newbie question: pocket pc and GPS with contour mapping?

[RogerStenning]

OK, thanks. Mucho food for thought.

I think I need to find a shop in the London area, and have a play with a few, before deciding (not neccessarily that I'll buy at that point. I suspect - nay, I *know* - that better deals will be had on-line).

Any suggestions on shops to visit? FWIW, I'll be in the Bluewater area tommorrow, if that helps.

[RogerStenning]

OK, having considered all the options, I decided to go slow and easy. I got the iPaq h1940 (bluetooth enabled), and the Navman 4410 bluetooth GPS unit.

So far, so good (even if I can't get my damned PC to get hold of the latest service pack for SmartST). Doesn't get past the 'waiting for CD' bit. I think I know why that is. The CD drive isn't autorun-enabled. Anyhow, thanks for the advice and hints, folks: It's much appreciated.

Once I've had the above combo for a while, I'll upgrade to a more feature-packed iPaq, and probably the latest version of Fortuna clip-on GPS.

Next up: A windscreen mount for my iPaq, and a TRIPLE cigarette lighter splitter, for the GPS, iPaq, and my phone!

[Tim Buxton]

Roger,

I'm sure I've read somewhere that when you get the 'Waiting for CD' message, simply opening and closing the CD tray does the trick. Oh, and get a *quad* ciggie socket. You never know when that extra one might come in handy
_________________
Tim

[RogerStenning]

[DavidW]

Why not fit a circuit breaker?

I'm like you - I tend to over-engineer particularly protection. I'm an amateur too, by the way.



David

[RogerStenning]

David -

Good idea. I'll lok into that on Monday (day off). Can't be too expensive, and the added protection to the equipment, let alone the car, that it'd give, should make it worth the added expense.

Oh, and GM OM TNX FB de G1LIW ;)

(for the unititiated, that's Good Morning, Old Man, THanks(X), Fine Business - or "cheers for the info" )

[DavidW]

I'm thinking of putting a 24V to 12V convertor on to my power chair - primarily to allow me to pull power from the batteries to power a laptop when the chair is stationary.


Ideally I'd break in at the connector between the battery combiner loom and the power electronics, but the connectors appear to be proprietary to Penny and Giles Drive Technologies and don't appear to be readily available. The other way round is to connect to the charger socket on the controls, which is an XLR socket fused at somewhere around 12A.

Obviously I don't want to pull as much as 12A - I'd soon have flat batteries if I did that (the traction system has a couple of 12V 40Ah gel batteries giving a range of around 10 miles).


My intention is to put an Alfatronix 24V to 12V isolated convertor, rated at 12A continuous (which is overspecced significantly - the auto adapter for the laptop pulls a maximum of 8A at 12V and will normally pull rather less, especially if the DVD writer isn't used - when Dell ships the car adapter, I'll put it on my amateur radio power supply, which has a built in ammeter) on the top of the battery box using a big velcro strap. The power feed will be via a high quality Neutrik right angle XLR, and I intend to put a circuit breaker in the 24V side, probably at around 8A to allow for the specified 85% efficiency of the convertor.

The spec sheet on the Alfatronix unit is available here - the isolated convertor is protected against an internal fault causing 24V to appear across the 12V pins. It's not a cheap piece of kit, at around 100 pounds, but it's a lot cheaper than a destroyed laptop.


The batteries in most power chairs, including mine, have a breaker on top of them (at something like 35A in my chair - though I can't see the ratings), there'll be a fuse in the controller at something like 10A on the charging socket (which I don't want to blow - it's a pain to get it sorted).


Maplin AK12N looks quite good - an auto-resetting circuit breaker rated at 7A. As the FAQ talks about car bonnet, they sound just as happy at DC as at AC (they're rated to 250V AC). I could fairly cheaply stick one in the positive and one in the negative - as there's no earth as such on the chair, it seems wise to protect both rails.


I'm not sure what, if any, protection to put on the 12V side - considering that the convertor sounds to have some kind of fold-back protection and anything catastrophic should trip the breaker on the 24V side.

I may re-engineer one of those three or four way cigarette lighter sockets - primarily because Maplin only has line sockets, not chassis sockets, so a neat box is really out of the question (though the idea of several sockets, each with their own LED and circuit breaker on the positive pin does appeal).


Obviously heavy duty cable will be used. The Neutrik XLR right angle connector (NC3MRC) want round cable between 3.8 and 7.5mm outside diameter according to data sheet on the Farnell web site. The individual contacts can take up to 2.5mm2 cable for a rating of 16A according to the data sheet on the RS web site.

Maplin XS72P would work on the 24V side, which is a 15A rated 1.19mm2 cable - but isn't round. I could use 6A 2 core mains cable (Maplin CW69A), which is round and has a conductor cross-sectional area of 0.75mm2 (probably about a 10A rating at 24V). Farnell have a 10A version of that cable, which is probably ideal (conductor cross-sectional area of 1mm2 - it's 32/0.2 as opposed to 24/0.2) - but you have to buy 100m.

On the 12V side I'd probably replace whatever cable went to the socket block with better stuff - like Maplin XS72P. Maybe a 15A fuse or two (one in each line) is not a bad idea either - it's more a last resort sort of thing, but it may just protect against a strange fault in the convertor.


Comments, as always, are welcome.


73 OM ES GL = HPE CUAGN G1LIW DE G0WZA K

I am 12wpm Morse tested (in the days when you had to have a Morse certificate to operate on frequencies below 30MHz) and have some A1A operation on 3.5MHz logged. For those that don't know emission codes, A1A is hand keyed Morse.

Because Morse is relatively slow, things are abbreviated as much as possible - particularly for boilerplate stuff like greetings, departure, name, location and, of course as we're British, weather (WX GUD, for "the weather is good" would be appropriate today).


73 - best wishes

OM - old man (a term of endearment, actually - for ladies it's YL for young lady, for wife it's XYL - enough said...)

ES - and (it's very short in Morse dit di-di-dit)

GL - good luck

= is the break character (dah-di-di-di-dah), often used instead of the Morse full stop as it's shorter

HPE - hope (to)

CUAGN - see you again


The rest is pretty much required "on the air" by licence, certainly after any significant Morse 'over' when using a British licence. Giving Roger's callsign is optional but helps other people who may be listening, DE is from, the next few characters my callsign (which, amongst other things, tells you what class of licence I hold and some idea of when I may have first held that licence, as it's sufficiently old to be amongst those that were issued in strict alphabetical order).


K is "over - any station to reply". If I just wanted Roger to reply, I'd transmit KN (all run together - dah-di-dah-dah-dit), which is "over - the station I'm in contact with only to reply).

I pointedly did not include VA before the callsigns (again, all run together - di-di-di-dah-di-dah), which means "I have nothing more for you".


If anyone has ever listened to Amateur Radio (as anyone is allowed to do, whether or not they hold an Amateur licence) and heard any of these abbreviations being heard on phone (voice communications), particularly HI for laughter, that's just people being sad. You're supposed to talk in English, not radio-ese, and these abbreviations are only needed in low bandwidth data modes and Morse. However, they're sometimes used on the Internet for amusement's sake.



David

[RogerStenning]

David -

Damn, that's a *long* reply

OK, yeah, were I in your position, I doubt I'd want to mess with the chair PSU either. Sounds like a right royal pain in the rear (no pun intended) to get fixed if it goes fubar.

Regarding parts, etc:

The Alfatronix unit does sound a bit pricey, mate. Still, with the gear that you'll be looking to use, it may be a good protective investment.

I've also looked at the Maplin AK12N Auto-resetting circuit breaker. The bonus is that it should fit into a plastic enlosure easily enough. I'l be hading down to Maplin in either Croydon or Forest Hill on Monday, to (1) see if they've any in stock, and (2) actually get a grip on how large or small they are.

Regarding protection on the 12vDC side. I was considering twin-line blade fuses, probably at 15A QB. Since I have to use my existing lighter socket for my monile phone hands-free holder, the DC line would be right in from the battery, on a 30A twin cable (and the cable is still there, since I left the minicab industry a couple of years back to go on the busses instead). This may give me problems with the car battery, though, so I'll need to fit some form of voltage/current monitor into the adaptor box, I think.

Er... Maplin Do sell ligheter chassic socvkets, mate - look for WD68Y. Twin pole, rated to 16A.

Heh. I truly never could get to grips with morse. All power to your elbow for doing so - it's more'n I could ;)

And 73 2 u 2, OM!

ASIDE:

If there's anyone out there who's interested in UK Amateur Radio, btw, you could do a lot worse than look over at the Radio Society of Great Britain: http://www.rsgb.org/

On the GPS side, APRS (Automatic Position Reporting System) is being worked on by many Raio Amateurs, both here and in the USA. More on that is available here and here.[/url]

[DavidW]

You're quite right about the cigarette lighter sockets - though the Maplin ones are hideously expensive (7 pounds each!) and don't have a cover. Farnell have 658431 at £3.40 (plus VAT if I remember rightly).


I'll have to give this more thought. You're right about the price of the Alfatronix converter, but considering the cost of the power chair, the chair's batteries and the laptop, it's worth specifying something decent. The non-isolated one is about half the price.



David

[RogerStenning]

Hmm. I'd not looked at Farnell before now (I hate waiting for mail order. What can I say?!), but at that price, it looks good - and the cover is a nice touch, too!

Good God! Have you *looked* at the number of Circuit breakers they have?!

http://uk.farnell.com/jsp/search/searchresultstwo.jsp;jsessionid=FHGVJSNW3M5AFQFIAEXCFE4AVAAS2IV3?_dyncharset=ASCII&action=1&ImgDisp=Y&KWord=circuit+breaker&NPart=&MPart=&MName=&QText=&_DARGS=%2Fjsp%2Fsearch%2Fcontent%2Fadvancedproductsearchcontenttwo.jsp.1&x=0&y=0

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