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So long, and thanks for all the algorithms...

Having repaired far too many electric fence energisers, assume NOTHING. They are 'potentially' (sorry) LETHAL. Much of the safety is the assumption that animal hair/fur will limit the current delivered. Be very careful. I might try using a small coil placed 'close' to the output wire to see if...

Mosfet is fitted as a LOW side device is it? Why not drive the buzzer directly from the PicAxe pin?

Are you certain it is a buzzer and not just a transducer in a housing? I've found that a 12V piezo buzzer will buzz very loudly being driven directly from a processor pin at 4.5V (ish). The buzzers are also polarity aware and don't buzz if fitted with incorrect polarity.

To my mind, the board described would seem to need constant refreshing in order to display multiple digits at once. Assuming this to be the case, it would surely defeat the point of having the 74HC595s at all, other than to reduce the pins needed to connect to the display(s). In order to have...

That won't work for my Class A valve (tube) amp. It is super heavy, but only 20W RMS. I've rarely found the need for higher powers than this.

I too have not had any problems with blown speakers due to failure of the output stages. After working with audio products for far too many years, I would find that failure of one output transistor is followed (within a few nano seconds) by failure of ALL output transistors - leading to failure...

Aaahh... I see what you're saying there. [At last] I was expecting an implied 'return' would happen after the 'low b.3' command. Which doesn't happen. Possibly I was sidetracked by the lack of the 'goto' before 'reset1'. I stand corrected.

main: inc b1 if b1 > 4 then reset1 on b1 goto btn0, btn1, btn2, btn3, btn4 I was reading this section, posted as the original? With the 'reset1' directly above the 'on' goto' code I would expect 'btn0' to be executed, but last as opposed to first.

In the original code, wouldn't btn0 be executed after btn4? b1 would initially be 0, incremented to 1, btn1 would be "branched" to, b1 incremented, then btn2, btn3, btn4. As b1 is next incremented it would be greater than 4 so reset to 0 and btn0 "branched" to. The sequence would then repeat...

I`ve driven the red versions of these displays from 5V using a single 47R resistor in the common (Anode in my case). I did drive them through 74HC595 shift registers as I had four displays and needed to free up some pins on the processor. Not sure even I would use *no* current limiting...

I "draw" them on the dimension layer in Eagle as a rectangle. For slots I have sometimes added them to the slots and milling layer(s). I might also write a note in text within the area I'm expecting to be cut out saying some thing like "This is a rectangular hole, 133mm x 35mm" just in case...

With regards to cutting openings for displays and buttons, I now have a few approaches. The first method is to draw any slots, holes or openings on the PCB layer and have the PCB house cut the slots for me. I've drawn the PCB for my Grid Frequency Meter and positioned the LCD on the 'inside' of...

The C language itself may not always be quicker. For the Arduino your typed instructions are compiled before being downloaded to the target processor. These compiled instructions run at the native speed of the processor. For PicAxe your typed instructions are downloaded to the target processor...

Great Cow Basic has a very similar syntax to PicAxe. It also has a 'Graphical' programming method which appears similar to Blockly - I've not used either but it looks like a flowchart type programming method. Yes GCB can use Assembler directly. It is the full fat assembler too, and both BASIC...

Personally, I'd use an optocoupler, the LED connected through suitable resistor (and possibly reverse protection diode) to the alternator, the 'transistor' connected to the PicAxe.

I used a very similar approach in my Grid Frequency Meter project, listed somewhere on this forum. I alternately read Voltage and frequency. For a close approximation it worked really well.

Taking the minimal component approach... A self oscillating piezo connected with the +ve to 5Vsb and the -ve to 5V would sound when the PC was off but plugged in. The drain from the "off" 5V likely to pass a mA or two, enough to sound the piezo.

Why not get a "Smart" power strip that turns off the power to all sockets when the "monitored" socket draws no current? My vote goes to the KB814.

I despise MpLabX. With a passion. Never got any single program to compile! That's how I got started with PicAxe, it works. Should add that I've usually managed to figure things out in GCB on the very, very rare occasions when it hasn't just worked.