Learning electronics: Release the Magic Blue Smoke

The Something Awful Forums > Discussion > Hobbies, Crafts, & Houses > Learning electronics: Release the Magic Blue Smoke

thepartypooper: Jul 4, 2002

I want to pick up a 2-line alphanumeric LCD to work with, since I've never touched them before. However, data sheets for these seem to be universally sparse; usually little more than a mechanical drawing.

I've come across a few that say they are Hitachi HD44780 compatible, so I've picked up that datasheet. Is this the case for most parallel LCD's? If the datasheet doesn't say otherwise, should I assume that this is the interface?

# ¿ Jul 25, 2008 20:03

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# ¿ Apr 28, 2024 14:04

thepartypooper: Jul 4, 2002

I vote for audio effects.

I'm learning about transistors this semester anyway and I'm not really interested in EagleCAD, but signal conditioning is always interesting.

# ¿ Sep 14, 2008 07:02

thepartypooper: Jul 4, 2002

jeremiah johnson posted:

I just bought an hp 1222a oscilloscope and it didnt come with a power cord. The socket for the cord fits a standard pc cord, is it safe to assume that would be the right cord?It also has a two switches for the line voltage they look like this
pre:
          
               Line Select
                240 120
                  |-| 
                  | |
                100 220
                   V 
                200 220
                  | |
                  |-| 
                100 120 
Does anyone know what the bottom one for?

I would expect that that cord should be just fine. It's a pretty long-running standard.

As for the switch, that's a little confusing. Are you sure either the 240 shouldn't be 200, or the 200 shouldn't be 240?

The only way I could make sense of it is if, for example, instead of 200 it said 240 on the lower switch. Then the combination of switches would specify the line voltage. For example, top switch down + bottom switch down = 100. Top switch up + bottom switch down = 120. Etc.

# ¿ Dec 19, 2008 00:39

thepartypooper: Jul 4, 2002

Corla Plankun posted:

My radio got stolen a while back, and I really miss it. I'm not keen on just replacing it with a new one, because it will probably just get jacked again.

SO, instead I would like to keep a big gaping nasty hole in my dashboard that says, "you already hit this one", and then hide a sound system somewhere else.

I have a really awesome Sansa mp3 player with FM radio, and the speakers in my car are really great. I just need some way to amplify it. Can I just buy a car amplifier at Best Buy or wherever and hook it up to the headphone jack on my Sansa? I feel like this would be too easy and there is more work to be done, so I am hesitant to try it.

It's almost that simple. The worst part of it will be running power for the amplifier. Since most separate power amplifiers draw a lot more current than your average head-unit, you won't likely get away with powering it off of the existing wiring for the stereo. You'll need to run a heavier gauge wire from the battery into the car, and another one to a good chassis ground. You'll want to put a fuse inline as well. You'd also need to wire up 12V (via a toggle switch or you can just use the switched 12V lead that used to go to the radio) to the remote turn-on lead of the amplifier.

Once that was sorted, all you'd need is a 3.5mm stereo miniplug to RCA adapter to plug it in.

The only problems I see with this setup is that, unless your MP3 player has really good bass/treble controls, you might find the system doesn't sound nearly as good as your old stereo did. In my experience, the range of adjustment of most MP3 players is pretty limited, while a head unit needs to be very adjustable because it's designed for an environment that has a lot more variables in it than would a set of headphones coupled directly to your ears.

# ¿ Dec 19, 2008 01:04

thepartypooper: Jul 4, 2002

Zaxxon posted:

...after that I wipe the iron off on a damp sponge and then I solder things, wiping the Iron down a bit when I'm not using it directly (usually once every couple of minutes.)...

This might be your problem. Are you leaving it tinned while it's sitting idle? Or are you wiping it down periodically, leaving it bare? You don't want it to sit there hot with no solder on it, that's when the tip can oxidize.

If you're not already doing so, make sure you melt some solder onto the tip after each time you wipe it.

# ¿ Jan 24, 2009 09:26

thepartypooper: Jul 4, 2002

As mentioned above, sparkfun has a few different surface to dip adapters.

You could also check out Schmart boards: http://www.schmartboard.com

# ¿ Jan 25, 2009 05:02

thepartypooper: Jul 4, 2002

clredwolf posted:

-"Opamps for Everyone", Mancini

From reading one of the reviews on Amazon, it turns out this book is available for free:

http://focus.ti.com/general/docs/techdocsabstract.tsp?abstractName=slod006b

Looks pretty good so far. Kinda wish I had this at the start of my analog class this semester.

# ¿ May 11, 2009 23:02

thepartypooper: Jul 4, 2002

I'm running into a problem using the SPI interface on a PIC32. Looking through the user guide and the peripheral library guide, it doesn't look like it supports the configuration I need.

I need to set it up as the master, and hold the slave select line low for the duration of the write (like the timing diagram here). What I'm finding is that it has 2 modes for master operation: normal, which doesn't use the slave-select line at all, and framed, which pulses the line at the start and end of the write (pictured below).

I know I could just bit-bang it, or use another IO for the SS (which raises other issues as far as synchronizing it with the TX frame), but I figured maybe I'm overlooking something. Anyone have any experience using SPI with this part?

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# ¿ Jun 19, 2009 08:33

thepartypooper: Jul 4, 2002

BattleMaster & Zuph posted:

use another io

I've actually tried this like so:

code:

PORTClearBits(IOPort_A, BIT_0);
SPI1Write(0xaa);
PORTSetBits(IOPort_A, BIT_0);

but I end up with this:

code:


SS:   -----________------
Data: _________-_-_-_-___

At least with the current peripheral clock that I'm running, the SPI is still writing when the GPIO pin goes high. I know that it's probably not that sensitive, but I don't expect it to be as forgiving as to have the SS signal offset by half the TX frame.

FYI, this is what I'm trying to program: AD9833

From looking at the PIC library guide, there doesn't seem to be an easy way of testing if the SPI is done transmitting in order to easily use an IO pin in this way.

# ¿ Jun 19, 2009 23:08

thepartypooper: Jul 4, 2002

I think that's what I'll have to do. I had seen that flag on the datasheet, but it doesn't seem to be exposed in the peripheral library. It seems like a strange omission to me.

thepartypooper fucked around with this message at 23:33 on Jun 19, 2009

# ¿ Jun 19, 2009 23:31

thepartypooper: Jul 4, 2002

BattleMaster posted:

I've honestly never used PIC32s, but the lower-end pics like the PIC18 series each have a header file that allows you to access registers and bits in them as if they were variables. For example, for a PIC18F4550 I need to include p18f4550.h and to loop until an SPI transmission is complete I can do something like

while(!SSPSTATbits.BF)

I bet you can do something similar with PIC32s. It would be pretty messed up if you could only use a premade set of libraries to interact with the I/O on the thing.

Cool, I'll look into that. Thanks!

# ¿ Jun 20, 2009 00:18

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# ¿ Apr 28, 2024 14:04

thepartypooper: Jul 4, 2002

I have this station: Hakko 936

When I bought it, I'd also been looking at the Weller WES51, but most of the info I could dig up pointed to this being a better station.

I've been very happy with it. It heats up fast, maintains temperature very well and there's a good variety of tips available. I got mine on ebay, but Amazon seems to have it cheaper right now.

Edit: If you order one, check to see which specific model number it is. There's 3 different ones (Hakko USA) with different irons. I've got the medium one, and it comes with a wedge tip that's pretty well suited to general purpose soldering, though not necessarily for really fine pitch SMT components. Plus the nice thing in my case is that the local electronics shop stocks tips for it.

thepartypooper fucked around with this message at 23:46 on Jun 20, 2009

# ¿ Jun 20, 2009 23:25

The Something Awful Forums > Discussion > Hobbies, Crafts, & Houses > Learning electronics: Release the Magic Blue Smoke