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Roanoke Robotics & Makers Club of Southwest Virginia Message Board › need a programmer in it for the fun of the project

need a programmer in it for the fun of the project

A former member
Post #: 17
The HMC5883 is a compass, whereas you need an accelerometer and gyroscope. The MPU-6050 is an accelerometer/gyro combo. You can get accelerometer/gyro/compass combos (like the MPU-9150), but the compass doesn't really help with balancing unless you do the really fancy math that will combine the three types of sensor's data. You can probably use a compass for navigation, though.
Gary Y.
user 38202422
Roanoke, VA
Post #: 36
I used the HMC5883 in the antenna hat project, was pretty easy to patch in code using the wire library. The compass provides direction, the feedback is noisy & somewhat inaccurate. It also isnt compensated if it is not perfectly level.
I did get an ADXL 345 3 axis accelerometer to use for axis angle feedback , but unfortunately havent had time to integrate it into any project to be able to share the experience.
Austin D.
user 116643312
Roanoke, VA
Post #: 38
Tim said:"I would suggest getting an AMU6050 inertial measuring unit for this project. I just picked up a couple from Amazon for about $6 each plus shipping, but the shipping was more than the hardware. even with the shipping it was less expensive than the Sparkfun 6050 unit."

that was what i was looking for but did not find. That link i posted was the item google pulled up when i searched AMU 6050 inertial unit.
Gary Y.
user 38202422
Roanoke, VA
Post #: 37
Ah-ha, the PN is MPU 6050.
The MPU-6000/6050 devices combine a 3-axis gyroscope and a 3-axis accelerometer on the same silicon die together with an onboard Digital Motion Processor™ (DMP™) capable of processing complex 9-axis MotionFusion algorithms. The parts’ integrated 9-axis MotionFusion algorithms access external magnetometers or other sensors through an auxiliary master I²C bus, allowing the devices to gather a full set of sensor data without intervention from the system processor.

If you dont mind waiting 3-4 weeks to get it, you can get them on ebay for $3 with free shipping.
You wont get any technical support. They have warranty, is a pain, but at the cost can order extras throw out bad ones if you get them and still come out ahead. http://www.ebay.com/i...­
Tim B.
Tim_Brandsberg
Goode, VA
Post #: 16
I bought two of the units found at the following link:

http://www.amazon.com...­

I can send you my spare, and if you order some more you can return one of yours to me

I am working diligently to work out the sketch for the arduino to work with this IMU and a PID controller for balancing. I have found a long string of communications between someone with a user name of KAS on the Arduino forum under the heading of balancing robot for dummies. interestingly enough, I think he started out with just an accelerometer chip but then added a gyro chip and combined the two signals in the Arduino script to get input to the PID controlling portion of the sketch. The beauty of the 6050 is the chip combines (Motionfusion processing) the accelerometer and gyro data internally and then passes the fused data to the Arduino along the digital I2C serial port. That saves a lot of Arduino processing.

I have get his full sketch up and decide what I have to cut out to eliminate the motion fusion calculations.


Tim Brandsberg
Tim B.
Tim_Brandsberg
Goode, VA
Post #: 17
okso i got the zip and i extracted it into programfilesx86/arduino/libraries tne ran the ino and it has errors i cant et it to pass ive been working on it for 3 hours and it is very aggravating. Im willing to do work on it im willing to do what i need to but i need a step by step tutorial to follow. or i can drive to meet anyone willing to show me i will drive as far as harisonburg or blacksburg. depending on the direction just for some help.
To setup files for use as part of the library, saving them to the library folder is not enough. Then you have to open the Arduino IDE, click on sketch int the menu bar, then select import library, then select add library. find and open the library you want to use in the file explorer window that comes up. Then try it.

Don't let it get you down that things don't work out right the first time. I have been working with and programming computers for over 50 years and that library issue knocked me for a loop for a few days. I never expect computer programs to work or do just what I want them to do the first time out.

Hang in there,

Tim Brandsberg

Austin D.
user 116643312
Roanoke, VA
Post #: 39
it was liberary has too long a name error i got when i shortened it the program still acted like it wasnt there i get 56 errors in the console window
Austin D.
user 116643312
Roanoke, VA
Post #: 40
i reuploaded those pics go back to page 5 http://www.meetup.com...­
and 6 http://www.meetup.com...­ to view them
Austin D.
user 116643312
Roanoke, VA
Post #: 41
i think my vex micro controller is not responding. I have plugged in 2 separate vex receivers and used 2 separate vex transmitters. I have also used 2 different antennas and even gone tethered. The reason i believe it has gone awl is because when i have the sabertooth powered by 2 12v batteries and the large 12 v motors plugged into that with the 2 information cables plugged into the vex board and the sabertooth set to (on-off-on-on-on-off) it has always worked b4 so i thought maybe if unplug the vex board from the sabertooth and plug the vex wired directly to a standard 5v vex motor then it still doesnt work. so then i thought maybe when i soldered the power directlyto the board i checked the connections and they were fine no bridges. Next i pluged in a standard 7.2 v nimh battery and that didnt work either but it all worked b4 last week. That was b4 i rewired everything and the only other explanation was that i have the settings wrong on the sabertooth but ive always used the same video to do tank rc control. it got rained on but that was 1 day b4 2 meetings ago. any help would be greatly appreciated. With it working i can test the bot for stabilization. without it working i would like to know if i can borrow a spare unit or possibly you tell me a cheap receiver /transmitter kit i can get for less than 20 bucks.

this is the video i look off of

Austin D.
user 116643312
Roanoke, VA
Post #: 42
ok so i got my vex to work it was a bad tether which i used for the antenna too here's a video

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