We have an application where we are currently using the Maestro tethered to a Windows host computer over a USB port and using Maestro Control Center to download scripts and run them as we need them. However, we are going to need a longer cable between the host computer and the Maestro than USB will permit.
So, I put an RS-232-to-TTL converter board on the Maestro and ran an RS-232 connection out to the host machine, Configured the Maestro so that it’s in UART mode with a fixed 9600 baud rate. If I bring up a terminal program, I can send high bit characters to the Maestro and it seems like something is there although I can’t see if what I am sending is valid or not.
BUT… when I bring Maestro Control Center up, it goes looking for the Maestro USB device and it does not allow me to tell it to talk to the Maestro over the serial port. Is there any way for me to do this or does this mean I’m going to have to ditch Maestro Control Center entirely? If it’s possible to talk over the serial port using the Linux version of the Control Center that would be fine as well.
I gather reading the forum that this isn’t a normal application and that most people are using the USB port for downloading configuration once and then letting the maestro run independently, but we have a wind tunnel test application where it must operate tethered.
The Maestro Control Center uses the Maestro’s native USB interface. You will need to extend your USB connection somehow if you want the Maestro Control Center to communicate with the Maestro. You might consider using RJ-45 to USB adapters to lengthen your USB connection.
Alternatively, you could use the Maestro’s serial interface and write your own software to send and receive bytes.
The Wixel does not have the ability to make a USB connection wireless, so you cannot use it to extend your USB connection to the Maestro. You can use a Wixel to make a wireless connection and send serial commands to the Maestro, but you would not be able to use the Maestro Control Center, since this would still not be using the native USB interface.
Thanks Brandon,
so is there a place for Wixels in wireless remote control of servos? can 2 or 3 potentiometers connect to a Maestro using serial protocol to control several servos? More generally, can you recomend Pololu components that i can use to wirelessly control servos?
thanks again,
vincent
Just to jump in real quick- you can control servos directly with the Wixel, but the library included in the SDK can only support six. Not sure how many you need. Note that there is no app for this, you would have to write your own. But it does work quite well. http://martinsant.net/?p=909
Martin
[quote]Just to jump in real quick- you can control servos directly with the Wixel, but the library included in the SDK can only support six. Not sure how many you need. Note that there is no app for this, you would have to write your own. But it does work quite well. martinsant.net/?p=909
Martin [/quote]
Martin, i appreciate your suggestion but i am intimidated by the idea of writing the whole app. i’m thinking 2 potentiometers for servo control and a button to trigger a camera on an Arduino with Wixel on Shield com communicating with another Wixel and Maestro. simple wireless control of a pan/tilt head with camera.
i’m only learning the programing and mechanics so i can get the pictures i want.
thanks,
vincent
The wireless serial app should work for that kind of application. The Wixel uses 3.3V logic, so you might consider connecting the Wixel to your Arduino via the Wixel Shield for Arduino, which has level shifting built into it.
When connecting the other Wixel to your Maestro, keep in mind that the Wixel’s inputs are not 5V-tolerant so you should not directly connect the Maestro’s TX line to the Wixel.
Brandon, thank you
i already purchased a Wixel Shield so i feel good about your suggestions.
one more, if i may,
i have a trigger cable for the camera that fires the camera when the two wires connect, usually by pressing a button that closes the circuit.
what ids the easiest way to connect the two wires to the Maestro so it will trigger the camera at each position?
then i can just start the script that is in the Maestro and let it shoot a 36 shot spherical pano.
much gratitude that such tools are available with such kind assistance.
vincent
You can probably accomplish this in several ways if you want to be creative, but a small relay might be the quickest and easiest way. I am not sure of the specifications of your camera system, but I expect the current draw is fairly small, so you might want a smaller relay than the ones we carry.
Alternatively, you might consider using a MOSFET connected directly to the Wixel.
There are USB Extender Cables (sometimes called repeaters) that you can get. The extender cable has a built-in USB amplifier that boosts the signal. I saw a 43ft USB Extender Cable on Amazon.
