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

Austin D.
user 116643312
Roanoke, VA
Post #: 3
i'm looking for a programmer that can help me with my"segbotler" a self balancing robot that can help me with everyday chores. the robot runs off 2 24vdc worm-gear motors and a sabertooth 2x25 motor controller with arduino uno r3. I have never been able to understand programming and have no desire to learn the basics do to my learning disability. the best i can do is copy what someone else has already coded and not learn anything from it. I'm looking for someone that can do the programming for me for little to none in return. im willing to pay a negotiable amount but my limit is low. i really want to have this and i know nothing in this world is free, or easy, but i can not do this alone and no one online are willing to help so I've resorted to local which has never worked for me either.
Tim B.
Tim_Brandsberg
Goode, VA
Post #: 3
Austin,

My name is Tim Brandsberg and I am a Mechanical Engineer who is nearing retirement. I have been involved with electronics as a hobby as well as professionally for over half of my career. I started to experiment with small Arduino projects a couple of years ago as a hobby/adult self-learning experience. One of the projects that I have been wanting to try was a small segway self balancing robot. At this time, I have not yet begun this project as I have more to learn and understand and more parts to obtain. However, I have been collecting code samples from the internet to help me get started when I am ready. Your project sounds very interesting, and I would like to help you with it since it would push my pace of learning.

I live about half-way between Lynchburg and Bedford, just off RT. 221. This is about a 30 minute drive from downtown Roanoke. I don't know how far you are from there. I have attended several of the Roanoke Robotic meetings, but not in recent months due to vacation travel conflicts and three surgeries in three months to replace a hip joint and a knee joint. I am on short-term medical leave until early January. Although my wife and I will be out of town for a couple of outings, I might have some time to help.

I don't know if you have attended any of the club meetings that I did, but if you did, I was one of those who always had my own two cents to add to the discussions.

How far along are you in the mechanical portion of this project? Do you already have the motors and controller, and have you started the construction of the structure yet? You mentioned that you would like to have this to help you with everyday chores. Do you intend to use this as an alternative to a wheelchair or other walking aid?
I ask this question because I recently saw a Youtube video of a home-made Segway-like device that the operator sat down on while riding.

Please let me know a little more about yourself, the current state of your project, some of your objectives for the end product. If you want to contact me directly, my personal email is tabrandsberg@gmail.com.

I will not be at the next robotics club meeting on December 7, but if you attend, there are others in the club who could provide some support in the mechanical and power supply areas as well.

Looking forward to hear more from you,

Tim Brandsberg.


Gary Y.
user 38202422
Roanoke, VA
Post #: 21

I've seen LegoBots do the self balancing, the user manually balance the LegoBot, then the control takes over by moving the wheels back & forth to maintain center of balance. There must be a sensor to know how to keep it centered.
The legoBot design is published http://makezine.com/2...­
Another example is :
http://www.geology.sm...­
Here is another cool reference.
http://www.geology.sm...­

Here is a link for a design using an Arduino: http://forum.arduino....­

Before programming, there must be a control plan.
#1 - what tells the robot where to go ? forward, reverse, turn left or right, and add the balance control with that wheel control. Autonomous/ GPS, interface to a radio control, control from smart phone - website, etc.
#2 Sabertooth allows you to control two motors with: analog voltage, radio control, serial and packetized serial. http://www.dimensione...­ The designer needs to define the interface from sabertooth to , most likely serial to avoid analog drift & noise.
#3 - what is the emergency stop system , in case the control goes haywire ?
#4 - Arduino Uno is a nice control, it doesnt multitask and is memory and IO limited. A self balancer could be done, and maybe move in 2 dimensions. Additional vision systems, gyro sensors, accelerometers, GPSs, bluetooth / wireless ethernet, acollision avoidance sensors, robots claws, etc probably needs a bigger CPU.

Summary: Think big, start small.
Try a self balancing robot first, just that will impress people. Then add to it by moving to spots, avoiding running into walls.
Try a small horsepower prototype model before building the full scale godzilla size version.

For sure a self balancing / unicycle would be so cool to show at our club's public events.

Lets see if one of the club members can build a "30 minute" LegoBot version and present at a club meeting.
An Arduino based R2D2/Android looking self balancer may be a neat design series to explore at club meetings.
Austin D.
user 116643312
Roanoke, VA
Post #: 4
i relpied to you via email but if you didnt get it its because of the pictures btw something i didnt include in the email is that ive heard of you im pretty sure they talked about you at the last meething said that if you were there you could have helped with something
Austin D.
user 116643312
Roanoke, VA
Post #: 5
i want to control it with a bluetooth shield but i cant afford that right now so i have a vex microcontroller and i want to drive it that way but i dont know how to use the arduino with the vex controller or use the vex with the arduino but i dont need to to go right now im not thinking that far ahead i just want it to balance and then i sit on it and lean forward to go back and back to go forward and that will be my fmoment of joy when it finally does something other than sitting in to corner of my living room in pieces or lean up against something
Tim B.
Tim_Brandsberg
Goode, VA
Post #: 4
Austin and I have started some side discussions on my helping with the project. the IMU he is buying for the project is one that I already have and I have been collecting code snippets for balancing Arduino robots. I am considering developing the code using a small bot and and the imu.

Gary Yohe's comments are very good and he is a good source of assistance in the electrical engineering area.

Tim Brandsberg
Gary Y.
user 38202422
Roanoke, VA
Post #: 22
Excellent Tim, thanks for the mentorship & update.
Austin's idea for the bot will be really great project and also for a club showpiece.

I picked up an ADXL345 inclinometer myself for the satellite antenna tracker project, but havent used it yet. The HMC5883 compass I used for the azimuth motion is inaccurate, slow & noisy.
Would like to get ur feedback on the IMU you guys use.

For giggles I estimated under ideal conditions: if Austin got 24V motors with 25A full load amps (max rating of the Sabertooth) and 2000 rpm motors with 100:1 gear ratio, each axel would generate 190 ft lbs torque. That somewhat matches the Sabertooth claims of using for a 300lb hobby robot still with 200% available torque to accelerate ( probably not for long tho). So the Sabertooth driver card can do it. The motor - gearbox combos are critical, ( and also you need to figure out the wheel size to go with it ? )

Your mechanical knowledge will be really useful for a rider robot to make sure the learning curve is short.
I have just rebuilt the antenna tracker azimuth mechanics for the third time, ever increasing the beef to keep it from breaking. It worked good testing, the minute I tried really using it, BREAKDOWN shock .

Is there any thought to motor load sharing to help keep it running straight without checking direction ? Ought to also use automotive fuses in the motor circuits for instantaneous short circuit protection, even tho the sabertooth already has electronic overload protection ( on itself , not the motor)
The Sabercard is also a regenerative control, so can make the system pretty snappy :-)

Dont need a segwaybot to run @ 60 mph, and need enough torque to keep balance with a 200 lb rider ( and the 50lb PC on their lap ). The mechanical engineering is intriguing. It would be fun to add sensors to automatically chase the cat devilish

I hope you guys are willing to post progress, calculations, lessons learned, and program for the club, and also present the first prototype when ready.
Very cool guys !
Tim B.
Tim_Brandsberg
Goode, VA
Post #: 5
Gary,

Austin is designing his project around one that he saw in instructables. To me he is following the plans closely. I like the fuses idea.

Tim
Austin D.
user 116643312
Roanoke, VA
Post #: 6
i started with the basic idea of the "sitway" from the instructable but then i used wood and nails and also made it 1 3/4:1 scale to the original. also i might use the fuse idea but i do need to limit the ammount of money i spend on the project so far ive invested about 400 more or less. i just got the accelerometer in the mail yesterday. im out of town right now so i do not have access to the information on how many rpm's the motors are but i do have 2 24vdc motors with an unknown rpm and a 12vdc motor 2400rpm that id like to do something with eventually i was thinking of making the top spin that way when i mount things to it they can face any direction. ill post some pics soon for all of this forum to see.
Austin D.
user 116643312
Roanoke, VA
Post #: 7

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