Hello,

Been reading lots on the forum, but prompted an idea....

I have just set up (and got working) Raspberry Pi Indi Service with VM Kstars/Ekos machine on Windows 10 Host.

One thing I been reading is the Mount connection USB-> RS232 -> Handcontroller -> Mount has some issues and lag and better to skip the handcontroller and go direct with a USB-tty ->Mount.

Now, here lies my question.. I've had an idea, but being a noob not sure if its a stupid one (as sure someone would of done this already, and can't see anything online)

Would it be possible to use the Raspberry Pi GPIO Serial port to connect directly to a RJ45 cable (i.e. skipping the need for USB-TTY FTDI chip)

So GPIO -> Mount would be the connection.

Could you simply tell the EQMOD to use the port, or would it need different driver etc. (now you know why im asking the question) its the software bit I dont have the skills for..

Feedback on my idea welcome, happy if someone can tell me can't be done. Will save me experimenting and endless googling.

You can make your own EQDirect cable or buy one assembled.

Hi,
just one thing : be careful that Raspberry's GPIO TTL level is 3.3V, while the mount is 5V.
i think you will need level converter between your pi and the mount
After that, you can can setup your connection to /dev/ttyAMA0
Gilles

As Gilles said you should be careful with 3.3v on the RPi and protect it against burn, at least the GPIO input (rx pin) on the RPi.

If you don't want to implement by hand, something like this: www.sparkfun.com/products/12009

Yes, you can do this. Just keep in mind the following:
1) you MUST use 3.3V to 5V level converter (see nmac post above)
2) connect raspberry pi gpio rx/tx throught level converter to proper pins of RS232 plug (as per EQDirect note by Jasem). Beware these are not standard RS232 pins!
3) disable your tty console in your /etc/inittab and /boot/cmdline.txt
4) use standard eqmod_telescope driver and configure your serial port to /dev/ttyAMA0 (as per gilles post)

I have used this configuration before I connected my GPS to RPi serial port. Now I use USB-RS232 FTDI converter instead.

Thanks to everyone for the feedback.

I did bit more research and due to the level shift requirements there is not much to gain from using the GPIO pins over a FTDI USB to Serial.

So using that now, made my own RJ45 cable and seems to be working, just need to tune the autoguiding settings as that doesnt seem to want to guide out of the box!