I’ve been researching various methods/products to deliver a PPM signal for a certain project im working on (http://fpvlab.com/forums/showthread.php?35491-DIY-hand-held-ground-station-help-needed-with-some-switches. and http://openrcforums.com/forum/viewtopic.php?f=45&t=6600&sid=2cfb1ce041115eda899aef60261e40c5)
Basically I want to build an all in one drone control station. I’ll use 6 pots (2 joysticks [x+y] + 2 sliders), and 10 switches/encoders for different mode selections and wot-not, and I will also likely have another 2 pots from a playstation thumbstick. There will be an ubuntu computer in the station as well, running the drone control software. The drone software will interface with a telemetry module, while I plan to have the pots/switches etc have there outputs eventually going through a seperate RC transmitter module. I want to keep these transmissions seperate to allow for a failure or redundency.
It will all be powered by it’s own NiMh battery, with the required stepped down voltages, so if I need to power the maestros with 5V, I can.
From all of my potentially 18 analog inputs, I will generate 8 PWM/servo signals, selectable/configured in the Ubuntu environment using the pololu software and scripts.
Im thinking I will need to use 3 Mini Maestro 12’s. 2 of them for the analog inputs and the last one to handle the PWM/servo signals. My input configuration requires 26 pins, where the maestros will have a total of 36 pins, so there will be room for expansion if/when required.
I want to be able to run the 3 Maestros independently from the Ubuntu computer, only using the computer to monitor, change and manipulate the settings as required. If the computer fails for what ever reason, I want to still have the Maestros working. The Maestros will be connected to the computer all the time and never disconnected.
The computer will be running the control software of a drone, and will have a touch screen interface, so I hope the provided software will work with touch controls. (for information, the computer i’ll likely be using is an Odroid U3, SBC)
Once I get this running nicely, I will look to develop some new software specifically for this application, to give better functions more suited to my purpose.
I know there is already lots of code in Arduino to do something like this, but it just doesn’t quite fit what im trying to do. Anyway, here are my questions:
[li]With my potentiometers and switches/encoders, will they all require an analog input each?
If yes, does my configuration of the 3 Maestro 12s sound OK?[/li]
[li]Then what method of daisy chaining would be suggested?[/li]
[li]If not, what configuration is suggested?[/li][/ol][/:m]
[li]How can I ensure the Maestros stay operational if the ubuntu computer fails. (keep in mind the Maestros will be connected to the computer all the time, likely by USB)[/li]
[li]Will the provided software work OK in a touch screen Ubuntu environment?[/li]
[li]When the product pages for the maestros says it can drive a servo, does that mean it’s outputting a PWM signal from each pin, in the same way and RC receiver is outputting a PWM signal from each pin?
If not, what’s the difference between the signal this is outputting versus the signal an RC receiver is outputting from its pins?
Then to convert from this Maestro servo pulse to an RC PWM, can I use this method http://www.bobblick.com/techref/projects/sv2pwm/sv2pwm.html?[/li]
[li]If not, can it be done?[/li]
[li]If yes, is there a better way?[/li][/ol][/:m]
[li]If yes, then why in the maestro documentation does it say that only one pin can output a PWM signal to drive an LED or motor or whatever?
Can I connect 8 of the PWM/servo pins a PWM to PPM converter (like this: https://store.3drobotics.com/products/ppm-encoder) to connect to a transmitter module?[/li][/ol][/:m][/list:o][/:m]
[li]Is there anything else I could look at as an “off the shelf item” that might be able produce some PWM or PPM signal?[/li][/list:o]
I know I’ve asked a lot of questions here, but I need to make sure the hardware will perform as I need before I purchase them. Im doing this as a hobby project, so I don’t have lots of funds to throw at it unfortunately.
I hope somebody has the answers I want, I will be very appreciative.