Motor Focuser Computer Interface

[peter_4059 (Peter)]

Does anyone have a Shoestring FCUSB motor focuser interface?

I'm wondering if this device will provide finer control of the focuser position than the motor focuser hand controller. I'm using an Orion AccuFocus with a crayford focuser. The AccuFocus only has speed adjustment.

The software that comes with the FCUSB has adjustment of motor speed, pulse time and PWM frequency.

Peter

[g__day (Matthew)]

I can inform you it does for a Meade motor focuser - which has on its hand controller 4 speed settings and two directions - the pulse is for the duration of a button depress as best as I can determine.

With a Shoestring FCUSB - there are 16 speed and duration of pulse can be set alot finer - so for me its a great asset!

[peter_4059 (Peter)]

Thanks for the info. Do you know what voltage the Meade controller was designed to run on? The orion focuser uses a 9V battery and I'm wondering if using the USB 5V is going to make much of a difference.

I found a review of the orion unit on cloudy nights that says my motor only draws 40mA at full speed so I'm assuming this isn't going to put too much strain on the USB port.

Peter

[g__day (Matthew)]

The Meade likes double current that USB supplies - which is fine - the motors runs slower so tuning is even finer.

[Loupy31 (Peter)]

Hi,
OK, so lets get this right, A USB port supplies 5V at 500ma, so Are you saying your focuser requires 1amp to work properly?

Loupy31

[g__day (Matthew)]

Define properly? The manual for the Meade motor focuser and the JMI usb adapter simply state the motor will work at a slower rate on the reduce voltage / current supplied by USB.

It's not a high speed drill - so how fast do you want this thing to move? I generally use it on its slowest possible speed - and then rarely because carbon fibre OTAs seem to keep their focus remarkably constant.

I like the way this set up works very, very much.