplifiers. First of all though, you should make your mind up if you're going to use an IC (easiest, but not a lot of output power), or going for a class A, AB, B or D amplifier.
Am I correct that when using a 9 v battery with an Arduino, that once the battery gets to the lowest voltage an arduino can work at (5 volts) it has only expended about half of its energy powering the arduino? And if that is correct, isn't this wasteful?
boardless electronics.
I'm pretty sure repair shops everywhere were happy when the PCB came along.
[QUOTE=duno;39779306]Am I correct that when using a 9 v battery with an Arduino, that once the battery gets to the lowest voltage an arduino can work at (5 volts) it has only expended about half of its energy powering the arduino? And if that is correct, isn't this wasteful?[/QUOTE]
[img]http://www.mpoweruk.com/images/discharge-chemistry.gif[/img]
Maybe this will help you. Batteries usually have a relative constant voltage range per cell (9V batteries are just a couple cells in series, adding up the voltage), which then sharply falls off when the battery is almost completely discharged. So when your arduino turns off, you actually have almost completely discharged the battery.
Also you have to take into account that the voltage regulator on the arduino is a linear one, which means that you additionally loose 1.5V or so over it. So if you want to power your 5V Arduino with a battery it should have atleast 6.5V for the input voltage.
[QUOTE=JohnD;39778479][url]http://www.reddit.com/r/techsupportgore/comments/19db1d/took_the_backing_off_a_fulltone_intercom_is_this/[/url]
[img_thumb]http://i.imgur.com/uTt63REh.jpg[/img_thumb]
[img_thumb]http://i.imgur.com/W9gUAa5h.jpg[/img_thumb]
[img_thumb]http://i.imgur.com/ZdGrJivh.jpg[/img_thumb]
[img]http://i.somethingawful.com/forumsystem/emoticons/emot-stare.gif[/img][/QUOTE]
You know it's good engineering when it looks like this.
[QUOTE=Chezburger;39781716]You know it's good engineering when it looks like this.[/QUOTE]
Apperantly I'm a good electrical engineer then, or just a cheapskate.
I need a place where I can get a fuckload of perfboard/veroboard/stripboard for cheap.
[QUOTE=Van-man;39782612]Apperantly I'm a good electrical engineer then, or just a cheapskate.
I need a place where I can get a fuckload of perfboard/veroboard/stripboard for cheap.[/QUOTE]
Why don't you just make your own pcb's?
[QUOTE=Van-man;39782612]Apperantly I'm a good electrical engineer then, or just a cheapskate.
I need a place where I can get a fuckload of perfboard/veroboard/stripboard for cheap.[/QUOTE]
Ebay. Always ebay.
[QUOTE=Chezburger;39781716]You know it's good engineering when it looks like this.[/QUOTE]
Reminds me of an A/C system we replaced at a church recently. First one we replaced had a few extra relays and a feeler-bulb thermostat in it, and all of that had to go into the new unit. But the new unit had much less room inside once the hard-start kit was installed.
So I had to make notes on where all the wires and shit went (a surprising clusterfuck for how few extra parts were put in), but by the time I got done squeezing it all into the new unit it looked like a clusterfuck still, so I assumed I did it right. :v:
[sp]I did BTW, nothing asploded and it worked just fine.[/sp]
[media]http://www.youtube.com/watch?v=pjrPbGglEpQ[/media]
Feeding 15 volts thru a 10 ohm 0.25W dealextreme resistor. Bitch died on me on the second run.
I think you got a bit high on the fumes
[QUOTE=alexaz;39783874]Why don't you just make your own pcb's?[/QUOTE]
Often a shitload of work required for just a prototype, and getting PCB's made-to-order either takes a shitload of time, or a shitload of money.
[QUOTE=alexaz;39784610]Feeding 15 volts thru a 10 ohm 0.25W dealextreme resistor. Bitch died on me on the second run.[/QUOTE]
Now I know what to use that one 10W 30 Ohm I have laying around for.
[QUOTE=Van-man;39785399]Often a shitload of work required for just a prototype, and getting PCB's made-to-order either takes a shitload of time, or a shitload of money.[/QUOTE]
Prototype on the breadboard, then make the final boards. It doesn't take too much time, the process takes around 15 minutes for me and a dual sided 20x30 cm board costs 6$.
[QUOTE=alexaz;39785450]Prototype on the breadboard, then make the final boards. It doesn't take too much time, the process takes around 15 minutes for me and a dual sided 20x30 cm board costs 6$.[/QUOTE]
breadboard doesn't like high currents, also I tend to max breadboards out quickly if I don't divide my circuits up in segments and put 'em on perfboard.
[editline]3rd March 2013[/editline]
Breadboard is only good for checking [I]"will this shit work?"[/I] and that's it.
[editline]3rd March 2013[/editline]
And I also usually go though around 3 revisions before I finally have a circuit that's truly worthy of a dedicated PCB.
[QUOTE=Van-man;39785550]breadboard doesn't like high currents, also I tend to max breadboards out quickly if I don't divide my circuits up in segments and put 'em on perfboard.
[editline]3rd March 2013[/editline]
Breadboard is only good for checking [I]"will this shit work?"[/I] and that's it.
[editline]3rd March 2013[/editline]
And I also usually go though around 3 revisions before I finally have a circuit that's truly worthy of a dedicated PCB.[/QUOTE]
I usually make my first or second revision on padboard. If it's something I'm not sure if it'll work I'll breadboard it first, otherwise just build it up first go. Only if it's something I want to make more permanent do I bother with a real PCB, most of my projects are just one-off gadgets or prototypes where I can't be bothered.
Fuck breadboards. Sheets of bare pcb and soldering straight on it.
Just like this
[img]http://kd1jv.qrpradio.com/ARRLHBC/board3.jpg[/img]
[QUOTE=Chezburger;39786489]Fuck breadboards. Sheets of bare pcb and soldering straight on it.
Just like this
[img]http://kd1jv.qrpradio.com/ARRLHBC/board3.jpg[/img][/QUOTE]
Yeah I do this a lot, particularly good for RF or low noise.
[QUOTE=DrLuckyLuke;39784794]I think you got a bit high on the fumes[/QUOTE]
Am I the only one addicted to flux fumes?
[URL]http://www.elecfreaks.com/store/flowerpad-noplated-protoboard-225x68mm-p-388.html[/URL]
Quite spicey pricetag, but it's also got some spiffy features for making SMD prototyping a tad bit easier.
Wondering about how legal it would be to copy the layout (read: buy one and scan it) and then have a stack of them made to my size and specifications.
[QUOTE=Chezburger;39786489]Fuck breadboards. Sheets of bare pcb and soldering straight on it.
Just like this
[IMG]http://kd1jv.qrpradio.com/ARRLHBC/board3.jpg[/IMG][/QUOTE]
There's a small voice in my head screaming [I]"NOPENOPENOPENOPE"[/I]
I guess it's my otherwise dormant sense of neatness & order.
Oh, and in other news I just ordered a Raspberry Pi.
How do you insulate it? Cut the copper with a knife?
[QUOTE=alexaz;39786738]How do you insulate it? Cut the copper with a knife?[/QUOTE]
AFAIK some people use a dremel with a small grinding tip.
Can also buy a hollow drill bits to create "islands" on the pcb.
[QUOTE=alexaz;39786738]How do you insulate it? Cut the copper with a knife?[/QUOTE]
Usually the copper is used as a ground plane, all other connection are made point to point.
Very much like most vintage electronics.
[QUOTE=alexaz;39786738]How do you insulate it? Cut the copper with a knife?[/QUOTE]
You usually just use it as a big ground plane. For RF it's great, you don't get as much paracidic inductance and capacitance from the tracks etc.
edit: Chryseus beat me to it.
Is there a cheaper alternative to carbon paint?
The contacts on a rubber dome keyboard died and I need something I can paint on the old contacts to restore them.
Carbon paint sound sliek it would work but it's super expensive.
[QUOTE=MIPS;39789886]Is there a cheaper alternative to carbon paint?
The contacts on a rubber dome keyboard died and I need something I can paint on the old contacts to restore them.
Carbon paint sound sliek it would work but it's super expensive.[/QUOTE]
I suppose you could also try buying some hobby copper foil at a hobby store, cut it to size and glue it to the rubber membrane.
[QUOTE=MIPS;39789886]Is there a cheaper alternative to carbon paint?
The contacts on a rubber dome keyboard died and I need something I can paint on the old contacts to restore them.
Carbon paint sound sliek it would work but it's super expensive.[/QUOTE]
Circuit-writer pens, maybe?
Why not just make pcb's by taking a piece of wood, hammer in some nails and mount the parts between the nails? Yes, I actually did this to make my crystal receiver back in tha day.
[QUOTE=Chezburger;39792392]Why not just make pcb's by taking a piece of wood, hammer in some nails and mount the parts between the nails? Yes, I actually did this to make my crystal receiver back in tha day.[/QUOTE]
Back when a breadboard was a ....breadboard.
[img]http://tangentsoft.net/elec/bitmaps/ab0cw-breadboard.jpg[/img]
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