Reggie

A very sad day indeed, he was a true giant in his field and an inspiration, RIP Sir Patrick.

Excellent Job Bruce, I'm surprised that you had to use a vice to remove the knob though, I now wonder if a little bit of heat might've done the trick and loosened the red stuff?

Those pictures look very much like a celestron 80ed R&P focuser, http://www.celestron.com/media/catalog/product/cache/2/image/9df78eab33525d08d6e5fb8d27136e95/5/2/52280_80edrefractor_large.jpg

In the centre of the focuser knob, you can just about make out some little celestron stickers , those stickers are on a round nub, which the focuser shaft screws into, check if you focuser has that nub, if so you can be fairly certain that it's a screw on and you probably just need to be a bit braver twisting it to free it, I remember mine was quite stiff, obviously holding one knob whilst turning the other one will help (just in case you're tempted to just rack the focuser in and use that to hold the shaft whilst you twist the knob).

If it's not screwed on or screw on, then it's push fit, which means that twisting it will not be an issue as it will still come free, mine is 2 different metals for the shaft and the knob, the knob is ali, the shaft looks chrome plated.

Hi Chris, those are the same pinout as the sparkfun microchip eeprom, I think they might be compatiblem not that it's an issue, I just happen to have 3 of the sparkfun eeproms sitting here

I only started using ubuntu as a cross-compiling development environment, it came supplied as a VM with everything necessary pre-installed, the whole toolchain, which was incredibly useful as this particular toolchain wasn't run of the mill.

I might take a look at mint though, sounds interesting, I used to mess around on gentoo, lovely OS but incredibly slow when you have to do a full update, processors have thankfully moved on since the single core days

I've got a turion x2 laptop that I will use for astro stuff, and I've got a donated dual core X2 machine that will probably end up as an astro machine too. There's also an unused dual-chip xeon server box in my cupboard but it's far too noisy for its own good not really suitable for our hobby, those fans just aren't conducive to concentrating.

I have a core i7 machine, 6GB of ram, about a TB of storage on this machine, never had an issue with resources, I give my VM a couple of GB of ram, 2-3 cores and forget that it's even there depending on what I'm doing. We're talking XP here though, so the resources it uses will be much less of an impact than say windows7 or vista, or probably even ubuntu as that has now turned into bloatware.

Personally I don't have the money at £100 a go to buy another PC for something like this, it's a bit excessive, all he wanted to do was program his cable using XP If you reallly need un-hogged resources, you could look at dual booting on your existing hdd, or get a spare smallish hdd (not 40/80gb, they're incredibly slow these days) and use that to dual boot from.

You're welcome Glad it worked, virtual box is fantastic software, some usb stuff can be buggy but in general it only needs to be recognised enough for virtual box to install it's usb proxy driver and then you should be able to access it from the guest os. that way you can keep your windows OS for messing around with day to day stuff and linux for all the stuff they don't really want you to do

it only uses the host usb as a proxy, so the drivers are still loaded in the guest OS. If I'm running Linux in a VM, it loads a virtual box usb driver for the device, then the guest OS loads it's own real driver.

setup XP on a VM, use virtualbox https://www.virtualbox.org/ that way you don't have to find anything and dont' have to disturb your existing OS, you can also run linux in it too

Looking at a pl2303 datasheet it's a 2wire serial eeprom that's needed, 24c02, according to their reference design on this page: Welcome to Prolific

(top link)

which you can apparently get from fairchild:

http://willem.engen.nl/projects/DC5xx/FM24C03U.pdf

or atmel:

http://www.atmel.com/dyn/resources/prod_documents/doc0180.pdf

or ST-micro

Available on all the majors (farnell etc.) and ebay and of course places like www.sparkfun.com

Modify PL2303 PID & VID - KlaasDC

might be useful?

which eeprom do they use chris? eeproms are pretty cheap and come in dip packages.

ebay has loads of ftdi items, cheapest 5v device:

FTDI Basic Breakout for LilyPad Fio/Pro | eBay

Bear in mind that it doesn't have the RTS pin broken out so this board is useful for EQMod but not useful for things like a webcam mod, for webcam mods i would suggest something like this:

FT232RL RS232 FTDI USB to UART Breadkout for breadboard | eBay

As it can be breadboarded or soldered directly into stripboard (maplins do stripboard desgined to drop dip packages into with a gap between each side of the chip). Either of those boards are useful if you want to drop a usb to serial device into your project. The first link also has a handy dandy 'bridge' on the back which is set so that the gpio are 5v, easy to cut the bridge and solder bridge to the 3.3v IO signalling on the pad next to the VCCIO pad.

I must say, without doubt tht FTDI chips rock, they are incredibly versatile, you can use them as programmers for AVR chips (arduino microcontrollers amongst the many other chips atmel do), you can read/write epprom chips (like the one in the spc900/880nc webcams) and communicate with spi/i2c devices, there's even a £20 board that can do jtag!!

you can get a barebones ftdi on an 28-ssop to 28pin dip adapter for about £7 on ebay, just got to add a couple of caps and resistor, failing that, the cheapest I have seen is about £3 but that's for an individual ftdi 232rl chip, you would of course have to make your own pcb to attach it to.

I'm ok personally, I've got the 5v ftdi cable, a 5v/3.3v sparkfun ftdi breakout board, a barebones ssop 28 breakout board with ft232rl chip on it (also 3.3v or 5v IO) and one of these DLP Design USB Product Page (it does jtag as well) and another 3x ft232rl ssop chips ready to go into projects

While we're on the question of pic usart, is it anything like avr usart where different clock speeds will give different error margins at different baud rates chris?

Thanks for clearing that up dave, I wasn't sure if it was a standard 3.3v with 5v tolerant inputs or whether you could actually change it to be 5v IO. It seems that you either get 3.3v or 2.5v, so I was completely wrong and should've known better than to assume that they might have similar features to an ftdi chip.

It's 3.3v with a 5v tolerant input for the RX pin from the original post. I haven't looked at the chip involved but I'm guessing that the chip takes 5v in from the usb, then has an onboard regulator for 3.3v, and the IO pins are configurable for 3.3v/5v depending on whether the vccio pin is tied to 3.3v or 5v, at least that's the way it works on an ftdi cable.

Nice find Dave, I was looking at some usb to serial boards on ebay (ego china ebay shop) for a similar purpose, yours are a bit cheaper than those

I'm sort of glad that someones doing it and I sincerely hope I'm wrong about China in general and times really are changing over there and that this might be a dawn of a new era.

or that you have to futz with things twice a year for the clocks going forwards/backwards.

I'd also like to add my sincere thanks to Steve and FLO for first rate service and delivery, another very happy customer.