almost 12 years ago I am going to go ahead and start a topic here about IMU selection for the Segbot. It seems as though every time I find an IMU and write some code to make it work in the Segbot, the IMU is discontinued soon after. suggestions for new IMU's or comments on anyone else's experiences would be great.

almost 12 years ago Hi, I'm starting to build my segbot and I already have most of the components (motors, partial frame, Sabertooth 25 controller, Arduino Duemilanove). But since the recommended IMU's are mostly discontinued, I'm having to test out a number of different ones that I have, but with no success so far. These are the IMU's that I have tried: ADXL345 3-axis accelerometer MMA7631 3-axis accelerometer ADXL330 3-axis accelerometer MPU6050 3-axis accelerometer + 3-axis gyroscope I'd like to start out using the latest version of your code because it auto-calibrates the IMU's and has the option to start up in debugging mode. and I'm interested in using the MPU6050 because it is both an accelerometer and a gyro, but it seems this is a complicated IMU to configure, given that it requires its own I2C libraries. I might just get a new gyro to use with the MMA7631, but before I do. has there been any progress on finding replacement IMU's? FYI, I found that I had to delete the BYTE command from the code because it's not used in arduino 1.0.3: Serial.print(m1_speed, BYTE); Serial.print(m2_speed, BYTE); } Many thanks and looking forward to all replies!

almost 12 years ago Yes, when using Arduino IDE 1.0 and above, you have to change the serial commands from: Serial.print(m1_speed, BYTE); to: Serial.write(m1_speed); which writes to the serial port as a Byte. And I will be trying again to find a reliable source for a gyroscope... which I am thinking will be the one they sell at Radio Shack (Parallax 27911-RT), as it has been around for a while - even though it uses an I2c or SPI interface. I like analog sensors, but they are sadly being phased out.

over 11 years ago Thanks, I started a thread about that gyroscope as Sparkfun actually sells it: href="http://prototyperobotics.com/forums/forums/segbot/topics/lpy503al-gyroscope

over 11 years ago hi Im working on the imu code for a 6dof but im stuck , anybody success yet?

over 11 years ago

Hi Guys

 

I have some links for some gyros and accelerometers. could you please confir if i can use them for the Segbot !!

LPY550AL Dual-Axis (Pitch and Yaw or XZ) Gyro
http://www.ebay.com/itm/LPY550AL-Dual-Axis-Pitch-and-Yaw-or-XZ-Gyro-Perfect-With-Arduino-Uno-/190682508592?pt=LH_DefaultDomain_0&hash=item2c65902d30

with

Angle Sensor Inclination Accelerometer Acceleration Module
http://www.ebay.com/itm/ADXL335-3-axis-Analog-Output-Accelerometer-Module-angular-transducer-for-Arduino-/310508944191?pt=LH_DefaultDomain_0&hash=item484bc67b3f

For CODE V1

Or

LPY510AL Dual-Axis (Pitch and Yaw or XZ) Gyro
http://www.ebay.com/itm/LPY510AL-Dual-Axis-Pitch-and-Yaw-or-XZ-Gyro-Perfect-With-Arduino-Uno-/200765020183?pt=LH_DefaultDomain_0&hash=item2ebe871817

With

http://www.ebay.com/itm/MMA7361-Angle-Sensor-Inclination-Accelerometer-Acceleration-Module-For-Arduino-/251235735924?pt=LH_DefaultDomain_0&hash=item3a7ed11974

For CODE V2

Cheers

over 11 years ago

I searched around and found one left in stock from a supplier in Europe just last week. It is possible to still find one.

over 11 years ago

Hi there John,

Hope you're having a great day. I'm using your V3 Autocalibrate code and I understand I connect Digital Pin 1 of the Arduino to the Serial Input (S1) of the Sabertooth Motor Controller. I'm trying to understand each aspect of the code and I would like to know where exactly is this pin used in the code? Is it the  int engage_state = 1.  This is the only place I see 1 used in the code. I assume this is Digital Pin 1? If this is not Digital Pin 1 then which part of the code is using Digital Pin 1 to send a command to the Serial Input (S1) of the Sabertooth Motor Controller? Thank you in advance for you assistance.

over 11 years ago

Hi Jack,

Good question... this might seem a bit confusing, but the part that tells the Arduino to use pin D1 is actually the first line of the setup() function:

  // Start the Serial monitor at 9600bps
  Serial.begin(9600);

This is how you start the serial communication port on the Arduino, which by default uses digital pins 0 (rx) and 1 (tx). Since the serial communication pins cannot be changed, the Arduino just knows that anytime you do Serial.write() or Serial.print(), that you want to send serial data through the transmit pin (tx = D1). If you use the commands Serial.available() or Serial.read(), you are asking the Arduino to listen for serial data from another device on the receive pin (rx = D0). All serial data transfer will be done at the speed that is declared when you start the serial montior with Serial.begin(speed) command - so the other device (the one listening for or the one sending the data) must be set to operate at the same serial speed (measured in bits per second).

In our case, the Sabertooth can be set to a number of different speeds, but I typically use 9600bps for most scenarios. My bluetooth module from Sparkfun operates at 115200bps, which is quite a bit faster and allows for more data to be sent in the same amount of time - but this sketch is only writing serial data to the Sabertooth 20 times each second so we are fine with 9600. Here is the command we use in this sketch to actually send the serial data through pin D1:

  // Serial speed values write here:
  Serial.write(m1_speed);
  Serial.write(m2_speed);

The engage_state = 1, is a variable used to hold the value for whether or not the safety engage button is being pressed on the handlebar - pressing the button allows you to start riding.

 

over 11 years ago

Hi all...I'm new to the forum...based near Liverpool, UK.....and looking to build a one wheel version of the segbot...ie an electric unicycle!   I'm great with mechanics and engineering ( have my own home built CNC plasma cutter) and not too bad at electronics..but fall down on programming :-((

I have the new IMU 6050 6DOF board - very inexpensive on EBAY - and I have been trying, without sucess, to get the little teapot sketch to work as a basis to start in designing the unicycle electronics with help from the segbot code.  I'm wondering if my Arduino  duemilanova is compatible with this 6DOF board (I2C) or whether I need a later version?  I'd be grateful for any help on this as I think Digital IMU's are now the way to go and so inexpensive to buy.  So if anyone can point me to some example code that works with my Arduino.....cheers