120ThingsIn20Years
Senior Member
I don't really want to trademark it.
I was just kidding.
I was just kidding.
I had worked that out already - i just went along with the joke. Trademarking that would be like trademarking 'computer whizz' etc which wouldn't really be morally right.I don't really want to trademark it.
I was just kidding.
While you can certainly use quotes here as you already do, another option is to just address that person with @<members forum name>.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.
Hmmm, with respect to this thread, "120" has stated on the Backyard Aquaponic forum:If I have parsed the above correclty, this thread will be tangentialising onto fluid queries and wet plants - good luck team
yeah I covered thatThanks 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.
Oh great! I didn't even know I had to worry about counterfeit partsAlthough 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.
I notice you only have a few posts. Are you still out there?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 can joyfully put on a pair of short pants every day.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 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!
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)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.
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.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.
The better quality rechargeable batteries, especially Lithium batteries, have charge monitoring/management for each cell.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?
Thanks for the advice.@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-
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)@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
If you were to use a spark, then how would anybody decode it is you that is in trouble?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?
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 strobeIf 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?
Thanks moxham. I dont think I thanked you for this information.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)
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.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.