Student project - documentation inconsistencies #1

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Paix

Senior Member
@Hippy,

For what it's worth, whilst browsing I noticed the following inconsistency:

Picaxe Home > Datasheets > Exemplar Student Projects
Fish Tank Heater

On the circuit diagram, the Picaxe 18 shows “in 1” from the Serial temperature firmware, and “out 1” to the green LED on leg 7 of the IC package.

No hint of the Serial temperature firmware seems to be available anywhere on the RevEd site. It does seem to be a bit of overkill, but not unreasonable. Did the Picaxe 18 not have a readtemp command?

In the program listing, the symbols “delay” and “counter” are redundant, not being subsequently referred to in the code.

I also notice that the +6V supply to the Picaxe chip appears to be at variance with the current Manual #1 recommendation on page 8 "Power Supply" not to use 6V, 7.2V or 9V battery packs, as these could permanently damage the chip.

Could this example perhaps be brought up to date with the 18M2 part in order to provide it's undoubted original intention of assisting young students?

I did surmise that the 08 or 08M part may have been the basis of the Serial temperature firmware, but that would have meant that the circuit was able to only read the DS18B20 One Wire Protocol chip on leg 2. I'm vaguely interested in the history of that bit of firmware if you remember it after ten years (eek!). The pdf is dated 2001.

I'm sure that you are grateful for me spotting this and that it will go into the black book of things to address, but I have to warn you that encouraging me is likely to be a frustrating pursuit as I will doubtless pour over some of the datasheets and after a while you will begin to lose patience with me. It's a bit like scorpions stinging, it's apparently just what they do . . .

Keep up the good work.
 
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westaust55

Moderator
The mentioned Serial temperature firmware is in fact the FRM030 which was releasein in 2002 when the PE was only at V2.3.7.
Datasheet: http://www.rev-ed.co.uk/docs/frm030.pdf

It was in fact the DS18S20 temp sensor via a PIC chip.

I would suggest that for all intents that the FRM030 is now obsolete as PICAXE chips have the READTEMP and READTEMP12 commands inbuilt now.


It has also been mentioned in the past that many of the datasheets indicated 6V for the PICAXE Vcc supply voltage level.

To "hi-jack" this thread slightly, Rev Ed may wish to also note that the PE revision list is well out of date at: http://www.rev-ed.co.uk/revision.txt
 
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Paix

Senior Member
Thanks for the historical update Westaust55. I did think that the firmware was due to lack of native support for the temperature device in use. I hadn't actually noted the older DS18S20 was in use - so that debunks the myth that I might make any sort of proof reader :) The DS18B20 offers an additional level of convenience to us today. I have two and suspect that I will be purchasing several more before very long.

We really are quite spoiled today and have a lot to be grateful for.

My dilemma, obviously, is that the line between useful feedback and harping on is both very fine and a bit variable.I know that I'm not too keen when I hear my XYL repeat yet again a failing that I am aware about, but is well under my daily interest and workload radar, somewhere just beyond the likely-events horizon.

I appreciate that keeping links solid over the site must be a significant job in itself, without constant review of the pdf content. itself; given the limit of available hours in the day and the multiplicity of other things to do.

Not hijacking the thread, but adding extra value and interest which is properly appreciated.
= = =
Hard to imagine that an 08M has sufficient capability to monitor and report back azimuth and elevation for an antenna setup as used by VK5ZAI; The simplicity and cost savings of using a Picaxe chip for the built-in ADC conversion is frankly quite astounding. I reckon Tony Hutchinson would have loved Picaxe and possibly does now.
 
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Xarren

Member
Paix - Just a suggestion, Maxim do samples on the DS18B20, just in case you don't feel like paying for them :).
 
P

Paix

Senior Member
@Xarren,
I have often seen the box inviting request for samples when browsing for a variety of chips, but have never chosen to ask, not knowing how I might qualify. Student, researcher, purchasing dept etc. I can see the logic. Get the developer out there familiar with your chips and they will become his standard component. It's a relatively cheap viral advertising campaign; as long as you are getting genuine users and not people just filling their bits boxes with components that might not get used.

We certainly live in electronically enlightened times.:)
 
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Xarren

Member
Maxim are very generous with the samples - as long as you have a business or educational email address (So not @gmail.com) they will be happy to send you samples. Generally in my experience, if you order about 40 components on sample, they will have a human review your order, if you pick 8 or so DS18B20s, you won't have the slighest problem, and they arrive pretty quickly as well.
 
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nick12ab

Senior Member
Xarren said:
Maxim are very generous with the samples - as long as you have a business or educational email address (So not @gmail.com) they will be happy to send you samples. Generally in my experience, if you order about 40 components on sample, they will have a human review your order, if you pick 8 or so DS18B20s, you won't have the slighest problem, and they arrive pretty quickly as well.
Click to expand...
So if I go with a large amount of components, I'll need an educational or business e-mail address but if i pick a small amount, does 'you won't have the slightest problem' only apply if i use an educational or business e-mail address or can I then use any e-mail address?

Is 8 a magic number for guaranteed getting-the-items or does that number vary depending on component prices?

Can Rev-Ed do sample PICAXEs?

Maybe Winstar will do sample OLEDs.
 
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Xarren

Member
You need a business/educational email address for any samples - And no 8 isn't a magic number, from my experience as long as you're not being excessive you won't have any problems getting the samples.
 
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