USB to ST4 guide output DIY or fully assembled and tested

Updated Aug 23, 2009

Updated firmware for better compatability with PHD on MAC

Updated July 13, 2009

Updated June 9, 2009

Updated June 4, 2009

Introduced May 15, 2009

All information required to build this is included on this page

Add an ST-4 output port to your computer for autoguiding your ST-4 capable telescope

Supported by ASCOM 'telescope' driver using 'PulseGuide'

PIC based (18F2550) for USB as CDC interface (USB-serial port)

Bootloader capable for upgrades in the field (SW2 controlled)

Max OSX Leopard support in PHD Guiding added 6/9/2009

Click here for PHD 1.10.5 OSX

Prototype project page, unit on a perf board

Use same ASCOM driver as the native USB-TTL serial 909 clone for guide control

See 909 clone page:

http://home.comcast.net/~lynol1000/as_909/as_909_clone.htm

See ASCOM guider software in action:

YouTube Video of Guide software

The video: “Enhanced 909 autoguider interface”

 

Click here for installation instructions on a PC
Click here for INF file for XP/Vista
Click here for ASCOM driver, full source included

Completed unit:

Circuit board dimensions: ( 1” x 3.7” , 25.4mm x 94mm)

Opto-isolated from scope. Two methods of isolation available:

Open collector pull to ground (Meade, Celestron, etc), good for 10ma @ 5V pull to 0.1V, Volts up to 15V

Open collector optoisolator specs

Optical Photo MOS FET Relays (almost any scope, any polarity using 6P6C connector), good for 100ma @ 5V pull in, Volts up to 30V

Optical relay specs

Shown with open collector chip PS2501-4 above center, optical relay right
Same socket accepts 2 TLP227A-2 photo mosfets for solid state relay at higher costs

 

USB B connector, units draws ~50ma via USB power

 

ST4 – ‘straight’ through 6P6C cable
Simple Windows INF file required for CDC class, uses windows USBSER driver, no other hardware drivers required

MAC supports CDC, no driver required to use with PHD Guiding

Click here for screen shot on MAC OSX showing device
Terminal screen is unit responding to ^F (0x6h) 'are you there' command with an 'A'

 

USB VID: 04D8 PID: FFE5 (VID = Microchip, PID under sub license from Microchip to me)

 

Bootloader VID: 04D8 PID: 003C (VID = Microchip, PID = Microchip HID bootloader)

 

ROHS compliant (check parts lists with vendors specified)

Components rated to –40C

 

HEX files for bootloader, application(v2) and Windows INF file

Click hereto download –only- if you agree to:

1)      not re-distribute or host these files at any other location

2)      For private, non-commercial use only

 

See below for bootloader

Availability if you do not want to build one yourself

Orders placed between Aug 25 and Sept 7 inclusive will be filled between Sept 8 and Sept 14. If this is not acceptable to you,
please do not order!

Aug 20, 2009
I have enough material for 11 total units
I have 4 units assembled and tested, ready to ship in 3 business days
If the currently assembled units are sold, there is a 5 business day ship time for non-assembled units
These are custom built and tested for 4-8 hours each
If this is not acceptable to you, please do not buy

If more than available stock is ordered I will refund money immediately when oversold condition is recognized
( 24 hours max) and provide an expected availability date.

I will only ship to North and South America, Europe, Japan and and Australia.
If you are from Italy -contact me- first for shipping quote
Orders from a country I will not ship to will be promptly refunded and not fulfilled

 

Email me if interested: astrogene1000_stuff AT yahoo.com

 

 

Parts list:

RS = Radioshack, M = Mouser, J = Jameco, D = Digikey

 

PIC Development

The Microchip MCC18 compiler

Microchip MCC18 compiler

 

The full suite for USB dev is here:

Microchip USB page

 

USB framework and examples: MCHPFSUSB Framework v2.4

Base of project code: USB Device - CDC - Serial Emulator

 

I modeled after the "PICDEM™ FS-USB" eval board in the software, making changes to the I/O ports as dictated by my design.

 

Be advised: To recompile the bootloader firmware you -must- install the MCC18 compiler as 60 day eval to get optimizations or else the code does -not- fit in the boot section! (hence the need because IO port changes versus the PICDEM board).

 

HID Bootloader for Microchip

I used the “HID Bootloader - Firmware for PIC18 Non-J Devices” source model modified to match pins chosen for SW2

And the hidbootloader.exe from here:

http://www.schmalzhaus.com/UBW32/FW/HIDBoot/

 

The unit does actually scream along, with the various PLL's inside you can run a 4Mhz crystal and get 48mhz internal clock speed. I use a 20mhz because I find they start more reliably than the slower crystals.

Base schematic (matches PCB)

Cick here for PDF of schematic (Courtesy gdk, thanks gdk!)

 

Copyright GC @2009