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SPC900 LXmod yesyes style ;-)

yesyes

By yesyes
in DIY Astronomer

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JamesF

JamesF

Posted
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Dear me it's a long time since I made up serial cables. I have this phrase in my head that goes "two and three crossed, four and five crossed, six, eight and twenty looped back" which I think might be something to do with making a null modem cable, but that was twenty years ago.

Anyhow, I've written a program (on Linux) that tries to open the USB serial port. It "hangs" on open which I assume means that it isn't seeing either DCD or DSR. That in turn might mean it correctly handles the control pins and doesn't just spew stuff out on Tx "john thomas"-nilly.

James

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raiderturbo

raiderturbo

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Hi all again,

I have managed to complete the mod and housed it in a project box now, however I have a problem...

I have the settings setup correctly via SharpCap and the camera set to LX mode. The switch does seem to make a difference however it is like is is simply just giving the maximum exposure for whatever frames per second is selected and the exposure time slider seems to have no effect on the end result.

I've double, triple and quadruple checked everything and all connections seem to be ok. I have a multimeter, is there anything I should/could check? It's almost like the RTS output voltage is not changing as per exposure time settings...?

If you need more info, don't hesitate to ask...

Please help.

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raiderturbo

raiderturbo

Posted
Posted
Hi all again,

I have managed to complete the mod and housed it in a project box now, however I have a problem...

I have the settings setup correctly via SharpCap and the camera set to LX mode. The switch does seem to make a difference however it is like is is simply just giving the maximum exposure for whatever frames per second is selected and the exposure time slider seems to have no effect on the end result.

I've double, triple and quadruple checked everything and all connections seem to be ok. I have a multimeter, is there anything I should/could check? It's almost like the RTS output voltage is not changing as per exposure time settings...?

If you need more info, don't hesitate to ask...

Please help.

In addition to the above, please see the log file excerpt of the serial ports activity while using Sharpcap to perform a 40 second exposure:

(Please also note the 'SYS' or system timestamps)

<20120429203119.066 SYS>
Baud rate 9600
<20120429203119.066 SYS>
RTS off
<20120429203119.067 SYS>
Data bits=8, Stop bits=1, Parity=None
<20120429203119.066 SYS>
DTR on
<20120429203119.068 SYS>
Handflow: ControlHandShake=(DTR_CONTROL), FlowReplace=(), XonLimit=1024, XoffLimit=1024
<20120429203119.067 SYS>
Set chars: Eof=0x1A, Error=0x00, Break=0x00, Event=0x1A, Xon=0x11, Xoff=0x13
<20120429203119.385 SYS>
Baud rate 9600
<20120429203119.069 SYS>
RTS off
<20120429203119.385 SYS>
RTS off
<20120429203119.386 SYS>
Data bits=8, Stop bits=1, Parity=None
<20120429203119.385 SYS>
DTR off
<20120429203119.386 SYS>
Set chars: Eof=0x1A, Error=0x00, Break=0x00, Event=0x1A, Xon=0x11, Xoff=0x13
<20120429203119.387 SYS>
DTR off
<20120429203119.386 SYS>
Handflow: ControlHandShake=(), FlowReplace=(), XonLimit=1024, XoffLimit=1024
<20120429203119.438 SYS>
Baud rate 9600
<20120429203119.438 SYS>
DTR on
<20120429203119.438 SYS>
RTS off
<20120429203119.439 SYS>
Data bits=8, Stop bits=1, Parity=None
<20120429203119.439 SYS>
Set chars: Eof=0x1A, Error=0x00, Break=0x00, Event=0x1A, Xon=0x11, Xoff=0x13
<20120429203119.439 SYS>
Handflow: ControlHandShake=(DTR_CONTROL), FlowReplace=(), XonLimit=1024, XoffLimit=1024
<20120429203119.440 SYS>
DTR on
<20120429203119.490 SYS>
RTS on
<20120429203119.490 SYS>
Baud rate 9600
<20120429203119.491 SYS>
Data bits=8, Stop bits=1, Parity=None
<20120429203119.490 SYS>
DTR on
<20120429203119.491 SYS>
Set chars: Eof=0x1A, Error=0x00, Break=0x00, Event=0x1A, Xon=0x11, Xoff=0x13
<20120429203119.493 SYS>
RTS on
<20120429203119.492 SYS>
Handflow: ControlHandShake=(DTR_CONTROL), FlowReplace=(TRANSMIT_TOGGLE, RTS_CONTROL), XonLimit=1024, XoffLimit=1024
<20120429203159.194 SYS>
Baud rate 9600
<20120429203159.194 SYS>
DTR on
<20120429203159.194 SYS>
RTS off
<20120429203159.195 SYS>
Data bits=8, Stop bits=1, Parity=None
<20120429203159.195 SYS>
Set chars: Eof=0x1A, Error=0x00, Break=0x00, Event=0x1A, Xon=0x11, Xoff=0x13
<20120429203159.196 SYS>
Handflow: ControlHandShake=(DTR_CONTROL), FlowReplace=(), XonLimit=1024, XoffLimit=1024
<20120429203159.196 SYS>
RTS off
<20120429203159.482 SYS>
Baud rate 9600
<20120429203159.482 SYS>
DTR off
<20120429203159.482 SYS>
RTS off
<20120429203159.483 SYS>
Data bits=8, Stop bits=1, Parity=None
<20120429203159.483 SYS>
Handflow: ControlHandShake=(), FlowReplace=(), XonLimit=1024, XoffLimit=1024
<20120429203159.483 SYS>
Set chars: Eof=0x1A, Error=0x00, Break=0x00, Event=0x1A, Xon=0x11, Xoff=0x13
<20120429203159.484 SYS>
DTR off
<20120429203159.534 SYS>
RTS off
<20120429203159.534 SYS>
Baud rate 9600
<20120429203159.535 SYS>
Data bits=8, Stop bits=1, Parity=None
<20120429203159.534 SYS>
DTR on
<20120429203159.535 SYS>
Set chars: Eof=0x1A, Error=0x00, Break=0x00, Event=0x1A, Xon=0x11, Xoff=0x13
<20120429203159.536 SYS>
DTR on
<20120429203159.535 SYS>
Handflow: ControlHandShake=(DTR_CONTROL), FlowReplace=(), XonLimit=1024, XoffLimit=1024
<20120429203159.587 SYS>
RTS on
<20120429203159.586 SYS>
Baud rate 9600
<20120429203159.588 SYS>
Data bits=8, Stop bits=1, Parity=None
<20120429203159.588 SYS>
DTR on
<20120429203159.588 SYS>
Set chars: Eof=0x1A, Error=0x00, Break=0x00, Event=0x1A, Xon=0x11, Xoff=0x13
<20120429203159.590 SYS>
RTS on
<20120429203159.589 SYS>
Handflow: ControlHandShake=(DTR_CONTROL), FlowReplace=(TRANSMIT_TOGGLE, RTS_CONTROL), XonLimit=1024, XoffLimit=1024
<20120429203200.322 SYS>
DTR off
<20120429203200.322 SYS>
Purge the serial port: RXABORT, RXCLEAR
<20120429203200.322 SYS>
Purge the serial port: TXABORT, TXCLEAR
<20120429203200.338 SYS>
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JamesF

JamesF

Posted
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Nice. I have just popped open one of the USB hubs as used by Chris and all of the soldered connections have been liberally smeared in hot melt glue.

Unless there is a straightforward way to remove it cleanly I think I might have to cut off the USB sockets close to the ends and strip off the sheaths so I can leave the wires in situ and connect them to the camera/serial converter/fan. Fortunately I think I can re-use the input side as-is. It has a moulded on strain relief grommet that I can just cut a hole for in the lip of the new box.

James

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raiderturbo

raiderturbo

Posted
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Nice. I have just popped open one of the USB hubs as used by Chris and all of the soldered connections have been liberally smeared in hot melt glue.

Unless there is a straightforward way to remove it cleanly I think I might have to cut off the USB sockets close to the ends and strip off the sheaths so I can leave the wires in situ and connect them to the camera/serial converter/fan. Fortunately I think I can re-use the input side as-is. It has a moulded on strain relief grommet that I can just cut a hole for in the lip of the new box.

James

I had the same issue with my hub. Simply cut the glue with a sharp knife (carefully) and the glue should then pull off nice and easy... :(

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yesyes

yesyes

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Hi all,

I don't mean to bump but I've not yet had a reply. Can anyone help out with the above posts (#553 and #554)?

All help greatly appreciated! :(

Sorry, I missed your posts somehow...

Have you selected LX mode from the camera menu, not just changed the LX mode switch on the camera?

From the log I see that RTS was on for 40 seconds, so that should have been a 40 sec exposure. Can you measure the voltage on the RTS pin against GND during and before/after the exposure?

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JamesF

JamesF

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I had the same issue with my hub. Simply cut the glue with a sharp knife (carefully) and the glue should then pull off nice and easy... :(

Wahey! It does, too. Slipped the blade of my freshly-sharpened Opinel No. 8 into the glue flush with the circuit board and it peeled off easily. Lovely. I was expecting it to be far better bonded than that.

James

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raiderturbo

raiderturbo

Posted
Posted
Sorry, I missed your posts somehow...

Have you selected LX mode from the camera menu, not just changed the LX mode switch on the camera?

From the log I see that RTS was on for 40 seconds, so that should have been a 40 sec exposure. Can you measure the voltage on the RTS pin against GND during and before/after the exposure?

Thanks for getting back to me.

Yes, I did select the LX camera in Sharpcap.

I will test when I get back home later and let you know how I get on.

(I guessed also from the log that it appeared to be working but it's definately not...)

Fingers crossed it's something simple!

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raiderturbo

raiderturbo

Posted
Posted

Hi all,

I did some tests last night on the serial port RTS output and although my log files above suggest that the RTS is turning on/off, there is no change in the voltage on the RTS before/after/during exposure (the voltage remained still @ around 0.65v.

While I was there I tested the DTR, this was pulsing in time with the exposure time from 1.95v up to around 2.25v.

Any suggestions?

Thanks in advance!

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yesyes

yesyes

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Sounds like there's something wrong with that serial adapter you used. It should go to at least 5V when RTS or DTR are on.

Could you disconnect RTS and DTR from the LX circuit and test again? This should show if the adapter is faulty of your LX circuit is pulling down the levels.

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Kbramley

Kbramley

Posted
Posted

I have just done this mod myself and I am having similar problems to raiderturbo, I'm wondering if its because im using a

PL-2303HX chipset and not a PL-2303 chipset (when i ordered it the description said it was a PL-2303 grrrr). Im no expert in these things but did notice that the PL-2303HX datasheet mentions something about operating between 3.3V-2.5V (VDD_325 pin 4 on the chip), whereas the PL-2303 operates at 5V (VDD_232 pin 4 on the chip), also note the VDD subscripts are different (probably a clue here :hello2: )

Someone with a bit of electronics background make any sense of this?

Im thinking I may be going online to find another PL-2303 adapter shortly ( gotta desolder that darn D9 connector off again :) )

Cheers

Keith

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JamesF

JamesF

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Since my usb->serial adapter turned out not to be the one I thought it would be, I guess I should check it isn't the 3.3V version either. I'll do that later this evening, as my new soldering iron bits arrived today and I can (hopefully) finish off the mod, at least to the point of being able to test it before I box it up...

James

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yesyes

yesyes

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Although quite a lot of these adapters have level shifters between the PL2303 and the serial port side. So you would get around +-12V levels. Probably a good idea to measure the DTR and RTS levels on the individual adapters...

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JamesF

JamesF

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I have just done this mod myself and I am having similar problems to raiderturbo, I'm wondering if its because im using a

PL-2303HX chipset and not a PL-2303 chipset (when i ordered it the description said it was a PL-2303 grrrr).

If you follow Chris's link to his own site and look at the pictures there, you'll see that his USB<->serial converter is also the HX variant.

James

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JamesF

JamesF

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doh... i was just about to dig out one of these adapters to check whether it was HX. But checking the pictures is of course sooo much easier.. :hello2:

:)

I only happened to notice as I've been following your instructions whilst unsoldering the wires from mine.

For Keith's delight and delectation, it's on this page:

http://www.yesyes.info/index.php/how-tos/modding-an-spc880-900-webcam-for-long-exposure/

James

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