Basic electronics help

[Cornish JackParticipant @cornishjack]

G'day all. Some time back I asked for advice re. the above item as to use and experiment. One (at least) of our members recognised it and reckoned it was a useful bit of kit. Still waiting for the house/workshop rebuild to complete – probably not before early Summer and would like to find something to engage the few remaining brain cells in the meantime. Can anyone suggest an electronics primer which could be used to allow experimentation with this kit, please? I assume it requires basic digital/electronics learning and I start from a basis of knowing Ohms Law and otherwise zilch! Any pointers/suggestions welcome.

Rgds

Bill

[Cornish JackParticipant @cornishjack]

[MuzzerParticipant @muzzer]

It looks as if it dates from the (late) 80s and is obviously a teaching kit. The Intergoogle doesn't throw anything up under my control, so it's probably rather obscure.

The microprocessor is on the RH board, probably the bottom right of the large black ICs next to the crystal. You could get an idea of the date it was made if you look on the LH board which contains various input and output devices like a pot, motor, light sensor etc. The smaller ICs (8-16 pin) and metal cans there will mostly have 4 digit date codes eg "8834", which would indicate "1988 week 34" etc. Most of the date codes will probably fall within a year or so.

Given that this clearly didn't become well known or widely used, I doubt you will find any more info about it than you got with it – is there a manual? You will be limited to assember code, as the chances of running any form of compiler on an external machine are surely zero, even if you had the program (on cassette or giant floppy?). You'll need to know the instructions for the actual processor as well as the manual for the kit itself. If you are very lucky, skilful and persistent, you may be able to drive that motor and vary its speed using the pot. That will be quite a challenge!

Murray

[Michael GilliganParticipant @michaelgilligan61133]

It would be worth re-visiting the previous discussion.

MichaelG.

[Neil WyattModerator @neilwyatt]

Crikey, There's a post from me tracking down an (apparently) alive supplier!

Neil

[Neil WyattModerator @neilwyatt]

This might help you get started:

**LINK**

Let us know how you get on!

Neil

[Cornish JackParticipant @cornishjack]

Muzzer, and particularly Michael and Neil, thank you so much!

Quite amazing source of info. I should have gone back to the previous thread but I (wrongly) assumed that I had got as much as was available from that one and the original search came to an abrupt end in December with the house succumbing to the 'surge'

Given my electronic knowledge base, this will generate much head-banging but with the metal mangling toys still in limbo, I have no excuses for not getting down to it!! I realise that this stuff is 'old hat' for many of you but never having been exposed to it, my only efforts to apply it (monkey see, monkey do) speed controller from Jim Cox's book, resulted in a big bang and 'magic smoke' … "A little learning" etc.

Rgds

Bill

[MuzzerParticipant @muzzer]

Seems I was generous saying late 80s, by several years. Was available in several microprocessor flavours and this is the Z-80 version. Wow. And it's got the "Applications Board" too. What date is yours?

How utterly bizarre to find someone actually selling them. Well spotted Neil. They must have opened a time capsule containing an old shipment!

Good luck if you have a go!

Murray

[LADmachiningParticipant @ladmachining]

I seem to recall using this board (if not something very similar) when I was studying A level electronics in the mid-90's. Z80 processor if it is the one I am thinking of, although there could have been 6502 types as well.

Any programs we developed were written out in assembly language, then manually translated into machine code for entry into the keypad. Luckily the programs were never that big!

Nowadays, I would have said you would be better to get hold of an Arduino and use that to develop your programming and electronics skills.

Anthony

[Cornish JackParticipant @cornishjack]

Murray and Anthony, thank you. I am rapidly coming to the conclusion that this bit of kit is at least one step ahead of where I ought to be!! Having trawled for most of yesterday, everything I found assumed a greater knowledge (terminology/processes) than I have. My earlier plea for suggestions on primers for this area was, it seems, well founded! Will continue the search and put the MFP to one side for a while.

Rgds

Bill

[Roger HartParticipant @rogerhart88496]

Being a sad old Bas$%^d I still do programming and construction. My advice is to put this thing back in the loft, it will only confuse you. Much easier to start with an Arduino – it has current development tools and good basic (not BASIC) books and a good website and has modern cheap hardware. Start simple with a few examples and branch out from there.

[Russell EberhardtParticipant @russelleberhardt48058]

I would agree with Roger. The Arduino is good and well supported. Another one worth looking at is the Raspberry Pi which is usually programmed in Python rather than C.

Russell.

[Neil WyattModerator @neilwyatt]

It depends what Bill wants to achieve. If you have no end use in mind, and just want to learn a new skill and a bit about microprocessors, the effort will be rewarding.

It won't be wasted either as the general principles learned will apply to all microcontrollers/microprocessors – and will make any future projects with other platforms easier.

I'd also argue that knowing some machine code/assembly language really lets you understand how a computer works, and is more rewarding than wading in with python or C – if you want to learn those, why not just learn them on your PC?

Neil

[Cornish JackParticipant @cornishjack]

Roger, Russell, Neil thank you.

Points well taken and Neil has it right – no particular aim, just hoping to ingest enough learning to be able to read some of the posts on the forum, relating to this area, without thinking 'What on earth was that all about?' Hexadecimal, for instance, never featured anywhere in my working life and neither did integrated circuits etc – think MO/PA, valves and tuning coils and carbon pile regulators – the STR 18 was an ENORMOUS advance in comms technology for operators of that era!!! For this 79 year old, I think something like a 'John and Jane' book on electronics is needed!

Rgds

Bill

[Gordon WParticipant @gordonw]

I'm trying to do the same as C Jack, and have bought an arduino, a bag of assorted bits and a book. whole lot about £10. But my big problem is I still cannot understand half the language.

[Michael GilliganParticipant @michaelgilligan61133]

Popped into the public library this morning, and found this:

Arduino for Beginners – Essential Skills Every Maker Needs

Author: John Baitchtal

Publisher: Que ____ ISBN-13: 978-0-7897-4883-6

There's too much about 'construction' for it to be a bargain-buy for this community; but it looks worth a read … that's what libraries are for.

MichaelG.

[MuzzerParticipant @muzzer]

There are loads of good videos on Youtube if you search "arduino stepper", "raspberry pi stepper" or similar. To me, a good video is worth a couple of hours of reading. I tend to do both for best effect, as well as actually trying it out for real.

TBH, once you have lashed up a breadboard example to prove you can do it, you may as well move on to something more sophisticated such as one of these TinyG integrated processor / driver boards with associated G-code sender / GUI, which takes care of converting the code to stepper movement. There are loads of these machine controller boards out there now, based on Arduino-like processors, along with a variety of GUIs to control them. I can't imagine crafting one of these myself when you can pick them up at such a reasonable cost.

Here's a nice intro by someone who's not very technical but shows how straightforward it can be to get an Arduino stepper drive going. His other stuff is quite interesting too.

Murray

[martin perman 1Participant @martinperman1]

Gentlemen,

I have taken up an Arduino UNO R3 and bought a couple of books and bits and pieces and loving it, keeps my brain ticking over, I've been fault finding machine tools and Robots for most of my working life by tracing a fault to a board but this is the first time I've gone to board level and understanding how it works. As a mechanical engineer who has only had electrical training I use hydraulic/pneumatic terms to understand electronics i.e. resistor = flow restrictor, diode = one way valve, capacitor = storage vessel and so on, it works for me.

Martin P

[Michael GilliganParticipant @michaelgilligan61133]

Posted by Muzzer on 26/01/2015 18:00:57:

Here's a nice intro by someone who's not very technical but shows how straightforward it can be

.

Murray,

Could you fix the link please ?

Thanks

MichaelG.

[Neil WyattModerator @neilwyatt]

> resistor = flow restrictor, diode = one way valve, capacitor = storage vessel and so on, it works for me.

That's often how electronics is explained, which is why hardly any-one understands inductors

Neil

P.S. I suppose an inductor would be a very stretchy rubber tube. turn on the water and the flow increases as it stretches. Turn off the water and the flow fades down as the pipe returns to normal size.

[MuzzerParticipant @muzzer]

Michael – it was probably this. Finger trouble again!

Neil – inductance is rather like mass. Flow (current) doesn't like to be changed suddenly. You need a pressure difference (voltage) to speed up or slow down the flow rate. The longer the tube or the bigger the diameter, the greater the resulting mass / inertia.

Murray

[Anonymous]

In theory inductors are pretty straightforward. Both capacitors and inductors store energy; capacitors in an electric field and inductors in a magnetic field. Unlike ideal resistors both capacitors and inductors have time varying characteristics and the impedance is therefore frequency dependent.

What sorts the men from the boys is understanding the foibles of real world components. In general resistors are fairly benign, except at higher frequencies and/or high powers. Real capacitors are generally pretty good, but have a number of issues, often dependent upon the dielectric material; which is partly why there are a lot of them.

Understanding real inductors is what sorts the gurus from the men. Any real inductor is imperfect, and even calculating a value can be difficult. Air cored inductors are not too bad, but are limited to low values. Once core materials are introduced there are all sorts of imperfections. Core materials are often non-linear, have variable losses, and have finite limits. Over do the current and your inductor may suddenly cease behaving as one.

Andrew

[Martin KyteParticipant @martinkyte99762]

In Fact Andrew, energy considerations are a very good insight into circuit components. Some energy conversions are reversible and some are not. Friction is an example of non reversible process in which energy is lost as heat. Raising a Clock weight of winding up a spring are examples of reversible processes and energy can be recovered simply by reversing the process. Resistors dissipate electrical energy as heat, capacitors and inductors store or convert electrical energy to electric fields or magnetic fields. Both of these fields have some (resistance) to being changed which can be thought of in the same way as inertia.

regards Martin

[martin perman 1Participant @martinperman1]

Neil,

using your expanding bladder analogy and reading Andrews description can I see an inductor as a fixed pressure vessel put into water pipework to stop water hammer i.e. current is allowed to collect inside the inductor and then fed back into the supply under controlled conditions to stop overloading the circuit.

Martin P

[MuzzerParticipant @muzzer]

Not quite. You've got your caps and inductors confused. The water hammer effect is due to the inertia of the mass of moving water ie inductance. The bladder is like a capacitor and gives the water somewhere to go when the tap is suddenly turned off, without which a very high transient pressure could result.

Another solution for water hammer is a one way valve (flywheel diode) that allows the water to be bled off to a header tank (battery) or back to the reservoir.

[Author]

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