Spring 2016 3DOT Goliath, Progression of Laser Tag components

April 8, 2016/in 3DoT Goliath, Communites, Goliath Generation #1, Members and Communities/by refaas0a

By: Kevin Moran (Electronics and Control Engineer)

In this post we will explore the progression in the components explored throughout this project to make the Laser Tag game possible.

My first idea was to use a laser diode as the emitter and a Photo-resistor as the receiver.
1. Pros:
  1. 15 meter range
  2. No Assembly required

Power dissipation of 75mW

Cons:
1. Dangerous to the human eye
2. No circuit to build and learn from

Simplistic Laser Receiver build with Fritzing diagrams (Photo-resistor)

Since we are designing a 3DoT Rover that will be manufactured for children, the laser was discarded. My next idea was to use a simple LED alongside a collimator to simulate a safer laser beam.
1. Pros:
  1. Safe to use
  2. 3 feet range

Power dissipation of 60mW

Cons:
1. Beam had a 3 inch diameter from 3 feet distance
2. Did not meet the “cool” requirement

Red LED with collimator powered by a 4.5V power supply and 220ohm resistor

The third option to be able to satisfy our requirements for the laser tag game was to use a Photo-transistor as a receiver alongside an IR LED as the emitter
1. Pros:
  1. Safe to use
  2. Will require PCB board to cancel our noise and filter signal

Analog voltage output can be manipulated

Cons:
1. Output contains noise.
2. Range has to be worked on

Not visible to naked eye

Although the range is not as impressive as the laser, this is a safe device to use, as Infrared Light is not absorbed by the human eye. By using this device I will be able to satisfy the rubric for the PCB schematic design, as I will be adding on a Schmitt Trigger, which will be discussed in the following blog post.

Emmiter/ Receiver

Voltage output using Arduino Analog Pins

This circuit still needs to be filtered out and passed through an Inverting Schmitt Trigger. The Schmitt trigger will filtered out the noise and using voltage resistors there will be two voltage thresholds. Which will then be digitized and sent to the microcontroller for processing.

Spring 2016 3DOT Goliath,Troubleshooting the 3Dot Board

April 8, 2016/in 3DoT Goliath, Communites, Goliath Generation #1/by refaas0a

By: Tae Min Lee (Systems)

After finishing the assembly of the 3Dot Board with our mentor Nick and Lawrence at AOSA we had to troubleshoot if we had any bad connections. These are some of the procedures Nick and the group came up with to test the 3Dot Boards by following the procedures shown below:

Test Procedure:

Take out the battery before testing using a multi meter
Set the multi meter to measure resistance setting in the 100k ohm range
1. Check for shorts on the Dual Motor Driver Chip
2. The measured impedance of any two pins should be much higher than the 100k ohm.
3. If a value of 0 resistance or close is displayed than you have a short
Check H-Bridges are bridged based on the schematic (figure 1)
1. Checked A01, A02, B02, B01
Upload a simple code to test the motors (figure 2)
1. Measured the voltage across the motor terminals to make sure the correct voltage was outputted

Conclusion:

No shorts were found on the 3Dot Board and the H-Bridge connections were connected. However, we encountered a problem when we tested the motor code only Motor A was operating at the time. Motor B on the other hand was not operating and the measured voltage across the motor B terminal was zero. We had Nick perform additional test on the 3Dot board and from his analysis the possible problems were either the Dual Motor Driver or the Atmel Chip being damaged during assembly or other causes (ex. shipment, electro static, heat, etc.).

References:

1- https://www.pololu.com/product/713

2-http://forum.arduino.cc/index.php?topic=214730.0

Spring 2016 3DOT Goliath, Uploading the Firmware onto the 3Dot Board

April 8, 2016/in 3DoT Goliath, Goliath Generation #1/by refaas0a

By: Tae Min Lee (Systems)

Before we upload any programs onto the PCB we have to upload a firmware. The ATMEL Mega32u4 we soldered on the 3Dot cannot function because the chip has not been programmed. In order to make the PCB programmable we will require to upload a firmware (programmable program) using ISP (In-System Programmer).

Steps we will be taking to uploading the firmware onto the PCB:

Install the USB driver for the AVRISP mkii (Guide: USB Driver Installation).
ISP connection pins are needed to communicate with a device through the SPI (Serial Peripheral Interface) using pins MOSI, MISO, Vcc, GND, SCK, RESET.
Using the ISP connector connect it to the ICSP header to reprogram the microprocessor.
1. When connecting the ISP connector onto the ICSP header make sure the orientation of the connection is correct. For more info refer to the AVRISP mkii Programming document.
Download the following zip file from https://github.com/sparkfun/Arduino_Boards
1. Extract Caterina-promicro8. hex file
  1. Open Arduino_Boards-master -> sparkfun -> avr -> bootloaders -> caterina
2. Open up AVR Studio 4 and click on AVR Icon shown below
3. Click on disconnected mode and go to Main tab and select the device that will be used and click read signature
4. Go to program tab and under flash open the file from step an and press program
Now you’re finished and ready to use the 3Dot Board

Sources:

https://github.com/sparkfun/Arduino_Boards

Spring 2016 3DOT Goliath, How to Create a Custom Command on the Arxterra Application

April 8, 2016/in 3DoT Goliath, Communites, Goliath Generation #1, Members and Communities/by refaas0a

By: Tae Min Lee (Mission, Systems, and Testing Engineer)

To create a custom command for your project on the Arxterra application we need to click on the gear icon and click on the “Custom Command and Telemetry Configuration” (shown below).

Now click on the “+” icon and a pop up menu will appear, now choose the type of command you want to interface. For our project we needed a simple on and off switch (Boolean)to turn on and turn off the laser shot (shown above).

Now we can customize our custom command by putting the label and the entry ID. The label will be the name of your custom command (ex. laser shot). For the entry ID we can choose a hexadecimal value (ranging from 0x40 to 0x5F) to assign our custom command. Once you finish the configuration of your custom command click “back” and click “done”. Now you will see your custom command displayed on your Arxterra Application.

Spring 2016 Pathfinder Solar Panels Implementation

April 4, 2016/in Pathfinder Generation #2, Pathfinder Legacy/by peiyuanxu93

By:

Tuong Vu (Sensors, Actuators and Power)

Table of Contents

Introduction:

Based on the requirements from the customer, the pathfinder must be able to self – charge its batteries using solar panels. This document explains the requirement for the solar panels and physical implementation based on batteries. The customer wants the pathfinder to be able to run for four hours and self-charge for eight hours. Our mission required the pathfinder to navigate around CSULB with the assistance of Google Tango Tablet.

Batteries:

The Batteries from older design are being used in order to power the motors system, pan and title system, and sensor system. These Batteries are Gens ace 7.4V 10000mAh Pd Based on the the test we conducted, these batteries are sufficient to support the pathfinder for the mission. The pathfinder draw an average of 1.43A while operating at full load in moving forward and backward, turning left and right, and stopping. Equation .1 shows the total time the pathfinder can operate with these batteries.

A DMM is measuring the average current drawn by the motors when the pathfinder is conducting a forwards, backwards, stop, and start maneuvers.

Calculation:

According to the batteries that we planning to use, the current supplied by the solar panels must be about 640 mA to charge our batteries from 0V, batteries are drained,to 7.4V. Fortunately, the batteries will never be totally drained to 0V, but our solar panel are adequate to charge the batteries from 1V to 3.2 V within 8 hours refer to equation 2 and equation 3.

Solar Panel:

Requirement:

12 Voltage

700 mAh

· ECO-WORTHY 10W Solar Panel 10 Watt 12 Volt PV Solar Module, Solar Cell Panel

· 22 Voltage output

· 450 mAh

2 X

· NPower Amorphous Solar Panel Battery Maintainer Kit – 2.5 Watts

· 2.5 Watt, 167 mAh maximum power output

· 22 V output

Pathfinder will utilize both two NPower Amorphous Solar Panel Battery and ECO-WORTHY 10W Solar Panel 10 Watt 12 Volt PV Solar Module as its charging mechanism, and the total current supply by the solar panels is about 640 mA ( max). Modifying the solar panels placement on the pathfinder to resemble the Arxterra logo; allow the pathfinder to be more efficient in obstacle avoidance.

Image.1 Arxterra Logo

( Solar Panel Configuration will closely resemble the Arxterra Logo to reduce collisions)

Source Materials:

https://www.batterystuff.com/kb/articles/solar-articles/solar-info.html ( Tutorial website for uderstanding the mechanic ofhow solar panels function )
http://www.amazon.com/ECO-WORTHY-Solar-Panel-Watt-Module/dp/B00OZC3X1C ( solar panel website for physical dimesions and electrical )
http://www.amazon.com/NPower-Amorphous-Solar-Battery-Maintainer/dp/B00A2OJ55U/ref=sr_1_1?s=lawn-garden&ie=UTF8&qid=1459759847&sr=1-1&keywords=NPower+Amorphous+Solar+Panel+Battery ( solar panel website for physical dimesions and electrical )
https://www.arxterra.com/ ( Solar panels implemenation.)

UFO Torque Test Spring 2016

April 4, 2016/in UFO, UFO Generation #6, Uncategorized/by Millenium_Falcon_Luis

Posted by: Luis Valdivia (Project Manager

By: Anthony Becerril (Systems Engineer)

Table of contents:

Test objective
Test Procedure and Criteria
- Preliminary work
- Procedure
Results
Conclusion
- Video
Appendix

Test Objective:

To create stable flight, the current quadcopter must not have yaw rotation being created by the Electric Ducted Fans (EDFs). This torque test will measure the necessary torque to counter the yaw rotation that exists. Theoretically, this torque will eliminate the yaw rotation and the counter torque will be produced via an additional fan to be implemented.

Test Procedure and Criteria:

Preliminary Work:

The torque seeked in this experiment will be calculated as follows:

Torque = F*r=F*(D/2)

r: radius; distance between center of rotation
D: diameter

F: force; force point

Figure 1.1 Representation of Torque setup:

Figure 1.2 Set up used on UFO quadcopter:

The setup built for this testing required the following:

A pulley system to support weight like that of a full water bottle
A lazy-susan-like platform for quadcopter to spin on
An adjustable weight to vary on pulley during testing (i.e. water bottle)
A latching system to prevent the quadcopter from flying

Procedure:

The procedure to execute this test is as follows:

Have fully charged battery ready [Appendix A]
Upload corresponding Arduino IDE code to Arduino Uno
Properly connect all necessary wires on quadcopter except for the battery [Appendix B]
Place the quadcopter onto the set up turntable. Make sure the hooks are properly attached
Have pulley weight properly attached to one of the EDFs
Have potentiometer set to max before plugging in battery
Plug in battery
Tune potentiometer to turn on angle. Wait for calibration as indicated by the beeping code [Appendix C]
Continue tuning potentiometer to higher thrust. Observe yaw rotation.
If rotation exists, add more water to bottle. Continue this step until no rotation
Take final weight and calculate final torque using the formula:

Torque=9.8ms2*radius *weight

Radius = 4.5” → 0.1143m

Weight= weight of object in Kg

Results:

Torques that were listed must have demonstrated rotation on the setup to be considered valid for our data collection.

Table 1.1 Data collected from eight tests:

Test #	mass(kg) of bottle after	throttle % from pot	Voltage (V) to the ESC	*Torque (kgfm)**
in class demo	0.0609	43.12%	2.16	0.068216526
1	0.018	25.90%	1.30	0.02016252
2	0.035	34.70%	1.74	0.0392049
3	0.04	40.33%	2.02	0.0448056
4	0.033	32.26%	1.61	0.03696462
5	0.042	39.10%	1.96	0.04704588
6	0.046	40.86%	2.04	0.05152644
7	0.076	44.77%	2.24	0.08513064

Figure 1.3 Plotted points torque v. voltage percentage from 5v to the ESC:

Figure 1.4 Plotted points torque v. voltage provided to the Electronic Speed Controllers:

Conclusion:

In conclusion we were able to gather multiple data points in our torque tests. Plotting our data points in excel, we can see the exponential trendline of the relation between torque of the quadcopter and voltage provided to the Electronic Speed Controller. These data points will help us understand how to maintain stability by producing our own counter torque. Using the 5th fan approach, we can determine what find to buy, based on necessary thrust to counter yaw torque.

Click here for a video of the torque set up in action!

Appendix:

A. Battery Charging Manual

B. Wiring Diagram for Torque Test

Figure 1.5 fritzing diagram for torque test electronics:

Figure 1.6 cable tree of electronics:

C. Electric Speed Controller beep code

Beep codes can be used for troubleshooting ESCs.

Spring 2016 Velociraptor: Center of Mass

April 3, 2016/in Velociraptor, Velociraptor Generation #1/by Khoivu0814

By: Mingyu Seo (M&D)

Introduction:

Humans use center of mass to balance, for example when we are standing on both feet our center of mass would be at the center of our body, but when we try to position or balance on one foot, we shift our body closer to the supporting leg which also shifts our center of mass to find balance. Our team has incorporated this idea to our robot in order to successfully perform both static and dynamic walking. Solidworks can calculate the center of mass and the total mass of our 3D model based on the design and dimension created by the Manufacturing & Design Engineer. Our level 1 requirement shows the robot should be able to complete the course using both static and dynamic walking. In order to successfully complete a static walk, the robot should be able to balance itself on one leg while the other leg takes a step forward. When we’re lifting one leg up it is very important for the center of mass to be as close to the most supported leg to maintain balance.

Method:

Solidworks can calculate the center of mass by simply changing the position of our robot. When we are performing a static walk, we will lift one leg up and use our head and tail as a counter mass to bring the center of mass closer to the supporting leg. The pictures shown below will explain how the center of mass shifts when the robot takes a step.

Figure 1: Standing on both feet

Figure 2: Lifting right leg

Figure 3: Lifting left leg

Figure 1. Shows, when the robot is standing on both feet, we could see that the center of mass (pink dot) is position right in between the two feet. Figure 2. Shows when we lift our right foot, we position our head and tail left in order to create a counterweight for our center of mass to be closer to the supporting leg (left leg). Lastly, Figure 3. Shows when the left foot is up, we would position our head and tail to swing right to move our center of mass closer to the right foot. Figure 2. & Figure 3. Shows that the center of mass hasn’t reached fully above the supporting leg, but this error was caused by the insufficient weight of the head and tail. Our design includes distributing our battery between the head and tail in order to minimize weight load on our body as well as create enough counter weight for our robot to perform static and dynamic walk. For 2016 Velociraptor team, Center of mass testing using Solidworks have helped to validate our Level 2 Requirement (#6) of maintaining balance while performing static walk.

Spring 2016 Velociraptor: Bluetooth & Arxterra

April 3, 2016/in Velociraptor, Velociraptor Generation #1/by Khoivu0814

By : Camilla Nelly Jensen (Systems Engineer)

In order to meet the project level 2 requirement 13 for the Velociraptor, the Bluetooth module shall be connected to the microcontroller to establish a wireless communication with the Arxterra application that is installed on an android device. Below are the instructions on how to establish this communication.

1.Download Arxterra application to Android device

Follow instruction from Getting Started: Arxterra Control Panel & Android Applications powerpoint on how to access to Arxterra Android Application and installing it to the android device.
Obtain permission to access the Arxterra Application from Mr. Jeff Gomes.

2. Build Bluetooth configuration on breadboard

According to the System Recourse Map, the HC-06 Bluetooth module is connected to the following pins on the Arduino microcontroller:
- HC-06 Ground (GND) pin to Arduino ground(GND).
- HC-06 power (Vcc) pin to Arduino 5 V – To power Bluetooth module.
- HC-06 TX/TXD pin to Arduino digital pin 0 (RX)- to transmit data from Arxterra app to MCU(Velociraptor).
- HC-06 RX/RXD pin to Arduino digital pin 1 (TX)- for Arxterra app to receive data from MCU(Velociraptor).
- The STATE and EN pins will not be used.

Figure 1:

Figure 1 displays the Bluetooth module that will be used to establish the wireless communication to the robot. On the Bluetooth module, the RXD and TXD pins are used for sending and receive data. The module operates at 3.6V to 5V. Receiving data via the RXD pin operate at 3.3V from Arduino.

Receiving data via the RXD line on the Bluetooth module from the Arduino can potentially burn the device. The Arduino transmits a higher voltage than the Bluetooth module can handle, therefore, modification needs to be done. The TX line of the Arduino transmits a voltage at 5V to the receiving pin RXD on the Bluetooth module, however, the RXD pin can only be operated at 3.3V. By implementing a voltage divider, this will drop the voltage to 3.3V coming into the RXD pin of the Bluetooth device and thus, protects it from being damaged.

Figure 2: Voltage Divider Equation – credit to 42 Bots

Figure 2 displays how the voltage divider is set up in order reduce the voltage from TX to the RXD pin of the Module.

The Bluetooth module uses 3 x 10k ohm resistors in series and the calculations are shown below in figure 3:

Figure 3: Voltage divider calculations for Velociraptor

3. Establish Bluetooth connection between Android device and Arduino

The Bluetooth schematic on the breadboard is shown in figure 4.

Figure 4: Bluetooth setup

The Bluetooth module uses the Arduino IDE code which has the latest version of the Arxrobot firmware. The codes can be downloaded from Github.
Under the Arxrobot_firmware tab, you find the code to upload to the Arduino, to be able to connect to the Bluetooth module that is connected to the Arduino Microcontroller

Figure 5

The Bluetooth module utilizes the code above in figure 5 to connect to the Arduino. This code is uploaded to the Arduino microcontroller to recognize the serial communication with the Bluetooth module.
The Bluetooth is connected to the Arduino which is powered by a computer. The Bluetooth module’s red LED blinks when the module is turned on, the LED stop blinking when communication with Android device is established.
To pair the module with the Android device go to Settings >> Bluetooth and select the HC-06 module and type in the default pairing code: 1234.
In the Arxterra application, ARXROBOT the Bluetooth symbol on the top right corner is selected and tap connect to the paired device the Bluetooth module HC-06.
Once the communication is successfully established; the Bluetooth symbol on the top right corner of the ARXROBOT app turned blue (white when there is no connection) and the red status LED on the Bluetooth module stop blinking. The established communication is shown in figure 4 where the red status LED is on.

4. Confirm Bluetooth communication by turning on 4 LEDS on the breadboard via the joystick on the Arxterra app

The Velociraptor shall be able to walk forward and turn when the robot detects obstacles in order to avoid a collision. Therefore, the joystick on the ARXROBOT qualifies as the best solution for control pad as it provides four buttons of control. The joystick that’s made up of four buttons makes its possible to attach one command to each button, ie. four commands: forward, turn left, turn right and backward. However, the 4^th button is not necessary, as we don’t intend to implement a backward walking command. In order to access the four different buttons, a simple code turning on four LEDS was written in the Arduino IDE, so that the forward button in Arxterra app will turn on LED attached to pin 8 and so on. This test was made so that the Electronic engineer decode the signal into subcommands of move forward, turn to either side etc.

Figure 6

Figure 6 displays the Arduino IDE code that will control each LED by one of the four buttons on the joystick on the Arxterra app in the order of:

Forward button will turn on LED attached to pin 8
Right button will turn on LED attached to pin 9
Left button will turn on LED attached to pin 10
Back button will turn on LED attached to pin 11

Note: Before uploading the code to the Arduino remember to detach the Bluetooth module from the breadboard as it will interfere with the upload and causes error. Re-attach when the code finishes uploading.

Click here for the video showing the communication between the Bluetooth and the Arxterra Application.

References:

Spring 2016 3D SMD: Geared Stepper Motor Trade-Off Study

April 2, 2016/in 3D SMD/by BaoDoan

By Bao Loc Doan (Project Manager)

Requirement L2 – 3: Makeblock XY Plotter motors shall be modified to 0.05 mm error tolerance.

Table of Contents

Introduction

The Makeblock XY Plotter came with two (2) Makeblock 42BYG stepper motors. The stepper motors control our x-axis and y-axis movements. Geared stepper motors were given as a suggestion to replace our current x and y axis stepper motors for higher accuracy. After testing the current stepper motors and presenting our PDR demo, it was agreed that the movement of the x-axis and y-axis are too slow.

Discussion

Figure 1 – Determining geared stepper motors (reference link at the end)

Our current stepper motor are bipolar stepper motors. Normally, these give more torque at low RPMs, while unipolar stepper motors spins faster for the same motor and power supply. The Makeblock Robot Plotter kit came with bipolar stepper motors as well as compatible stepper drivers.

We understand that what we are looking for are top output speed and the acceleration. Purchasing a 5:1 gearbox for the same stepper motor would change the step angle going from 1.8 degrees to 0.35 degrees if using the same stepper motor specs. After research, there is a Makeblock 5:1 geared 47BYG stepper motor that costs 59.99 per unit. This would make our machine increase accuracy by a factor of 5 but is out of our budget and would make our machine slower if we still microstep 1/16th. After obtaining the geared stepper motor, experiments will be conducted to determine if it’s possible to microstep the motors to 1/8th step and maintain desirable error specs.

We know that our Makeblock 42BYG motor does 200 steps/rev and since the driver is microstepping 1/16th, that means it can go 3200 steps per revolution. We could full step the motors, but we would lose accuracy, which is not wanted. The reason why full stepping the motor would make the machine lose accuracy is due to the possibility of the motor skipping a step or losing a step since each step is more distant.

We would like to use the same mechanical parts as we do right now due to compatibility. If introduced to a different motor that may need a different voltage or current, then a different stepper driver would need to be developed in order to step the unit faster and thus spending more resources. Our current stepper motor is rated at 1.7 amps/phase, so in order to properly utilize the current stepper driver, the new motor must be rated at 1.7 amps/phase as well. We would need a motor that can run at least 5 times the motor speed of our current 42BYG, be driven by 1.7 amps/phase, rated 12 volts, and be priced under 35 dollars each (to fit in the budget) to maintain the same speed but have more accuracy.

A stepper motor driver that can step the motor higher could be a fix but our budget is very limited.

Conclusion

A 5:1 geared Makeblock 42BYG stepper motor will work in increasing our accuracy so our device could meet requirement L2 -3 – Makeblock XY Plotter motors shall be modified to 0.05 mm error tolerance. It will satisfy all compatibility requirements as well but budget remains an issue due to the 5:1 geared Makeblock 42BYG motor being $59.99 per unit. The issue in a geared stepper motor lies in that it will definitely make the Makeblock XY plotter move slower than it already is if we keep the microstep at 1/16th. We will conduct experiments where we can find a ratio between accuracy and speed (possibly 1/8th step) that will satisfy our error requirement as well as produce a satisfactory parts per hour speed. However, the speed requirement is not mandatory for this semester and this can be resolved by modifying the stepper driver in future semesters. We conclude that the stepper motor(s) linked above would be a sufficient fit for our needs.

References

Stepper Online: Motors & Electronics. Retrieved April 1, 2016, from http://www.omc-stepperonline.com/high-torque-gear-ratio-51-planetary-gearbox-nema-14-stepper-14hs201504spg5-p-294.html

Spring 2016 A-TeChToP: Arxterra Interface

April 1, 2016/in A-TechTop Generation #4, A-TeChToP Wednesday/by A-TeChToP

By: Omar Rojas (Systems Engineer)

After successfully creating an ECG circuit, the next part of our demonstration was to show that the output from the ECG circuit can be displayed on the Arxterra control panel found on the Arxterra website. The Arduino code for the ECG circuit was successfully implemented in the Arxterra firmware. We also implemented some code for a temperature sensor since the Arxterra Control Panel has a temperature widget within its structure.