DATV-Express Project

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G0EID
Posts: 22
Joined: Thu Oct 17, 2013 3:19 pm

Re: DATV-Express Project

Post by G0EID » Sun Jul 15, 2018 7:32 am

Hi Charles,
Thanks for the new release.
Please have a think about implementing GPIO pins on the Lime / Pluto boards,
same as you did on Express.
Maybe a switch on the output of the Lime board,
terminating the output during the Lime transceiver recalibration routine,
would be a simple solution to suppressing the unwanted spectrum produced?
If there is a way to test that calibration is complete,
maybe changes on the C/O pin could be delayed and used to signal that?
73
Dave

G4GUO
Posts: 626
Joined: Tue Feb 16, 2010 12:51 pm

Re: DATV-Express Project

Post by G4GUO » Sun Jul 15, 2018 7:40 am

Yes I had thought about that and it would be quite easy to do
but I was worried some people might damage their boards if they
1) couldn't solder the SMD GPIO pins to the board (it does not use a 2.54 mm pin spacing).
2) Didn't use the correct level converter for the interface.

FYI the GPIO pins are
Harwin part number M50-3600542 for the male
and M50-3100545 for it’s mate

They are available from Element14/Farnell
Nice little PCB project for someone would be a converter board
that plugs into the Lime.......

- Charles

G0EID
Posts: 22
Joined: Thu Oct 17, 2013 3:19 pm

Re: DATV-Express Project

Post by G0EID » Sun Jul 15, 2018 8:53 am

G4GUO wrote:
Sun Jul 15, 2018 7:40 am
Yes I had thought about that and it would be quite easy to do
but I was worried some people might damage their boards if they
1) couldn't solder the SMD GPIO pins to the board (it does not use a 2.54 mm pin spacing).
2) Didn't use the correct level converter for the interface.

FYI the GPIO pins are
Harwin part number M50-3600542 for the male
and M50-3100545 for it’s mate

They are available from Element14/Farnell
Nice little PCB project for someone would be a converter board
that plugs into the Lime.......

- Charles
Thanks for the P/N's, I'll add them to the next order and maybe look around for a cheap device programmer/adaptor with a 1.27mm pitch ribbon cable to fan-out.
I see there's a couple of GPIO's on J6, which is a 0.1" pitch header, along one edge of the Lime-Mini.
Maybe they could be used to repeat PTT and C/O for anyone unwilling to attempt soldering J5?
73
Dave

g0mjw
Posts: 888
Joined: Sat Sep 20, 2014 9:15 am

Re: DATV-Express Project

Post by g0mjw » Sun Jul 15, 2018 9:02 am

G4GUO wrote:
Sun Jul 15, 2018 7:40 am
Yes I had thought about that and it would be quite easy to do
but I was worried some people might damage their boards if they
1) couldn't solder the SMD GPIO pins to the board (it does not use a 2.54 mm pin spacing).
2) Didn't use the correct level converter for the interface.

FYI the GPIO pins are
Harwin part number M50-3600542 for the male
and M50-3100545 for it’s mate

They are available from Element14/Farnell
Nice little PCB project for someone would be a converter board
that plugs into the Lime.......

- Charles
Perhaps it might be easier if we were to agree on a standard interface based on USB IO? There are plenty of USB Relay modules on Ebay, choose one of those, use another of the FTDI boards we already use in Minitiouner, or the BV4626 or design our own? Then it wouldn't matter what SDR was in use as the IO is abstracted to another board.

Mike

G4GUO
Posts: 626
Joined: Tue Feb 16, 2010 12:51 pm

Re: DATV-Express Project

Post by G4GUO » Sun Jul 15, 2018 10:04 am

That is sort of what I am doing with my station upgrade but I am using Ethernet.
I was planning to use a protocol similar to the one for controlling rotators in GPredict but in
my case it is
SX\n X = ASCII 0 - 7, Select band, an 8 would be no bands selected
S?\n return which band is selected
T0\n receive
T1\n transmit
T?\n return transmit/receive state
It also has a manual override, so I can control it from Engineering rather than the Bridge.
I intend adding a hidden menu to the program available only to those
who know the secret word. I may also integrate the rotator control / QRA
calculator module I have into it. Then apart from raising and lowering the mast
I should be able to do everything remotely.

- Charles

G0EID
Posts: 22
Joined: Thu Oct 17, 2013 3:19 pm

Re: DATV-Express Project

Post by G0EID » Sun Jul 15, 2018 11:44 am

g0mjw wrote:
Sun Jul 15, 2018 9:02 am
G4GUO wrote:
Sun Jul 15, 2018 7:40 am
Yes I had thought about that and it would be quite easy to do
but I was worried some people might damage their boards if they
1) couldn't solder the SMD GPIO pins to the board (it does not use a 2.54 mm pin spacing).
2) Didn't use the correct level converter for the interface.

FYI the GPIO pins are
Harwin part number M50-3600542 for the male
and M50-3100545 for it’s mate

They are available from Element14/Farnell
Nice little PCB project for someone would be a converter board
that plugs into the Lime.......

- Charles
Perhaps it might be easier if we were to agree on a standard interface based on USB IO? There are plenty of USB Relay modules on Ebay, choose one of those, use another of the FTDI boards we already use in Minitiouner, or the BV4626 or design our own? Then it wouldn't matter what SDR was in use as the IO is abstracted to another board.

Mike
Good idea about the relay interface, fits in well with the hardware abstraction that Charles has already implemented in the Express Windows Transmitter to support Lime and Pluto boards.

I think the FTDI module would be the best choice, we at least know some of their foibles, like forgetting their configuration data once in a while, with that in mind, any commands sent to the relay interface would need to be wrapped around some robust error checking code, so we are confident that the rest of the system is ready, before sending RF.
Much better than asking OM to hunt around for a specific model of third party USB relay interface board.

If the Lime/Pluto hardware support makes it into the express_server on Linux, a standard USB gpio/relay interface might also be useful in the Portsdown project, where gpio pins are now at a premium, Portsdown could then continue to control the express_server, as it does now, offloading any hardware specific switching requirements for the new SDR boards?

73
Dave

G4GUO
Posts: 626
Joined: Tue Feb 16, 2010 12:51 pm

Re: DATV-Express Project

Post by G4GUO » Sun Jul 15, 2018 12:58 pm

The cheapest 2 channel USB controlled relay I could find on eBay was £3 from China. :o

g0mjw
Posts: 888
Joined: Sat Sep 20, 2014 9:15 am

Re: DATV-Express Project

Post by g0mjw » Sun Jul 15, 2018 1:33 pm

G4GUO wrote:
Sun Jul 15, 2018 12:58 pm
The cheapest 2 channel USB controlled relay I could find on eBay was £3 from China. :o
Yes - prices have risen since the pound fell, but still it's affordable.

G0EID
Posts: 22
Joined: Thu Oct 17, 2013 3:19 pm

Re: DATV-Express Project

Post by G0EID » Sun Jul 15, 2018 2:42 pm

g0mjw wrote:
Sun Jul 15, 2018 1:33 pm
G4GUO wrote:
Sun Jul 15, 2018 12:58 pm
The cheapest 2 channel USB controlled relay I could find on eBay was £3 from China. :o
Yes - prices have risen since the pound fell, but still it's affordable.
rr, finding a good supply of boards with documented USB interfaces, is the challenge.

How about an Arduino nano board, with a USB interface, talking HID?
Easily obtainable and stand a chance of working on Windows and Linux too?
With plenty of spare I/O pins, a microcontroller could provide feedback, something akin to the “Indicator” switches on traditional relays?

If anyone needs to switch high current loads then there's plenty of opto-isolated relay boards without USB interfaces that an Arduino could drive.
Dave

on4bhm
Posts: 79
Joined: Mon Oct 24, 2011 5:52 pm

Re: DATV-Express Project

Post by on4bhm » Mon Jul 30, 2018 4:34 pm

Hi,

I have a strange effect with the transmitter program.
i'm using a lime mini, but it was the same with my lime.

in SD and HD you get the effect of the picture getting unsharp, or a bit blocky
and after a few seconds the complete frame is sharp again.
this cycle goes on and on.


in HD i have to make a lot of changes (wave my arms for instance) to get the frame rebuild completely.

the video noise just seems to add up...until eveything is blurry.


what could be the reason for this.
have others have seen this behaviour?
using 25p9


73's on4bhm

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