Wireless & autopilot

[Kaptah]

I asked about the sensors in a thread below. I am also interested in any comments regarding wireless connectivity to an autopilot. It seems to me that a short range wireless datalink would be a quite nice addition. But what about a GSM/GPRS connection in addition to the wireless link? This would enable a true long-range autopilot. I would think that most people would still like to see in real time what the aircraft is doing, even if there is a bunch of programmed waypoints?

Usually portable GSM products use a Li-Ion/polymer battery. Perhaps in an R/C plane it is not wise to add another battery, but just to use an existing battery? However, then a regulator is needed to the circuit. What would be an acceptable input voltage range for the autopilot/GSM package? Is for example 6V...8V ok? I guess many electric planes use something like 9V...12V at least, so is the 6-8V region a bad restriction? The input voltage effects the regulator circuit configuration.

Thanks again.

[flatland2d]

I think any UAV would be wise to have some wireless connectivity with its autopilot. In case things go wrong, you need to have a way to "kill" the UAV instead of it flying till it runs out of battery/fuel or crashes.

GSM/GPRS would be really cool in my opinion. I am in a group designing and building a UAV and we have considered this as an option. However, we have decided to go with MaxStream long range modems instead. We really don't need to be flying our plane from another country and none of us are familiar with the protocals. A downside is that you can only fly where you get mobile service, and many UAV scenarios this is not the case.

I'm not really sure what you're asking about the autopilot voltage. If the plane runs on 12V, you should have no problem regulating that down to 5V if that is what your autpilot needs.

[vector_vortex]

I am looking at telemetery options at the moment, and although I am looking for a short range options I have found a lot of cheap GSM/GPRS radio modems these:
http://www.m2mconnectivity.com.au/servlet/Display?p=95
have a nice RS232 that you should be able to interface to nicely with almost any Microcontroller/Microprocessor. What are the output power of the maxstream modems. I am looking at building a 900Mhz 1Watt data link
have fun.
Joel

[JeffElecRC]

I think for GSM/GPRS you will need a Sim Card in each modem? So that means you'll be paying your cell service provider for two data plans? That could get VERY expensive...

As for making a 900mhz 1 watt datalink... why bother? It would be cheaper and better to get a commercially available modem from Maxstream or Aerocomm.

[workshop]

Kaptah,

If you only want to downlink serial data from your GPS receiver to enable a "moving map" feature on the ground, you could use the audio channel of your Video TX if you have one...

Jeff

[macboffin]

Kaptah,

If you only want to downlink serial data from your GPS receiver to enable a "moving map" feature on the ground, you could use the audio channel of your Video TX if you have one...

Jeff

I agree that, simplest way to go, have been there done that. K.I.S.S. principle. Of course you could always have an onboard camera focussed on the GPS and swich to that camera as needed for a quick up-date!
Budget size, budger size...........!

[marnixh]

I've been reading through the forums and am intrigued by the idea of sending GPS data as well as other info through the audio channel of an airborne downlink. This would save both power and money. Currently I have a USB GPS receiver and will be buying this downlink:
http://wirelessvideocameras.net/product/A1
Any help would be appreciated, thanks.
Marnix

[workshop]

I have a solution I'm about to start working on that involves two microcontrollers (ATMEL ATtiny2313) programmed to perform as FSK modems for a GPS Downlink. I have the chips, code and schematics. I just have to start putting it together.

My microcontroller experience ends with the BasicStamp so I'm going to start a new thread to get some help with the ATMEL chips. Once I have a working system, I can offer programmed chips or kits for the rest of us to try/use.

Jeff