Hey everybody,Do any of you have experience building an autopilot with a Gumstix module? I know the idea has been thrown around before, but I haven't seen much real discussion about it. I'm torn between the KISS philosophy and the idea of just having room to experiment (ie Arduino/ATMega vs. Gumstix).One intriguing use for a more robust processor is the ability to attach a USB webcam or special-purpose CCD camera. However, I know the limiting factor for beaming back to the ground is still radio speed. Also, there is the added complexity of setting up the Gumstix environment, plus the microcontroller probably needed to deal with analog signals.On the other hand, I would like to build a UAV platform for experimentation, ie attaching different sensors and modules and trying out different configurations. In this sense, it seems like using a Gumstix-level processor up-front would save me time and money later, since I would already know how to use it when I wanted to do more powerful things.Any advice/thoughts?
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Ive looked at the Gumstix Overo for an autonomous submarine, but it seems to be limited by its input pins only recieve a 10 bit resolution, which to me means i only have a 1 m resolution which is not quite good enough.
There wouldnt be a to upgrade the resolution of the pins or perhaps an external DAQ unit that could be integrated is there?
Something that popped up on my radar recently is http://www.xduino.com/ a full 32bit ARM Cortex 3 chip and a stack of rom/ram. The only thing it appears to really lack is a suitable number of PWM IO for driving servos/ecs/etc as it had 2 12-bit DACS. I it may be that the 48 pins of GPIO can be used as PWM but I cannot find any supporting evidence.
Xduino – ARM Compiler and IDE with Arduino-like support
ARM compiler with Arduino-like support for ARM Cortex-M3
Though I am new to DIY Drones, I'll take the plunge and disagree with some previous comments regarding ROI on a Gumstix based auto-pilot.
The Arduino platform is terrific, no doubt, but I'd say its best fit comes for sensor / pwm applications. For anything more advanced, they just don't pack enough crunching power. Neither do Netburner modules. Sure, they might suffice for simple GPS waypoint navigation, but not for computer vision guided UAVs.
Think of autonomous surveillance UAV capable of processing real-time video with GIS data, object localization and tracking or complex swarming modes to name a few. Even basic SW video stabilization requires a lot of processing power and for us mere mortals and hobbyist UAV aficionados, the Texas Instruments OMAP3 based SoCs such as the Gumstix Overo are one of the few viable and cost effective options out there. The best part is they come packed with a PowerVR SX530 GPU and beefy DSP letting us offload the video processing routines.
If you need them any smaller have a look at Logic's OMAP3 SoC. If you need any more, consider tiny Overo clusters. The tools are readily available both commercially and open source. There's a myriad of libraries and applications ready to run OOTB or with few modifications. No special programmers / interfaces required. You can easily test on a BeagleBoard if you prefer the ease of connectivity it offers and then deploy to and Overo later on.
IMO, those are all key points that differentiate the OMAP3 SoC such as the Gumstix from most other auto-pilot platforms. Sure, you pay a little more, but you receive A LOT more too! It boils down to what you wish to do with your UAV project. If it's to fly around autonomously, an Arduino or similar will do it justice and be cheap to boot too.
If you want your UAV to become a platform for performing interesting / useful autonomous tasks or do anything with RT video processing, the Gumstix Overo quickly becomes the most cost effective solution available today and I'd think it should suffice for many hobbyist UAVers for years to come.
Speaking of Gumstix based UAVs, head on to the PixHawk project for an extensively documented project!
as mentioned in the link above, I am engaged in developing an autopilot for fixed wing using the Gumstix. See http://www.voidpointer.de/easybot/index_en.html for example. So far, I am not disappointed to have choosen the Gumstix for main computer. Having a standardized software environment can enormously boost the development process. Gumstix in combination with Linux has the advantage to provide an uniform and convenient environment for rapid prototyping. Connecting a GPS is just a "cat /dev/ttyS3" and connecting I2C is easy as well. Using SD cards there is lots of disk space for extensive logging. I am currently testing the fusion of SRTM data with altitude information - SRTM files for Germany take about 200 MB - no problem for a Mini-SD. Bluetooth or Wi-Fi provide standardized communication. And even running at (only) 166 MHz my autopilot still has a big margin of computing power. With 4Hz GPS and 50Hz IMU rate "uptime" tells me a load average of 0.10. And I wouldn't say that $99 is expensive for a prototype.
About the fragile hirose connector: I had 3 severe crashes with the Easy Star the last years but the Gumstix and the connecting mother board are still working fine. The biggest disadvantage however is EMI. I am still struggling with shielding and opto couplers to get a "clean" EM environment.
When I started dealing with autopilots 5 years ago, I could hardly estimate how much computing power would be necessary for the task of sensor data fusion and navigation. Back then, the Gumstix was a good choice for me. Today I am looking for a even smaller 32-bit system mainly for space and EMI reasons.
They're not necessary anymore, too expensive, & too fragile thanks to those hirose connectors. Microprocessors are at the point they can do everything on 1 chip. Netburner can do a Linux environment for a lot less money.
Replies
Ive looked at the Gumstix Overo for an autonomous submarine, but it seems to be limited by its input pins only recieve a 10 bit resolution, which to me means i only have a 1 m resolution which is not quite good enough.
There wouldnt be a to upgrade the resolution of the pins or perhaps an external DAQ unit that could be integrated is there?
The Arduino platform is terrific, no doubt, but I'd say its best fit comes for sensor / pwm applications. For anything more advanced, they just don't pack enough crunching power. Neither do Netburner modules. Sure, they might suffice for simple GPS waypoint navigation, but not for computer vision guided UAVs.
Think of autonomous surveillance UAV capable of processing real-time video with GIS data, object localization and tracking or complex swarming modes to name a few. Even basic SW video stabilization requires a lot of processing power and for us mere mortals and hobbyist UAV aficionados, the Texas Instruments OMAP3 based SoCs such as the Gumstix Overo are one of the few viable and cost effective options out there. The best part is they come packed with a PowerVR SX530 GPU and beefy DSP letting us offload the video processing routines.
If you need them any smaller have a look at Logic's OMAP3 SoC. If you need any more, consider tiny Overo clusters. The tools are readily available both commercially and open source. There's a myriad of libraries and applications ready to run OOTB or with few modifications. No special programmers / interfaces required. You can easily test on a BeagleBoard if you prefer the ease of connectivity it offers and then deploy to and Overo later on.
IMO, those are all key points that differentiate the OMAP3 SoC such as the Gumstix from most other auto-pilot platforms. Sure, you pay a little more, but you receive A LOT more too! It boils down to what you wish to do with your UAV project. If it's to fly around autonomously, an Arduino or similar will do it justice and be cheap to boot too.
If you want your UAV to become a platform for performing interesting / useful autonomous tasks or do anything with RT video processing, the Gumstix Overo quickly becomes the most cost effective solution available today and I'd think it should suffice for many hobbyist UAVers for years to come.
Speaking of Gumstix based UAVs, head on to the PixHawk project for an extensively documented project!
Regards,
Karl
as mentioned in the link above, I am engaged in developing an autopilot for fixed wing using the Gumstix. See http://www.voidpointer.de/easybot/index_en.html for example. So far, I am not disappointed to have choosen the Gumstix for main computer. Having a standardized software environment can enormously boost the development process. Gumstix in combination with Linux has the advantage to provide an uniform and convenient environment for rapid prototyping. Connecting a GPS is just a "cat /dev/ttyS3" and connecting I2C is easy as well. Using SD cards there is lots of disk space for extensive logging. I am currently testing the fusion of SRTM data with altitude information - SRTM files for Germany take about 200 MB - no problem for a Mini-SD. Bluetooth or Wi-Fi provide standardized communication. And even running at (only) 166 MHz my autopilot still has a big margin of computing power. With 4Hz GPS and 50Hz IMU rate "uptime" tells me a load average of 0.10. And I wouldn't say that $99 is expensive for a prototype.
About the fragile hirose connector: I had 3 severe crashes with the Easy Star the last years but the Gumstix and the connecting mother board are still working fine. The biggest disadvantage however is EMI. I am still struggling with shielding and opto couplers to get a "clean" EM environment.
When I started dealing with autopilots 5 years ago, I could hardly estimate how much computing power would be necessary for the task of sensor data fusion and navigation. Back then, the Gumstix was a good choice for me. Today I am looking for a even smaller 32-bit system mainly for space and EMI reasons.
Regards, Achim.
Fixed wing
Heli
The general problem with them is that they're relatively expensive and need a lot of supporting parts to make an autopilot.