For sale.Cold fusion reactor.Home made.Not working.$2000 ONO

westaust55

Moderator
Some forum software uses quotes to tell the user that their comment has been responded to.

I've found that . . . . . sometimes threads can be so busy that by the time you finish typing a reply, another post has been dropped in.
This can lead to a stack of confusion and people taking offence.
While you can certainly use quotes here as you already do, another option is to just address that person with @<members forum name>.

It is also possible to address more than one person in response to various posts in this way similar to using the forum multi-quote option.
In this case a post might be in the format:

@Tom,
response1

@Dick,
response2

@Harry,
response3
 

westaust55

Moderator
If I have parsed the above correclty, this thread will be tangentialising onto fluid queries and wet plants - good luck team :)
Hmmm, with respect to this thread, "120" has stated on the Backyard Aquaponic forum:
"I plan on keeping all my posts in my first thread... "

I foresee this thread becoming akin to spagetti code with questions on program commands, circuits and wet "stuff", interspersed with other topics as thoughts arise.

Certainly folks here will help with answers but some organisation could be a good thing as well . . . . .
 
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120ThingsIn20Years

Senior Member
Thanks westaust55 and thanks to everyone else who has made this first part of my education so much better than it might have been.

I take your point about the thread, it has turned into a bit of a monster.

I guess this thread has been about me, and my education rather than anything more specific. I'll post questions elsewhere from this point on.

Thanks again for everyone concerned, it's been an amazing 22 day ride so far. I've learnt so much stuff in these last few weeks. Much more than reading this thread might indicate. Enough that I feel I can make stuff as desired, which is pretty amazing given my total lack of knowing anything about electronics only a few weeks ago.

I started this thread with a statement like "I could perhaps build a torch on a good day, but couldn't make it it turn itself on automatically when it got dark".

Well now I can, and if needs be I could do it only on the 29th of February, only if it's a warm night, and only if I'm wearing blue, and standing at a particular longitude and latitude.

That's some pretty pretty cool shi(p).

I owe you all a beer/cup of tea.

Thanks again.
yeah I covered that

As I said I'll post about my progress, but I'll respect peoples requests to gain some order, and I wont ask questions here any more.

No doubt I'll learn all about irritating people like me on the new electronics section of the aquaponics forum.

But as I said, I'll respect the request to not post questions under this title, and I'm pretty sure I have done so since saying it the first time.

Personally I like this thread, and I know other people do as well.

Most people that dont like it probably just dont read it.

In fact I would go so far as to say everybody other than moderators are reading this thread because they like it, or like to hate it. Either way I dont think it's done any harm, and it's certainly done me a lot of good.

I've just finished a bit of an introduction over at the aquaponics forum, so I think it's fair to say I'm only interested in learning and sharing PICAXE, and certainly have not done anything intended to upset anyone.

I'm really excited about this product, I'm not trying to sell anything, I'm trying to learn as much as I can as fast as I can because I love learning, I'm blogging about it, need to make stuff that I need to use in the real world, and because at my request, there is now a new section on electronics in the aquaponics forum, that I'm trying to get everybody else as interested in electronics as I am.

I thought all that stuff might be seen as a good thing.

I really didnt mean to upset anyone.
 
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Dippy

Moderator
I don't think anyone is upset. If it has been useful to you then that's a good thing.

The only thing I can think of that probably caused head-scratching was the impression that you are/were trying to do 120thingsatOnce i.e. not getting to grips with one thing before flitting onto something entirely different. That's how it reads to me.

It would be far better if you concentrated on one thing at a time and nailed each section. A thread for each (different) enquiry, then you will learn properly. Spend a little time having a real go. Do some experiments, make some notes, make some mistakes, make some discoveries and do some research for yourself from good sources .... then it'll sink in.

Just remember; people here like to help but sometimes lose interest when it all starts meandering.:)
 

120ThingsIn20Years

Senior Member
@westaust55

I just started playing with Pebble, and thought I'd just say thanks for it :)

I'm using it to work out veriboard layouts for the first time.

Each step of this education of mine is proving to be as tricky as the last :)

Thanks again.


And your PM folder is full.
 

120ThingsIn20Years

Senior Member
I thought I might just drop back in to my happy place and share my progress.

I've been a bit off lately so haven't been achieving as much as I would have liked, but just discovered that I can reuse pins as inputs and outputs. This very cool and has me excited about the possibilities in the final touches to my fish feeder.

The fish feeder PVC and actual feed delivery stuff works, and I even made a nice (I'm really proud of this for some reason) water proof switch for my bonus "FeedNow" switch so you can show a visitor the fish pressing the lever when the light somes on (ie it just overrides normal feed restrictions).

The software also works except for the section to increment time on the day scale, and the bit that checks for dawn to reset the day based on light levels. So basically, the software is finished except for the dawn reset and dividing the (roughly) 24 hours into the number of feeds the human sets for their maximum limit ie OneDay / MaxFeeds.

After that, all I have to do is rework a bit more code to get rid of some gotos (I only just (almost) got the hang of do loops) but most of that is done as well.

The board is also finished except for soldering on 3 pots and 3 LED's.

I'm down to one pin, so had to try to work a way to reset at dawn (calibrated with a trim pot), AND give some feedback as to the value the pot was set to via a flashing led. I decided to use BOTH the two other trim pot's LEDs flashing at the same time to indicate the dawn pot's value, but have since discovered the command INPUT b.4 which sets a pin used as an output to an input.

What this means is I could have used three pins for my pots and LEDS rather than the five I used, and I've just come up with a really nice way to give even better feedback to the user, and also force the user to set the pot in the centre of the range of each select case "bracket". I imagine that there could be a situation where the user sets the pot right on the line between two "select case" values, and as a result slight temperature differences or magnetic fluctuations or battery* strength etc could see it wandering across the boundary into the next value.

So I figure I'll be a few more weeks depending on my state of health (morphine patches make brain go bye bye)

So for anyone who cares, I'm still here and making progress.

This stuff is amazing and I had no idea what I'd be able to do within such a short period of time.

The other day I opened my broken digital TV HDD recorder because I thought I might notice something wrong. The first thing I saw was a large cap with a swollen end. I doubt I would have noticed it 2 months ago because I would have known that caps dont normally look like that. I've ordered a new one and hope to make my first ever repair (I got some good safety advice from the electronics shop). I'll be pretty amazed if it turns out to be all that's wrong with it, but if it is I would have saved a few hundred dollars for five bucks, and Mrs 120ThingsIn20Years will finally see the value in this electronics caper :)


As usual thanks again for all the endless support within this thread and the ongoing answers in other threads.


*must write the code to set a base value for battery strength and some kind of low voltage warning.
 

John West

Senior Member
A bit of warning: Electrolytic capacitors often simply die on their own account. But other times they get killed by a rectifier diode that has shorted out and is allowing AC to reach the capacitor. Therefore, it's a good idea to resistance check any rectifier diodes that feed such capacitors, before you risk popping the replacement cap as well.
 

fritz42_male

Senior Member
Although electrolytics can fail, a LOT of manufacturers have been suffering from counterfeit ones. I recently repaired my HP all in one printer which kept on giving me 'ink system has failed' messages. A lucky Google search told me what to look for and 4 capacitors ($10 worth) and 20 minutes had a working printer again.

Now although the printer is out of warranty, I find it reprehensible that the manufacturers don't 'come clean' about such problems as it is their responsibility to ensure a clean supply chain.
 

120ThingsIn20Years

Senior Member
Although electrolytics can fail, a LOT of manufacturers have been suffering from counterfeit ones. I recently repaired my HP all in one printer which kept on giving me 'ink system has failed' messages. A lucky Google search told me what to look for and 4 capacitors ($10 worth) and 20 minutes had a working printer again.

Now although the printer is out of warranty, I find it reprehensible that the manufacturers don't 'come clean' about such problems as it is their responsibility to ensure a clean supply chain.
Oh great! I didn't even know I had to worry about counterfeit parts :)
 

120ThingsIn20Years

Senior Member
I only recently started wearing shorts.

No really :)

My problem was I had a dad who wore safari suits and would say words like "cobber" when buying beer from a drive through.

It's taken a lot of therapy, but I can finally wear short pants.
 

120ThingsIn20Years

Senior Member
Hello 120 things,
Great subject line! ...I was expecting a homage to Dr's Flieschmann and Pons (spelling??).. all this for just $2K?-- Bargain.

I am located in Adl and may be able to help you.

Not sure how to contact you directly, does this forum support Personal Messaging?

I have a fair bit of experience in using the Picaxe and some other micro's to control and monitor things, all the way from 40 odd lines of code with an 08- to needing the 40 pin devices to fit in all the wild ideas and drive all the wiggly bits.
I design high end valve audio gear and have 30+ years electronic and IT experience.
(Just establishing credence, not wanting to sound like a smart-alec.)

You are on the right track in using the Picaxe, it is a piece of cake to knock-up a prototype and the programming tool Progedit, with the debug and simulation features makes life a whole lot easier than trying to do it in assembler or C with a OOC programmer.

The sensor inputs and power control interfaces are where most people run into problems with projects like this.
It is one thing for it to work on the test bench with a nice clean supply, another thing entirely for it to work reliably amid the spikes and glitches that fill the real world.

If you wish to make things as painless as possible, then I would recommend a few things, most of which have been alluded to by the other contributors.

1. Choose someone to help you that can explain how and why in terms that make sense... If the explanation is overly ropey, you are probably on the wrong tram.

2. Clearly define the basic functionality and hardware etc and get that working before you try to "tart it up". The classic "mud map" is a great starting point. A golden rule of design is that things should be as simple as possible and no simpler...As soon as you get a complex solution to a problem working, a simpler solution becomes obvious.

3. I do not wish to advise counter to SA Born, but unless you absolutely know that the final device can be implemented using the entry-level PICs, use one of the higher spec devices, like a 28x2 or 40x2. They will have space for more lines of code, more inputs and outputs etc and the extra features never go astray. The extra cost of the chips is insignificant.

You will also learn so much more that way. If you modularise the hardware by treating the PIC board as a black box, then it is easy to upgrade the functionality.. Hint, buy at least 2 PICs, if you are learning as you go, there may be a few bits that let the magic smoke out. Do not open the antistatic packaging until you know why it is there..

There are several ways you can implement the PIC hardware pcb, the cheapest will cost you only a few bucks and some time...you will learn the most from that..BTW can you solder and do you have a Multimeter? Unless you get adventurous, you won't need a CRO.

Download and install the latest version of the Picaxe Progedit and read the 3 PDF helpfiles: Progedit menu| Help| Picaxe manual 2 basic commands etc.
Don't be put off if you don't understand stuff... I have done a fair bit of training over the years and 90% of the problem is understanding the basic concept.. and you won't look back once you get started.

4. Make sure your mentor has an understanding of system safety, this includes electrical safety and an awareness of what bad things can happen if 2 incompatible devices are active as a result of a hardware or software glitch. I nearly choke when I see some of the stuff that is put up on the web re audio amps etc...some of it is lethal if implemented as shown...Fail safe design is something you must get right first time..run everything past your mentor until you are sure why things happen.

BTW... 45 is definitely NOT old...
I have learned so much interesting stuff in the last 10 years, it may have something to do with me abandoning quite a few of my preconceptions.
You will see an increasing number of old buggers doing very interesting things.

Hope to hear back from you, I will try to remember and check this thread regularly.


Kind regards,

Glens.
I notice you only have a few posts. Are you still out there?
 

Ravenous

Member
I only recently started wearing shorts.

No really :)

My problem was I had a dad who wore safari suits and would say words like "cobber" when buying beer from a drive through.

It's taken a lot of therapy, but I can finally wear short pants.
I can joyfully put on a pair of short pants every day.

By Friday I can't squeeze any more on though! :eek:
 

CLUELESS1

Senior Member
Thread 38 pages long, is this a record? 378 Replies?

"so you can all expect lots of PICAXE converts just like me to appear soon"
 

120ThingsIn20Years

Senior Member
Some forums have an interesting way of looking at things. Often there is a thread that follows the progress or development of a person rather than a particular question.

The two are definitely not mutually exclusive.

As a result of trying to learn 120 things over the next 20 years, I've discovered that there is a lot of overlap as to what I'm trying to accomplish.

There's also a massive difference in how flexible the forums are in their ability to accommodate different approaches.

When I first joined this forum, I wouldn't even have considered that I might be able to contribute to the way it might accept or decline different types of threads. But after a lot of exploration of different models, I find myself genuinely impressed with the acceptance of this slightly different approach to hanging out on a forum.

The topic at hand here is my education, and the response has been nothing short of awesome.

I now know so much more than I could have ever hoped.

I push this PICAXE product, and this forum all over the place as a result of the amazing assistance I've received.

Members like SABorn went so far out of their way to help me and asked nothing in return.

You people truly have something worthwhile here on his forum. In my attempt to learn 120 new things in twenty years, I am exposed to a lot of forum communities and you guys rank right up there in the top few. Thank you from the bottom of my heart and the bottom of the the thousands that read but don't post. We really do appreciate all the information you give freely.

So keep up the good work all you amazing contributors.

Can you imagine how difficult all this stuff would be without the net, and forums like this?

As a result of this forum, I asked for an electronics section to be formed on another forum I frequent and there is now a thriving electronics section on backyard aquaponics with thousands of posts based around electronics and automation.

I find myself even contributing to the topic at hand. I recently spent a few hours on skype helping a young lass with code for her science project fish feeder. I actually contributed something instead of just asking and taking!

So in short,

Thanks people.

You have all been amazing.
 

120ThingsIn20Years

Senior Member
:)

Some things like learning how to make bread were pretty easy, but this electronics caper is life long me thinks

But it's amazing how much you can do with this picaxe stuff, even without a lot of electronics understanding. I still don't really understand the basics, but feel I can make pretty much whatever I can think I might want (because of all the support, not because I actually know stuff).

Recently my veggie garden has been getting attacked by birds, and I thought how easy it would be to use the sonic range finder things people use in robtics to detect an object within the field of view by setting a "looker" at a height just above my salad greens, and then hitting a relay to turn a servo to squirt some water over the garden freaking out the invading bird. (if this is an original idea I give it freely to the world to profit from as you see fit)

I'm not actually sure if I COULD do this with ease, but that doesn't matter at all.

My point is that I THINK I could do this with ease.

And THAT is awesome.

It means I'm willing to have a go at stuff that, only one day before I found this site, seemed like the stuff of science fiction.

Cracking effort people.

Thanks
 

120ThingsIn20Years

Senior Member
Thanks

I like the way you are thinking and asking the hard questions. I've had to think a bit about that last one!

Ok, voltage is pressure.

Current is flow rate in litres per second.

The velocity of the water doesn't really have an analogy for the resistor. So you put your finger over the pipe and the velocity goes up but that doesn't mean anything, what is important is that the flow rate goes down. The more you put your finger on the pipe, the higher a resistor you are creating, the less litres per second flow, right to the point where you have a very high resistance and there is no flow at all.

Also, while you might be squirting your hosepipe in the air, there is not really an 'outside world' like that in a circuit. Everything runs in a closed loop. The water starts at the top of the hill with a high voltage and no flow. You turn on a switch (open a valve at the top) and the water flows. It might flow through a resistor which could be a narrow pipe. (every wire is a resistor but usually a very low value one, like 0.01 ohms). Then your flow might go through a variable resistor, like a tap. Then it might go into something that does something useful, like a turbine (eg a motor). Then it ends up at the bottom of the hill. But you can't get rid of the water, and it still has to flow in a loop. Think of a battery as a self contained device that transports the water from the bottom back to the top of the hill.

Motors and lightbulbs are interesting because they change their resistance.

Turn on a lightbulb and it has a very low resistance so lots of current flows. As it heats up and emits light the resistance rises until a predetermined current flows.

Turn on a motor and it also has a very low resistance but this rises as the motor speeds up. This creates a back EMF, or voltage, that under no load conditions ends up being the same as the volts going in. Spin a 3V motor fast enough and it will generate 3V.

Oh, and two formulas already mentioned before.
V=IR where V is volts, I is current in amps, and R is resistance in ohms
W=IV where W is watts, I is current in amps and V is volts

Put 1V across a 1ohm resistor and 1 amp will flow.
How much heat will it produce?

1V x 1A = 1 watt.


Keep the questions coming!

Feel free to skip ahead to the important bit at the end*


I'm re-reading the thread to get my head back into gear before trying to make a few required devices for my epic 2000km Murray river solar powered boating adventure that I've been planing for around 50 of my 47 years.

Or at least it seems like that long.

But I did just take delivery of my solar panels, and acquire the office chair (from the side of the road) that when connected to the rudders will do the steering (I'll just think it, and will point in the required direction after a few days leaving my hands free to work the fly rod, and a laptop) so it must be about to happen soon :)

This week I found that one of the 10 batteries in my rechargeable vacuum had decided to be a little overwhelmed by the others and may have been doing the reverse polarity thing that it seems batteries can do. I swapped them with $21 worth of supermarket rechargeables, and now have a new lease of life on my $200 vacuum. In fact it lasts better than twice as long between charges.

I also have two of the same device (they have one upstairs and one downstairs) to repair for my mother in law with the same problem!

This Christmas is going to be sooooo easy :)

BTW for anyone interested, the device is a stand up vacuum with rotating head and LED headlights that has a small hand held device that clips into the body of the stand up device. The small device is like a dust buster (see back to the future).

They work really well, but the fault they develop turns the device off after a few seconds of operation. This seems to occur at around 2 to 4 years of use which is probably 500 charge cycles or so. I think this is the life span of NiMH batteries so I wont mention the brand as it's probably a reasonable run, and have nothing bad to say about them.

As I understand it, when you have a flaky battery amongst some good ones (I guess one has to be the first to fail) in series (ie + connected to - in a line) each additional battery adds it's voltage to the rest, and the result is that a failing battery can be coaxed into thinking that it's negative terminal should have a crack at being positive.

Or something. (I'm sure someone will correct me if I'm wrong)

Peer group pressure is much harder to resist when you are feeling tired it seems.

Anyway...

If you disconnect all the batteries (they are just AA NiMH) and check them, you will see they have a voltage of around 1.3v (mine were 1.34) but there was one that was only 1.28v.

Not a lot of difference, but it seems this was the culprit.

I'm sure I'll be corrected if I'm wrong about the reason, so check the date on this post before you pull apart your offending device and try to fix it. If this post is older than a week and I haven't been corrected, it's probably safe.

Anyway, the end result is...

1. a perfectly functional vacuum cleaner that lasts at least twice as long as it did when I bought it!

2. a decent way to make the mother in-law like me even more!

3. even more confidence in this electronics caper.

4. a renewed enthusiasm for making all the stuff I need for my boat (energy efficient lighting controls, water proof (epoxy set) LED tail lights for my boat trailer (so I dont have to sand down the contacts to the bulbs EVER SINGLE TIME I GO OUT), a device to keep both panels tracking the sun in (nearly) real time), a stack of other things, and a couple of ideas I want to take to market.



*So in short...

Thanks Dr_Acula, this is really good stuff..
 

120ThingsIn20Years

Senior Member
Hippy,

I like you explanation, im just glad you didnt use a ship for you battery, as then the men would have been called "sea men", now read your explantion with the term sea men in placement of men and it tells a completely different story.
Hippy's was a good description, and it helped a lot because I find a different analogy always sheds extra light. (Hippy 06-09-2011, 19:36 this thread)

But Pete, I cant believe you didn't mention inherent losses stuck between the sheets (of anode and cathode in the battery construction)*



*This is my fist attempt at an electronics joke, so cut me some slack people (I'm not even sure its a thing, but I have a vague feeling it might be slightly funny (I wont do(try (nested parenthesis)) it again)) :)
 

Ravenous

Member
If you disconnect all the batteries (they are just AA NiMH) and check them, you will see they have a voltage of around 1.3v (mine were 1.34) but there was one that was only 1.28v.
Is that in a fully (or nearly fully) charged condition? Those voltage readings don't sound bad on NiMH to me, though I'm not an expert either.

I think the real problem with one weak cell will be more obvious when they're nearly discharged, if one is at a really low voltage then, that one should be the problem cell. I tend to measure individual cells between 1.2-1.4 V in low current applications, and don't worry until I start to see one dropping to 1.1 or 1.0V. That's being really pedantic with a voltmeter though...

On the other hand if the vacuum really is cutting out with cell voltages around 1.2-1.3V, then I think the vacuum itself is cutting off too soon... (guess.)
 

geoff07

Senior Member
I suspect increased internal resistance may be part of the problem, as that won't show when measuring voltages off-load but will as soon as you turn on a heavy load. If you can do a load test on each cell you will soon see which ones to replace.
 

120ThingsIn20Years

Senior Member
The device works fine after replacing all the batteries, but I have a second one to repair.

How can I do a load test on an individual battery when it's within the line of series connect batteries? Or would I still have to de-solder each battery in turn and replace the connection with my multimeter?
 
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120ThingsIn20Years

Senior Member
I've started to build everything for my epic 2000 KM solar adventure on my little solar boat, and as I added the switch for my "SOS" strobe to the schematic, it got me thinking about how I might yell RF noise at the top of my boat's lungs in case of a snakebite or other impeding doom.

I realize most people try to cut things like this out of their circuits, but if I'm in real trouble (break glass to activate SOS) I want every farmer for miles to hear the SOS on their TV, radio, and UHF.

I read somewhere that a spark puts out noise on all frequencies. Is that true? I seem to remember being able to hear farm electric fences on my TV when the grass got too long and it rained. I presume that was because it was sparking to earth.

Would there be a better way to yell "SOS" on all (or lots of) frequencies other than making a big spark for each dot and dash?
 

inglewoodpete

Senior Member
How can I do a load test on an individual battery when it's within the line of series connect batteries? Or would I still have to de-solder each battery in turn and replace the connection with my multimeter?
The better quality rechargeable batteries, especially Lithium batteries, have charge monitoring/management for each cell.

(I know, I know: I'm not a South Australian. However, I am married to a South Australian born girl.)
 

premelec

Senior Member
@120 - you don't want to send SOS on lots of frequencies but on particular frequencies that the Coast Guard and other boats are using - concentrate your transmitting power where people are likely to be listening! Consult your local emergency services for what these frequencies are on your route-
 

120ThingsIn20Years

Senior Member
@120 - you don't want to send SOS on lots of frequencies but on particular frequencies that the Coast Guard and other boats are using - concentrate your transmitting power where people are likely to be listening! Consult your local emergency services for what these frequencies are on your route-
Thanks for the advice.

I'll be carrying a phone and UHF radio (Australian emergency UHF channels are 5 and 35), but there are a lot of cliffs on the River Murray and getting a signal out can be tricky at certain points along the river. I want something that screams a lot as a last ditch attempt to get help if I need it. I'll literally be putting the switch under glass to make it so it cant accidentally be set off (ie in case of emergency break glass).
 

premelec

Senior Member
@120T - a Very Pistol and box of noisy flares could be your answer - probably multi kilowatt noise generators will just annoy people as well as be hard to manage and for people to find the source... In times of monotony a few flares can amuse you - or set your boat alight by mistake :)
 

120ThingsIn20Years

Senior Member
@120T - a Very Pistol and box of noisy flares could be your answer - probably multi kilowatt noise generators will just annoy people as well as be hard to manage and for people to find the source... In times of monotony a few flares can amuse you - or set your boat alight by mistake :)
With tinder dry gum trees lining the banks I don't think I'll be letting off any flares :) (although I do carry orange smoke)

I'm getting the idea that nobody thinks this is a good idea, so I think I'll put it into the "Oh well" basket, and maybe look into air horns.
 

MPep

Senior Member
I've started to build everything for my epic 2000 KM solar adventure on my little solar boat, and as I added the switch for my "SOS" strobe to the schematic, it got me thinking about how I might yell RF noise at the top of my boat's lungs in case of a snakebite or other impeding doom.

I realize most people try to cut things like this out of their circuits, but if I'm in real trouble (break glass to activate SOS) I want every farmer for miles to hear the SOS on their TV, radio, and UHF.

I read somewhere that a spark puts out noise on all frequencies. Is that true? I seem to remember being able to hear farm electric fences on my TV when the grass got too long and it rained. I presume that was because it was sparking to earth.

Would there be a better way to yell "SOS" on all (or lots of) frequencies other than making a big spark for each dot and dash?
If you were to use a spark, then how would anybody decode it is you that is in trouble?
For marine situations, the use of Maritime VHF channel 16 is required to be used for emergencies, and an EPIRB (406MHz) is also HIGHLY recommended.
Now, I am uncertain of the situation in Australia, but I haven't heard of UHF channels being used for emergencies. In NZ, this is not recommended. Who would listen?
 

120ThingsIn20Years

Senior Member
If you were to use a spark, then how would anybody decode it is you that is in trouble?
For marine situations, the use of Maritime VHF channel 16 is required to be used for emergencies, and an EPIRB (406MHz) is also HIGHLY recommended.
Now, I am uncertain of the situation in Australia, but I haven't heard of UHF channels being used for emergencies. In NZ, this is not recommended. Who would listen?
When I get RF interference on my car radio, I don't think people everywhere get it. I think it's a reasonably local thing. I figured if it made someone turn on their UHF, or call the guy 50km down the river to see if they are hearing an SOS, then perhaps it might at least make someone look out the window to see my strobe :)

Lots of people listen to the emergency channels here. I think it's a volunteer thing, but I group scan the emergency channels, channel 11 (the channel you use when you want to contact someone, then move to another channel), the channel for whatever highway I'm on, and the channel I'm using if I'm travelling with someone in a different car. If you are scanning 4 or 5 channels, the group scan is so quick you don't miss anything when someone says something. By the time the person you are talking to actually starts speaking, your radio has paused on that channel. So you dont really notice that you are listening to the emergency channel as well as the one you are using. I think there's a law if you have a radio in a boat that it must be on.

I don't think you should be able to turn the emergency channel off. It should be fixed for every radio so that it scans if the radio is on.
 
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120ThingsIn20Years

Senior Member
Given this thread is all about my education, I guess this is as good a place as any for this question.

Is there a downside to reading variable values between different psudo Task threads?

I'm making a set of bike lights with indicators and have used "Main:" only for testing brake and indicator switches. a list of GOSUBs checks each switch in a loop, and when one is on, it sets a bit variable to 1.

Then Start1: loops through it's gosubs looking for say... the right indicator switch being 1.
It then calls the FlashLeft: gosub.

I do it with the various threads because I need to be able to set off the brake light when the indicator is looping through it's flashing sequence.

Is this how I'm meant to use these Tasks?

Is there a problem with doing it this way?

Is there a better way?

I suspect I'm doing something odd at least, because I rarely see the tasks: function being used (based on the samples of peoples programs I've looked at) and wonder why. Most of my little programs have used multitasking all through them.
 

120ThingsIn20Years

Senior Member
I'm not sure if this got answered along the way, but to answer this, a resistor is exactly like a tap. To continue the water analogy, voltage is pressure and current is flow. A resistor is a tap. A capacitor is a small tank on a hillside. (A battery is a very large tank on a hillside). An inductor is a long length of pipe, preferably made of steel because water hammer works better with a pipe that is not stretchy like plastic.

For a capacitor, the energy is stored as pressure. For an inductor the energy is stored as current, ie the flow.

If you turn on a tap connected to a long steel pipe then suddenly turn it off you get water hammer, which is a sudden rise in the voltage/pressure.

You can use this to change voltages and I mention this because this leads to a discussion of switch mode power supplies, and the advantage of a 'switcher' is you can convert your 12V from your battery to 5V with almost no energy loss. That means minimal heat loss, and this could be relevant if you are running lots of servos. For the moment though, stick with 7805 regulators.

I am really impressed that you asked the question about what a resistor is, and even thought of the tap analogy. That shows great insight into the way electronics works. Keep the questions coming!

James Moxham (2 years younger than you and living in the same state)
Thanks moxham. I dont think I thanked you for this information.
 

120ThingsIn20Years

Senior Member
We haven't even finished up with resistance, Pete. :)

The one difference in the water tap analogy that is important for resistors is that as current flows through them, voltage is dropped by them. As the "volume" of current flows through them, the "pressure" (voltage) drops. The difference between the input voltage and the output voltage means that there is a specific voltage difference between the input and the output that has been "dropped" by the resistor. Where did it go? It went into heat.

A resistor dissipates heat as it drops voltage, sometimes a little, sometimes a lot. The amount dissipated can be known by applying this formula: P=IR. That's Power (P) dissipated by the resistor equals current (I) times Resistance (R).

And no, I don't know why the letter "I" is used to represent current. Just a tradition, I guess. Perhaps someone else here knows. But by applying this formula you can calculate just how much heat will be dissipated (in Watts) by a given resistor at a given voltage or current.

That's important, because an incorrectly sized resistor can get too hot and start a fire, or pop like a fuse but in a much messier manner.

The other equation necessary for working with resistors is E=IR. That's E (for electromotive force {we call it voltage}) equals I (current) times R (resistance.) With this equation and knowing the values of any 2 of the variables you can calculate the third value. You will find many online calculators that will calculate these voltages, currents, resistances and power for you if you simply plug in the values you have. Just do a web search for "Ohm's Law calculator," or if you're handy with math just grab a pocket calculator and do it yourself.

Sorry if this sounds too inane. It's very difficult to know in the forum just what a poster already understands and what they don't, so I usually try to keep everything as simple as I can. It doesn't hurt those with a deeper knowledge, and it helps those who are looking at something totally foreign to them.
I think this is when I started getting sick, so depending on how I was feeling at the time, some of this stuff didnt stick.

Luckily/unfortunately, google never forgets.

It came up in a search for this very thing as I was looking into power saving adjustments to make projects last for as long as possible on a battery or two.

Thanks
 
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