Posted by Jordi Muñoz on November 8, 2009 at 5:00pm
The new and flat version is now available for pre-order for just $129, the estimated shipping date should be Tuesday and you can get it here. I also have big discounts for dealers and high quantity orders.
Why "+" in the name? Because it's an Inertial Measure Unit (sensors and hardware filter circuitry) plus an Arduino-compatible processor that can run our Attitude Heading Reference System (AHRS) code, based on Bill Premerlani's DCM algorithm. This hardware consists of a 3 axis accelerometer and three gyro sensors, dual power regulator (3.3v and 5v), GPS port, an Atmega328@16mhz and a lot of status LED's. It's the cheapest IMU-AHRS on the market!Note: this IMU is not designed to work with ArduPilot as is, and is not a replacement for ArduPilot's thermopile sensors. We may in the future release versions that do work with ArduPilot, but this version is designed as a stand-alone IMU/AHRS, for use with your own projects.Includes the pin headers and all the sensors needed, some assembly is required.Features:-Flat Desing.-Low cost.-3 Axis Accelerometer.-3 Axis Gyroscope-Arduino Compatible.-Source Code included and Open Source!-Power LED (Green).-Status LEDs (Red, Blue, Yellow).-1 SPI port.-1 I2C port (possible expansion shield with magnetometers).-Two PWM outputs (for servos).-GPS port (uBlox ready!).-Protection diode.-Serial port output with servo standard connector for easy interface with any device (Ground, 5V, TX-OUT).-Latest Firmware-Board-Schematics-XY gyro LPR530AL-Z gyro LY530ALH-XYZ 3g Accel. ADXL335
I was able to verify that the high pass filters are a problem for us and need to be removed. If you have good soldering skills and equipment you may be able to do this. Look at the board diagram and schematic and locate the parts making up the high pass filters. - replace the 3 4.7 uF capacitors with jumpers and remove the 3 1Mohm resistors.
I used to know analog circuitry theory and a bit of it came back to me while I slept last night. I had the same thought and planned to get out my magnifying glass and soldering iron this evening and see if I can modify one circuit to remove the high pass filter and see if that solves the problem. Thank you for your input. Nice to hear that is the right idea before hacking by board.
Doug, as I can see the problem could be the High Pass filter on the gyros. I think HP filtering is not good for us (DCM could not handle this), we only need low pass filtering. The good news is that it seems to be easy to remove them (remove the resistors and short the capacitors to bypass the HP filter)
JJ.
Hello all,
Tell me please, have this board some impemented memory for record of flying data?
And how to store and analyse a log file of a fly? Trasfer it to ground station only?
I didnt find any information about it in manual...
Forgot to mention, the horizontal scale on that graph is time with the units being the serial output rate which is nominally 10Hz, so you can see the decay lasts quite a few seconds.
I have the ArduIMU+ Flat board in my hands and there appears to be a big problem. I think it is in the hardware analog filtering of the gyro outputs, but someone better at hardware needs to see what is wrong and how to fix it.
The attached graph shows the gyro response to a rotation about the x axis. I took the unit and rotated it relatively swiftly through 90 degrees (without saturating the gyro) and then brought it to rest. The easiest place to see the mis-behaviour is on the right side of the graph. You can see that rather than returning to a zero rotation rate the (analog filtered) gyro output overshoots and then slowly decays back to zero. Of course this completely wacks out the DCM. It is more difficult to see what occurs when the board is in motion, and of course my rotation by hand does not produce a real step response.
Hopefully someone up to speed on analog filtering can take a look at this result and the schematic and give some input on what is going on. I don't see a way to correct it in the software.
Edourad, I'm afraid that US regulations do not allow us to sell autopilots directly without going through some very tortured export approval processes. Trust me, the red tape we'd have to make you go through is a lot more painful than the extra shipping costs!
Comments
I was able to verify that the high pass filters are a problem for us and need to be removed. If you have good soldering skills and equipment you may be able to do this. Look at the board diagram and schematic and locate the parts making up the high pass filters. - replace the 3 4.7 uF capacitors with jumpers and remove the 3 1Mohm resistors.
I used to know analog circuitry theory and a bit of it came back to me while I slept last night. I had the same thought and planned to get out my magnifying glass and soldering iron this evening and see if I can modify one circuit to remove the high pass filter and see if that solves the problem. Thank you for your input. Nice to hear that is the right idea before hacking by board.
JJ.
Tell me please, have this board some impemented memory for record of flying data?
And how to store and analyse a log file of a fly? Trasfer it to ground station only?
I didnt find any information about it in manual...
I have the ArduIMU+ Flat board in my hands and there appears to be a big problem. I think it is in the hardware analog filtering of the gyro outputs, but someone better at hardware needs to see what is wrong and how to fix it.
The attached graph shows the gyro response to a rotation about the x axis. I took the unit and rotated it relatively swiftly through 90 degrees (without saturating the gyro) and then brought it to rest. The easiest place to see the mis-behaviour is on the right side of the graph. You can see that rather than returning to a zero rotation rate the (analog filtered) gyro output overshoots and then slowly decays back to zero. Of course this completely wacks out the DCM. It is more difficult to see what occurs when the board is in motion, and of course my rotation by hand does not produce a real step response.
Hopefully someone up to speed on analog filtering can take a look at this result and the schematic and give some input on what is going on. I don't see a way to correct it in the software.
=(
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