Firefly Primer - Intro to GH/Firefly for Arduino, Pachube and more

by Jason Kelly Johnson

Jul 27, 2010

The new Firefly Primer has been added to http://www.grasshopper3d.com/profile/firefly. The Firefly Primer is a 35 page introduction to using GH/Firefly with Arduino, Pachube and beyond. It covers basic installation, tools, examples, tutorials, basic electronics with many helpful links to get users started. We will be introducing many more tools in the next few months to allow GH/Firefly to connect with a wide range of additional micro-controllers, peripherals, actuators, sensors, web resources and more. Firefly has been beta-tested by over 60 users (architects, engineers, artists) and has proved to be a stable and versatile tool. We look forward to hearing what you think as we continue to develop Firefly!

  • Andy Payne

    Hi Michael,
    I can probably put something together that would do this... but can you tell me a little more about how this component might work? What inputs would it need? Wouldn't you need to know the speed of the motor at a given PWM value in order to know how long to send the pulse (which would ultimately correspond to the degree of rotation)? Let me know some of your thoughts on this, and I'll take a crack at it.

    Jul 28, 2010

  • Andy Payne

    If I remember correctly... the big issue was changing the PWM value changed the speed of the motor (which would correspond to less revolutions). So, in order for a component to be able to pulse correctly, you would need to know the speed of the motor at a given PWM value (which could be difficult to determine). I also think that since you were using the "hacked" servo, that it would behave differently than other servos. Regardless, I think as long as you knew the speed that the motor was operating at a given PWM value, you should be able to control the degree of rotation given a specified "pulse". I'll give this some more thought and try to put something together in the next week or two. I believe this same issue would apply for stepper motors.

    Jul 28, 2010

  • Jason Kelly Johnson

    Hey guys - This is a cut and paste from a web post that worked for me in the past. It should be pretty simple to incorporate this. I can do some tests when I get back to SF. I will try it with both a hacked servo and commercial model. I can add the hack info into the next version of the Primer.

    he servo wants intervals of 20ms and pulse widths of 1.5ms if it's going to do nothing. Widths greater than 1.5ms turn the servo counterclockwise, widths lower than 1.5ms turn the servo clockwise. When the servo is receiving 1.5ms width pulses, it's possible to adjust the set point with a tiny Phillips screw driver.

    Jul 28, 2010