The Meade software protocol defines many of the commands needed to control a Meade LX-200 telescope. I incorporated almost all of them in HandyAvi (I am the author of HandyAvi.)

However, Meade did not include all of the commands that are available via their Hand-Control push buttons.

One of the missing functions is the set of controls that would be needed to invoke the Periodic Error Correction (PEC) Learn, Update, and Erase functions.

Now I am guessing that Meade thought that this would only be done by someone standing at the telescope operating the North, East, South, West direction controls to keep the guide star centered in a reticle box while looking at a star through an eyepiece with a reticle.

Since my telescope is remote, I would have to travel 250 miles there, hope for a "good seeing" night, and tune PEC while there.

BUT, you can tune the PEC by setting up autoguiding on a star and letting the autoguider make the corrections during a PEC training session. I've done it and it works fine if you have a night of good seeing conditions. The only problem is that I could not get into PEC training mode from 250 miles away.

I solved this problem by creating a hardware/software solution.

I had a spare Meade Hand Controller. I opened it and traced the pushbutton controls to their terminals. There are 19 pushbuttons that go to a terminal strip. I took some ribbon cable and soldered a wire to each of the pushbutton terminals. I then connected those wires via a connector to another connector that plugs into a usbi2cio board that provides up to 32 bits of user-configurable digital I/O. I only needed 19 of them of course. This board powers itself from the USB cable so it needs no external power supply.

Then I wrote software to control the usbi2cio board and made its layout look something like a Meade Hand Controller.

I mounted the usbi2cio board and the Meade Hand Controller on a piece of plywood that attaches to the pier of my remote telescope at Rancho Hidalgo. I also placed a video camera on the board so that I can use HandyAvi to see the display on the Meade Hand Controller so I can tell what state it is in.

So two usb ports are required, one for the usbi2cio board and one for the video camera.

usbi2cio board

usbi2cio board, Meade Hand Controller, and video camera

usbi2cio board, Meade Hand Controller, and video camera

usbi2cio board, Meade Hand Controller, and video camera. I can lift the hand controller out of the plywood board and use it as I normally would if I am at the site. That is why the long ribbon cable.

View of the camera output and the software keypad I created.


Another view of the camera output and the software keypad I created after pushing the Mode button.

So now, if seeing conditions are good, I can put the scope into the PEC training mode and train PEC remotely. I would of course be using the Maxim DL "Track" function to keep the star centered while PEC training is active. PEC can be trained and updated remotely as requred using this method...