USB EQDir for under £4

[malc-c]

I have tried to make USB EQDIR, according to your post, and failed. The PCB is exactly as yours - PL2303HX Rev.A. I connect the wires exactly as you, but every time i connect my EQ5 Pro to the laptop (Win XP with the latest Prolific driver) a message is popup - "Port Not Available"!

Where did i got wrong?! Help please...

Have you read the full thread. There are suggestions on how to bring up the levels from 3.3v to 5v for detection

Also if you go into device manager - is the device installed properly (you may need to download the drivers from the web)

[Tharsis]

This is how the USB looks from inside, and how i connect the wires, assuming that the orange cable is RX, and the blue cable is TX. I have no idea what role is playing the white and the green cables, so i isolate them.

[Tharsis]

Yes, the device is installed correctly, it becomes visible on the device manager, every time i plug it into the laptop. I have the latest driver from Prolific.

And why do i need to rase the levels from 3,3 to 5V, when the PCB is working on 3,3V, with 5V tolerance?

[malc-c]

Firstly your PCB isn't the same as the original in the first post

So it will be difficult to identify the pads unless you have a look at the data sheet for the chip and trace the tracks from each pin for RX and TX.

Have a re-read of the thread - Chris who is one of the EQMod developers and thus very experienced with these mounts has already stated that the TTL logic levels have to be 5v otherwise the mount will not respond. This was the reasoning behind the use of the Transistor and resistors being added to raise the 3.3v TTL levels to 5v.

[malc-c]

If you really get stuck, just purchase the genuine article from FTDI - the TTL-232R-5V

http://www.ftdichip.com/Products/Cables/USBTTLSerial.htm

Cheapest found on the web is £9 http://www.tronisoft.com/prod.php?id=2472

Sometimes it's not worth buying the cheap stuff of fleabay

[Gina]

Agreed - especially when you're dealing with hundreds of pounds worth of equipment. That's why I decided to buy a pukka EQDIR box

[Tharsis]

OK, can any of you take screenshots from the toolbox of EQMOD, to see how the settings looks like?

[idbvideo]

OK, can any of you take screenshots from the toolbox of EQMOD, to see how the settings looks like?

It is possible that the pinout is the same - but you never know.

Check which comm port the adaptor is working on in device manager - comm/lpt ports and use that in EQMOD, Mine is on COM6 uses timeout 1000, retry 1, baud 9600

As for the 3.3v - 5v issue - It depends on the length of cable you are using. The longer the cable thr greater the voltage drop obviously. Some people have reported that the adaptor works OK with their mount at 3.3v and others report that theirs do not work. Also component tollerences within the mount play a part in what tollerance the mount can cope with on the signal.

Hope that helps

[Gina]

TTL logic levels of the past used 0-0.3v as logic 0 and 1.8-3.3v as logic 1. The mounts use the modern CMOS logic which uses basically 0v and 5v with the threshold around 2.5v (2v - 3v). So 3.3v is getting a bit close to the threshold and even with a short cable is iffy. You might get away with using a pull up resistor bu it's far better to use the correct standard and that's 5v for a logic 1. Running close to the limit is likely to cause all sorts of problems and could put extra strain on the mount. As I've said before, it's not worth saving a few pence and risking hundreds of pounds worth of mount.

[malc-c]

@Tharsis - Googling the chip I came across the following schematic for the PL-2303 HXD (the HXA is now end of life and no longer in production from the end of October 2012). The only way to really identify which pins are what on the board you have is to use the schematic and follow the traces to each pin

[mindburner]

hi all

I just ordered one of these

http://cgi.ebay.co.u...em=180999412857

integrated leads and was wondering how to connect it to the 9 pin D-sub plug for an NEQ6

it look like just a matter of connecting the Dsub plug

pin 9 to TX

pin 6 to RX

pins 5 & 4 to ground

pin 1, the + can be left off as it's not required

does that sound about right?

Edited October 20, 2012 by mindburner

[malc-c]

hi all

I just ordered one of these

http://cgi.ebay.co.u...em=180999412857

integrated leads and was wondering how to connect it to the 9 pin D-sub plug for an NEQ6

it look like just a matter of connecting the Dsub plug

pin 9 to TX

pin 6 to RX

pins 5 & 4 to ground

pin 1, the + can be left off as it's not required

does that sound about right?

From the EQMod web site

To create the EQDIRECT-USB all theat is needed is to connect a 9 way "D" type plug to the flying lead of the TTL232R. The connections are as follows:

Solder Pin 6 of the 9 way D-type Plug to the Orange wire (TXD).

Solder Pin 9 of the 9 way D-type Plug to the Yellow wire (RXD).

Solder Pins 4 & 5 of the 9 way D-type Plug to the Black wire (GND).

Hope that helps

[mindburner]

That's brilliant Malcolm, thanks for finding that

[malc-c]

Don't go by the colour of the wires... looking at the pictures of the e-bay unit it would be Green, white and black

[mindburner]

Don't go by the colour of the wires... looking at the pictures of the e-bay unit it would be Green, white and black

hi yes just noticed that as they have used the orange for 5v.

Hopefully the plug will arrive soon and I get soldering

Edited October 21, 2012 by mindburner

[kriss13]

Hi

After I read all the posts here (and some hundreds others I'm a bit confused about one thing.

1.

I believe this is the usb-serial conversion circuit.

Where is the EQDIR (the box with circuits) in this direct USB-Mount connection? ( I red a warning not to connect the mount directly to PC)

2.

As a side note...

I have this cable, but I'm confused about what cables/adapters I need to further connect to get to the RJ45 plug of the EQ5. (I don't want to use the hand controller)

PC => usb-serial convereter => ??? => RJ45 of the mount.

thank you

[daz]

Does anyone have an opto-isolated circuit for the FTDI cable?

There seem to be about a trillion different ICs out there and I don't know if I'd need extra components to make it work??

My FTDI lead works perfectly, but slightly nervous about a direct connection....

[daz]

Would something like this work?

http://proto-pic.co.uk/opto-isolator-breakout/

[12dstring]

You'll need two boards for complete isolation, as the communication to the mount is bidirectional and the two opto-isolators on the board share the same power supply so you can't use both. You'd also need a 5V regulator as the power coming from the mount is ~12V.

But otherwise there's nothing in the schematic to suggest it wouldn't work.

[ursamajorro]

Connect the two cables as follows:

Gnd-Gnd

Rx-Tx

Tx-Rx

Why they are reversed?

[slickfonzy]

Connect the two cables as follows:

Gnd-Gnd

Rx-Tx

Tx-Rx

Why they are reversed?

The data transmission (Tx) from the device at one end of the cable needs to go to the receiver (Rx) of the device at the other end of the cable.

[ursamajorro]

Thanks, I got it!

[DougAtDallington]

Hi,

Anyone know where to source a 'USB to UART (TTL) Cable module PL2303 Converter' or current equivalent? It's no longer available from EBay.

I'd like to try my hand at a DIY EQDIR for my EQ8 mount - assuming EQDIR is compatible with the EQ8.

Thanks in anticipation, hot soldering iron at the ready! :-)

[Kolloth]

I've had a quick scan of the thread and I didnt see this question asked/answered, so apologies if i missed it but;

Does anyone know if the signal to/from the mount is 12V or 5V.

I'm planning on making a EQ Bluetooth adapter from a HC-06 module i have lying around. I'm going to run a voltage reg off the 12v from the mount but i dont know if i need to level shift the tx/rx pins. My module is 5v tolerant on those pins or at least it seems to be since it works fine with my Arduinos.

If the mount is sending 12v out then i'd need to level shift it down, which is easy enough.

[Dave_D]

Hi,

Anyone know where to source a 'USB to UART (TTL) Cable module PL2303 Converter' or current equivalent? It's no longer available from EBay.

I'd like to try my hand at a DIY EQDIR for my EQ8 mount - assuming EQDIR is compatible with the EQ8.

Thanks in anticipation, hot soldering iron at the ready! :-)

there's this one http://www.ebay.co.uk/itm/2pcs-PL2303-PL2303HX-USB-to-TTL-RS232-USB-Serial-Cable-Connector-Adapter-/261110516124?hash=item3ccb66499c only thing to worry about is the listing says it's not compatible with windows 8. wonder if that rules out windows 10 as the free upgrade is out in a few days. I use XP but y'know, others might have trouble.