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4666  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: please help designer on: August 31, 2010, 10:16:09 am
and switched on manually

This would probably be the point of failure - people aren't going to want to switch on two buttons for use of an appliance or whatnot...

What would be more likely used (from the point of view of a package to buy for a house or office) would be a "dongle" the device could plug into (which would pass-thru current and the dongle would transmit that "it was in use" for the appliance) or a wrap-around current sensor on the plug/wire that could do the same thing. Transmission would be wireless (or via the powerlines, like X10 - in the case of the dongle), and each device would have an address (tied to the appliance or lamp). Certain appliances (like the A/C unit, water heater, oven, etc) would need this extra device professionally installed on them (or, since most of these appliances would be on their own breaker, installed at the breaker box).

This still doesn't code for the user using them; one way this could be done (least intrusive) might be for the device to sense and read an RFID tag on the user (integrated into say a ring, watch, bracelet, or other bit of jewelry, perhaps). The only problem would be doing this and keeping the device reading it (and integrated with the dongle) compact, yet still able to read the user (and this wouldn't work with certain appliances - like a hot-water heater; perhaps these would just have to be implemented as "global" - otherwise you would need to integrate things with the plumbing, too!).

This is a very complex project - doable, certainly; maybe even with Atmel processors (not necessarily the Arduino, though - except for prototyping). I don't think these devices should necessarily consume more power than they save (although what do I know - I haven't been an electronics engineer for 40 years!  smiley-wink ) - but at least some of these devices might have to be powered by batteries (unless you want cords or custom wiring done), which may or may not last thru the month (and the cost would have to be figured into the system).
4667  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Score!!! on: August 29, 2010, 07:09:11 pm
Cr0sh what is wrong with AM radio's? i wanted to make a Rugby time signal radio, they would have been useful

I am not sure if I was specific enough - these chips I have are AM radio receiver chips; basically a bog-standard AM radio on a chip (some external parts still needed, though).

Inherently, there's nothing wrong with these chips, if you have a need for them; I personally don't for my interests, but that doesn't mean somebody else wouldn't...

4668  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Score!!! on: August 28, 2010, 07:18:00 pm

Heck, that's nothing. A long while back I purchased a whole tub of various ICs in various ranges of "quality" (ie, some were smashed bugs, others were brand new). I went through the entire bin, and only about a month or so ago did I finally get everything completely sorted (there was also miscellaneous transistors and other small components mixed in).

Best thing to do is just jump in and start sorting. Put on a static strap first; most older TTL devices are ok handling in general, but CMOS stuff can be fragile. Depending on how you want to sort and store them, you might look into getting some anti-static foam to stick 'em into. You might want to get some parts bins, or do the plastic baggie thing.

Be aware that some parts you may not be able to identify. Put those into a ??? pile and move on; come back to them later. Google is your friend; look up datasheets, and save them in an archive as you go along (I typically keep a copy of every datasheet I run across - even if I don't have the part, maybe in the future I will) - note that in your inventory as well.

Some parts may be "house marked" - that is, they were numbered by the manufacturer for the company that bought them; good luck figuring them out! Depending on the numbering scheme it may or may not be possible.

It sounds like you have a big task ahead of you; it may take a while, but you'll get there.

A few things to note - if any of the ICs have gold leads, are made of white ceramic, or have windows on top, you may want to set them aside. Gold leads can indicate mil-spec parts; white ceramic can indicate similar, or other "specialness", and if there is a window, it is likely a UV-EPROM device.

Some UV-EPROM sizes and types are sought by collectors and restorers of old arcade machines. If you have such a device, and there is a label over the window with hand-written wording - leave the label in place (and if you have more than one, and can identify a set - keep those together). Such EPROMs store code and data, and depending on what they were for, might be worth more (ie, its software for an old embedded system) than the chips alone. Of course, it has to be the right software (old arcade romsets are highly sought). You want to leave the label in place so that any code doesn't get corrupted by light exposure (although depending on the age and other such factors, it may or may not matter).

But first, identify all the chips - you should keep as many as you can, as long as you think they are something you will use (for instance, from my pile I found several AM radio chips - basically an AM radio on a chip - I need those like I need a hole in my head). I would keep any op-amps (especially if it is an instrumentation amp!), audio amps, comparators, digital logic, etc - those are all useful.

Good luck, and have fun - I can't wait to see what your haul included!

4669  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Score!!! on: August 28, 2010, 03:20:32 pm
Ok - something found or given?

My brother-in-law was working on a job on the other side of town; he told me he had seen a bunch of computer junk next to a dumpster behind a taco shack...

We drove over there, and I managed to collect two Apple IIgs computers (one missing its top cover), a couple of Apple floppy drives (on 3.5 and one 5.25), a mouse, and various cards, plus keyboards. Not too bad of a haul for free.

I ended up taking them home, and booting up a 15 year old copy of Battletech I had for the Apple IIe - I had to use a small 5" portable color TV for the monitor...but they worked fine!

4670  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Score!!! on: August 28, 2010, 03:16:31 pm
Well, I had to pay for it, but I'd say the best thing "given" to me was my Altair 8800 (with more peripheral and memory cards than the bus could hold).

And by "pay" I mean I spent $100.00; the guy at Apache Reclamation was firm on the price, and wouldn't budge (I offered $50.00...) - he told me "some guy pulled it out last week from that trailer over there (pointing to the trailer behind it) - and told me it was an antique. $100.00"...

Yes, it was difficult to part with that hundred - I think I laughed all the way home.

After doing a bit of research, I found that mine has the rarer toggle switches (round handle instead of flat - IIRC, most were made with flat toggles); that night, I posted about it on a small Altair list, and was immediately offered a considerable sum more than what I paid for it. I declined; I intend to someday restore it to museum display quality if I can. It needs a lot of TLC, though...

4671  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Etch your own circuit board. (lots of pics) on: August 21, 2010, 07:59:07 pm
Something to note: Don't put the ferric chloride in any metal container, or use any metal instruments, or dump it down a metal sink or metal pipes (not that you should do the last two at all!). Ferric chloride will eat up all that stuff, and it stains badly - really bad stuff.
4672  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: How to distribute on: August 26, 2010, 12:35:49 pm
Note there there is literally NOTHING in an Arduino- it is a concept rather than lots of hardware.

A better way to phrase that would be that the physical Arduino (Duemilanove) is a design for a carrier board for the ATMega8/168/328 microcontroller.

4673  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Vacuum sensor for automotive assisted brakes on: August 23, 2010, 02:22:43 pm
..right up to the point that some jerk with failed brakes and invalidated insurance drives into the back of you at lights.

If you're lucky! You might be t-boned at an intersection; though in the UK it might "sideswiped on a roundabout" (wish we had more of those here in the US).


GordonEndersby: It sounds like you know what you are doing, but please be careful. I know that the booster is only one section (and is there to help - not replace - so pump the pedal if you have to, I suppose!). If you can make it as safe as possible, and it won't invalidate your insurance...

Well - good luck with finding the problem!

4674  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Vacuum sensor for automotive assisted brakes on: August 21, 2010, 04:33:21 pm
Ide like to add a t-piece to incorporate the sensor and monitor the vacuum for variation over time and failure.

So you want to "break" the vacuum system, and in effect, introduce four new points of potential failure - for your brakes on the car you drive?

I say four, because now you would have the three joints on the T-connector, plus the sensor itself - as new points of failure; and it doesn't sound like you are even sure it is the vacuum line or pump...

This doesn't sound like the safe thing to do. You don't mention what your problem is exactly (what you are experiencing), but if this was my situation, I would remove the line from the booster, and put a vacuum gauge on it, run the engine to pull the vacuum (via the pump), and see if it compares to what the manual/specs says it should be.

There's probably even a testing procedure outlined in a Haynes/Chilton; likely you run the engine to draw the vacuum, and the shut it down to see if the vacuum holds over time. If it doesn't, then it is the hose or the pump. If it does, then it may be the booster. Depending on the age of the vehicle, you might just want to go ahead and replace all of it.

Its your car, and your risk, of course - but I would definitely think long and hard about messing with the braking system of your vehicle (and potential consequences of doing so)...
4675  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Help getting started on: August 20, 2010, 10:24:13 pm
I'd really like to know how this whole "meme" of the Arduino "not using C/C++" got started. I'd also like to know why these people parrot this stuff, when it would be fairly easy to check it out for themselves and see that the avr-gcc compiler is invoked. Finally, it irks me that people think of the Arduino as a toy or worthless or something; like somehow it is impossible to code for the ATMega168/328 in "straight C" (like any other AVR) or even (boo! j/k) assembler - then upload the resulting hex file with a programmer via ICSP. I think maybe most of the people are ticked because an open-source community has made microcontrollers easy to use (similar "hate" was directed toward the Basic Stamp series, too)...

4676  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Maze Solver on: August 23, 2010, 02:08:49 pm
Hmm - you might actually think about approaching this problem as a machine vision problem.

If you have a white floor and black walls, it is a perfect high-contrast situation. You would need to image the path in front of you (so, in a 2D perspective, it would look like a "thin triangle") - paths left and right would appear as thin lines leading left and right. A T-junction would look like a T, etc...

Basically, with the right coding, you would be able to tell that a certain path might lead to a dead-end without having to run down the path; you could give a particular branch node point probabilities that the branch leads to a dead end. At such nodes, the robot would scan and look at all directions and give weights to the paths it hasn't visited (and keep track of ones it has or has passed).

I would think approaching it in this manner might give a faster solution to a random maze, rather than what would essentially be a "blind maze runner" with "bump sensors".

The issue then would be to find a means of interfacing a camera to the Arduino - not an easy task. I think for this I would look into interfacing either a CMUCam (or similar camera with on-board processing to reduce the data load to the Arduino), or maybe use a small, low-res camera device like that on an optical mouse. You don't need to store the image data, just start and end points for each scan line (after simple filtering for contrast and noise) to determine the floor layout...

4677  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: I need something to give me a pulse. on: August 17, 2010, 09:43:06 pm
Once you're dead, you're dead man...

/get the paddles...CLEAR!

4678  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: The new guy has a question!! on: August 20, 2010, 06:15:38 pm
I'm not going to push a kit or something like that, but I think you'll find the Arduino more to your liking for Linux.

I started out a project using a Basic Stamp 2 I had lying around; for me, the coding wasn't an issue (I grew up on BASIC), but I was kinda wary that Parallax only provided a bytecode compiler for the Stamp series under Linux as a binary, with no source. At the time, I thought "well, somethings better than nothin'!".

When I decided to upgrade my system to a 64-bit box (ubuntu, BTW), that's when I hit a brick wall with the Stamp.

Their bytecode compiler wasn't just a binary - it was a statically-linked binary! That meant there was -no way- to use it on a 64-bit box; it would only work (at best) on a 32-bit box. Nothing possible could be done on a 64-bit box to get it to run (like IA32 wrappers). After discussion with Parallax, I learned that they weren't going to update the compiler, because they didn't have the source code, they lost contact with the original programmer (who had the source code), and didn't really seem to care about the product (Basic Stamp 1 & 2, at least) because it was being EOLd (in favor of the SX and the Propellor). They also didn't seem to give a darn about Linux users.

Oh well. I ended up looking around, and somehow happened upon the Arduino. I honestly couldn't be happier with the decision. Some may tell you "well the Arduino isn't a real microcontroller" or some other such nonsense; there seems to be a lot of people in the PIC world who think if you program in something higher level than assembler, you aren't getting the most out of your chip. I can't completely argue against that, having some experience with assembler, but really, I think they're approaching it from the wrong way (the proper way to write any application - whether for a microcontroller or a PC or whatever - is to first diagram and design the application, then code in whatever language suits you for that application; the higher-level the language, the better. If you find areas where you need speed increases, look toward the inner loops in those areas, and fix those, then work outward. If you are still facing issues after those optimizations, look again, and see if you need to tighten up the code, or develop those areas in lower-level code (check to see what opcodes your compiler is spitting out - maybe you can do better, depending on the compiler, and what optimization flags you have set - or don't!).

Ultimately, approaching such applications from the bare-bottom-up, on a microcontroller, from assembler, can really turn into the "wrong way" to do it. You might get it done, and it might work fast, but unless your only eatin-n-drinkin' is in assembler, you likely will be able to get something working faster using a higher-level language. This becomes especially true if you are doing the coding for a client; they don't generally care what you work in, or that it is "blazing fast" - first and foremost, they want something to work, then worry about speed and other issues. Steak before sizzle, ya know?

The Arduino (well, really the ATMega) is just as much a microcontroller as anything else. Think of the Arduino as actually a "carrier board" for the ATMega - that's a terminology you might be familiar with from Parallax products. Sure, it has a bootloader to make things simpler, so you don't need a fancy programmer or anything to start off with. I think that's a great thing; others look down their noses at it. Not that it can't be used (you can ditch the bootloader, gaining back 2K of program space, and use a real programmer with the Ardunio and IDE if you want - if you really want, you can go all AVRFreak and drop the IDE as well!)...

Welcome aboard. As one Linux fan to another, I hope the Arduino turns out to be fun for you like it has for me.

4679  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Software used to produce this (see topic) picture. on: August 18, 2010, 03:17:41 pm
I still want to know the software though... isn't simply curiosity reason enough?

Certainly! I would be interested as well, though I would likely never use such software (I would, however, use something like in Fritzing, where I could prototype a design on breadboard, then put the parts over onto fritzing's breadboard, and it would keep the netlist for the schematic, then to PCB - but then again, one should build the prototype on the breadboard from a prototype schematic - I just tend to hack something together on a breadboard first from basic schematics, then draw a real schematic, and update from there - probably a bad workflow, actually).

Just realize that while it helps you, eventually the training wheels need to come off...


Mowcius quietly dies.

Done properly, wirewrap can actually be a nice thing; the problem is learning to do it properly. I read a tutorial on this once, which involved wrapping the layers such that, for any pin with more than two levels, you would only need to take off a set of levels of some low number to reach the level you wanted.

Wire-wrap has its uses - it is a much stronger mechanical joint than soldering, for instance...

The "worst" rats-nest I have seen of wire-wrap (which probably isn't the absolute worst - I am sure some of the old transistor and older computers that used wire-wrap were real nightmares) was of something called the "CoCo 3 Prototype" - this was a wire-wrapped monster of a Tandy Color Computer 3 used by Microware to (supposedly) develop OS-9 Level II for the CoCo 3 back in the mid-1980s:

This is one side of it:

I can't find images of the backside, but let's just say its a mess; by the way, that board above is pretty large - it also doesn't have on it a chip that is on the CoCo called the GIME; this chip was a "proprietary" chip, and no more exist - it is thought that the GIME was implemented on this board using discrete logic ICs and/or custom programmed PALs or other such devices (before it was ultimately commited to fabbing as an IC). This was the way things were done back then...

4680  Forum 2005-2010 (read only) / Frequently-Asked Questions / Re: Software used to produce this (see topic) picture. on: August 18, 2010, 01:51:13 pm
It's me!  

I just want to know what is the software because this style of visualization is much better to understand imho. I don't plan to use the software as a substitute for real-life, but I don't want to risk my Arduino, so, at least for the firs tests, i'm gonna use a software and study very carefully every part of the scheme to avoid possible damage.

If a schematic or assembly diagram is displayed or drawn incorrectly, assembling it the same way won't prevent damage.

You need to learn to understand and visualize how a standard schematic relates to the assembly on your breadboard or on a real PCB. Not only that, but you need to know how to read a schematic to be able to assemble it on a board, as well as how to understand how and why parts are connected in the schematic (and their values) - to understand if a particular schematic handed to you is valid and will work, or will just completely fail (sometime spectacularly!).

A wiring diagram or assembly diagram can help, but recognize them for the training wheels they are, and learn to ride that bike properly, as quickly as you can!

Thank you.

PS: The frietzing wires rendering (poly-shaped) is not only boring, but also very confusing when lots of wires are near. (ihmo)

I think anything that shows a real physical layout is, in the end, going to ultimately look like a "rats nest" after a certain level of complexity. This includes even a PCB view; fortunately those can be set up to only display certain layers as needed, so it isn't so cluttered.

Fritzing's layout was probably chose to route as it does because normal jumpers for breadboards are straight wires (that are not supposed to be bent, period). It is possible to make a very dense board with many parallel "bus" lines, that is very easy to follow - provided one uses the same color of wires for the jumpers, color coding everything, in fact - along with proper layout (and leaving plenty of space - so many people cram way too much on a single breadboard, instead of spending the money on extra breadboards). Really, the flexible wire jumpers you see out there, while useful, seem to sometimes only serve to create more severe "rat's nest" wiring, thus causing further confusion.


/then there's wire-wrap...
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