12 Jun
2006
12 Jun
'06
11:39 p.m.
Tony Duell wrote:
Maplin still exist, but they now sell mostly crap
consumer electronics.
There is a small selection of components in the catalogue, but very few
of them are kept in the shops. You have to special-order them. Yes we
have RS and Farnell, but they're effectively mail order only.
Not if you happen to live in Leeds. The trade counter's open to the public and
it's about ten minutes' walk from one of the stops on the main Armley Road bus
route. Order at the desk and wait 20-40 minutes (depending on order size) for
them to sort it, or ring ahead and it'll probably be ready by the time you get
down there.
All you really need is a Customer ID number - ring main sales and ask to
register for one. Simple as.
It's not a
problem to have to mail-order the main components for a project
(microcontrollers, memroy, power transformers, etc). It's a right pain
when you're half way through a design and find you've run out of 10k
resistors :-)
When I was over in the States a few years back (2001 I think), I picked up a
few packs of resistors from the 'bargain bin' at Radioshack. Yes they're
probably crap quality, but they work well enough for most things.
When I need a value I don't have, I usually order a strip of 50 or 100 of the
0.25W metal-film variant. ?1 +VAT for fifty resistors - certainly beats
Maplin's extortionate 70p for ten.
I've still yet to find a place that sells nickel shim stock though (I use it
for battery welding strips). I used to get it from McMaster-Carr, but they
won't do export orders any more.
I live in London. In the entire London area (which I
define as the bus
pass zone, and is a lot larger than most people think of as London), I
know of _one_ shop where I can pop in to get resistors, etc. To be fair
they have a good selection of common semiconductors too, but such places
are not at all common.
Around here there's Farnell and the local Maplin (spit). Apparently there's
also Bardwell's in Sheffield, but I don't know if they're still going.
Now what I would like to find is a decent supplier of electronics surplus.
Mainline were great up until their warehouse caught fire, Greenweld have
disappeared (good riddance, their Innovations-catalogue wares will not be
missed) and WCN don't seem to have much useful stock these days. Nor do they
seem to want to send me a copy of the current catalogue...
And magazines. 20 years ago there were many titles.
Now I can think of 2
(Elektor and Everyday/Practical Electronics).
EPE's a shadow of its former self. They won't take freelance submissions any
more, and 90% of their content is from Silicon Chip magazine. I fully intend
to let my subscription lapse when it's up for renewal.
Elektor is neat - their "no you can't have the firmware source" policy is a
bit crap though. They do publish more interesting stuff than EPE, and I find
myself spending longer reading an issue of Elektor than I do an issue of EPE
(I also tend to make a hell of a lot of scribbles in my 'neat circuit
snippets' notebook while I'm doing so).
Circuit Cellar is good too - kinda like an Americanised version of Elektor,
but with more "this is a cool trick" type articles -- the current issue has
the circuit diagram and firmware for a neat-looking motion-sensing glove based
on an AtMega MCU. They've had other stuff too (too much to list), and Jeff
Bachiochi's "From the Bench" column is usually worth reading.
One thing that's not helped are that ICs now come
in hacker-unfriendly
pacakges, and may require expensice programming software and hardware to
do anything with.
I've got a box full of homebrew adapter PCBs and turned-pin solder pins. When
I need to put a particularly fussy chip onto a breadboard, I make an adapter
in Autotrax and etch it. It takes longer, but it beats dead-bugging fine-pitch
chips.
On the software front, I just ignore anything that needs expensive software. I
once had the 'pleasure' of dealing with an FPGA vendor who was screaming about
how cheap their ICs were. I asked how much the development software was, and
got the answer "sorry, we can't tell you unless you sign an NDA." Sorry,
wrong
answer, you lose, thanks for playing.
There's a reason all the microcontrollers in my junkbox are Microchip PICs and
8051 derivatives (mostly Dallas Semiconductor "Speed It uP" series chips) -
free or cheap dev software. MPLAB is free, MetaLink Assembler is free too, and
the Dallas chips are programmed with a MAX232 and a toggle switch. All my
CPLDs are Xilinx - the Parallel Cable III schematic is open (it's an LS244
buffer and some passive termination circuitry) and ISE WebPack is free (but
bloody huge - about 200MB last time I checked, and the service packs are just
as big).
I can see why, I don't expect semiconductor
manufacturers to cater for a
very small market, but you know, it's a lot easier for the average home
constructor to hand-wire 100 TTL chips in DIL pacakges than to do battle
with a DGA packaed FPGA...
I don't really do wirewrap or Roadrunner wiring much these days. My last three
projects were built straight onto PCBs, then I patched the inevitable bugs
with copper tape and patch wires. If I find an unpatchable bug, I etch a new
PCB and move the old components onto the new board. Thankfully I haven't had
to do that yet...
At the moment I'm designing a 'proper' battery charger. Basically a
current-mode switchmode buck converter and a programmable current sink. I got
sick of the ?20 Chinese cheapshit chargers wrecking my expensive Sanyo NiMHs,
and dying after a year or two of fairly light use.
--
Phil. | Kitsune: Acorn RiscPC SA202 64M+6G ViewFinder
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