After some searching I couldn’t find anyone that had attached the new mico gear motor encoders to the 3pi platform. At the black friday sale I picked up a little bit of everything and spent an hour putting it together this morning. It is an intermediate soldering job to do the following. The good news is that everything fits.
1. Remove the stock 30×1 3pi motors. (Unscrew the plastic motor cover, and then desolder the two motor pins from the 0.1 inch pins.
2. Replace them with the 30×1 dual shaft motors. http://www.pololu.com/category/141/micro-metal-gearmotors-with-extended-motor-shafts
3. Insert the encoder electronics module. http://www.pololu.com/product/2590
4. Solder at least 4 wires to the module. I used wires terminated in standard 0.1 inch pins, but you can also use 2mm cable as the pin spacing is 2mm instead of 2.54 mm. This is a bit fiddly after two cups of coffee. (Hey pololu, dump the M1 and M2 and give us a 2.54 connector for fat american hands. ( I really wanted to solder a 2.54 mm male header here. Yes I have 2mm headers from working on so many korean projects, but who else does!)
5. Hook up power and ground and check the output on a scope.
It is going to be a bit tricky as it would be nice to have one interrupt per encoder, but I will steal IO off the LCD to make this work, the other interrupt is tied to one of the motor control pins. I will probably end up using the pin change interrupts.
5. Hook up power and ground and check the output on a scope.
WIN USA in collaboration with Mt. San Antonio College presents:
MINI URBAN CHALLENGE and Robot Showcase
December 7th from Noon to 3PM.
Robots from all over all over the East San Gabriel Valley will descend on Mt. San Antonio College for the first annual WIN USA Mini Urban Challenge. Participants will compete with their autonomous robots to drive through a model city completing missions that challenge both novice and expert roboticists.
- Mini Urban Challenge Competition
- Sumo Robot Competition
- Line Race Competition.
- Tour of the Mt. SAC exploratorium
- Exposition of Mt. SAC robotics team VEX robots
- Demonstration of Mt. SAC Intelligent Ground Vehicle.
- Open Source WIN robot demonstration
- Open Source WIN robot will be available for sale
Rules are available at http://profmason.com/?p=17795
Schedule for the Event:
- 12:00 Check In
- 12:15 Opening Ceremony
- 12:30 Line Race
- 12:45 Sumo Robots
- 1:15 Break / Lunch
- 1:45 Robot Exposition
- WIN Robot
- VEX Robots
- IGVC Robots
- 2:15 Mini Urban Challenge
- 2:50 Closing Ceremony
Welcome to the Mt. SAC Roboexpo V.
Mt. San Antonio College is proud to host a State Final Qualifying VEX Robotics Competition (VRC) event for the fifth time . This is a State Final Qualifying event and will have 5 state qualifying spots available to top finishers.
There will be two arena’s running for competitions in addition to a practice arena outside the pit area and a VEX College arena also available for practice. Skills and Programming Challenges will run in the competition fields mid-day after the qualifying matches and before the the semi-final matches.
The event will start promptly at 9AM. Door open at 8 AM and please arrive by 8:30 AM for registration. The event organizers will work hard to have the event over by 5 PM. Be sure to register for Skills and Programming Challenge when you arrive at the event so that the competitors can queue in a timely fashion. Free parking will be available in nearby lots.
The world champion Robomagellan team will be on hand to demonstrate their autonomous outdoor navigation platform and talk about their preparations for the Army / AUVSI Intelligent Ground Vehicle Challenge. The gold medal winning humanoid robotics team will be present to talk about the challenges of humanoid robots. The developer of RobotC compatible VEXduino will be present and giving out free VEXduino PCBs which allow your VEX sensors and motors to be connected to the Arduino platform. There will also be representatives from local aerospace to talk about opportunities in Robotics.
Participants will be asked to sign a waiver as there will be a feature article in Robot Magazine on Roboexpo V. Please be ready to promote your school and team to be included in the article.
Map to Venue
I was asked for an opinion and for help sourcing an inexpensive robot kit. I just happened to be playing with the L9110 hbridge boards so it seemed like time to revisit the topic.
First what are desires for a basic robot kit? It depends on the application. There are a variety of competitions in the local area. I have co-organized the Mini Urban Challenge for the last two months at RSSC. The following competitions are pretty standard:
- Mini Sumo
- Line following
- Table top navigation
- Mini Urban Challenge
These competition require the following sensors:
- wheel encoders
- line sensors (prefer multiple)
- color sensor
- distance sensor
Thus our sample robot will have the following:
- A lasercut chassis
- A pair of wheels in differential drive configuration
- Wheel encoders
- A line sensor array
- Motor controllers for the wheel motors
- Arduino UNO
- AA battery pack
- Sufficient wire to put it together
Here is the BOM with sources.
- 2WD smart Robot Car Chassis Kit (Contains laser cut chassis, wheels, gear motors, hardware, encoder disks and battery pack) $11.59
- Encoder module compatible with Chassis Kit $2.13 EDIT: Unfortunately, this module doesn’t fit the laser cut chassis we ordered, so I am forced to recommend purchasing two of these modules. $6.40 for two. Either you need to order a 100 mm wide chassis (the above chassis is 120 mm wide) or the dx modules above.
- Line Sensor Array $4.84
- Dual Motor Driver (HG7881 / L9110 based) $1.82
- Arduino Uno $9.45
- Male to Female 40-Pin DuPont Breadboard Jumper Wires $2.82
Optional items for the robot:
- TCS3200 based color sensor $5.69 (Allows color detection for the mini urban challenge)
- metal ball caster $3.99 (Greatly improves tracking of the robot.)
- HC-SR04 Ultrasonic/Sonar Distance Sensor Module $1.96 (Distance sensing from 0.1 m to 3m)
- HC-SR04 mounting bracket $1.69 (A mounting bracket to be purchased with the distance sensor)
- IR Remote Control Kit $2.88 (Allows remote control of the robot using a TV type remote)
- Bluetooth Module for Remote programming and control $6.81 (Allows bluetooth remote control of the robot)
- Sensor Shield $5.59 (Allows easier connection of sensors to Arduino.)
- Upgraded Motor Driver $4.39 (This is L298N based and can handle roughly twice the current of the L9110 based motor driver)
Just met with folks from SmashBots, Saturday Night Fights and National Tooling and Machinists Association about organizing a calendar for Combat Robots in So Cal for the next year. The first event will be Ant Weight robots at OC Mini Maker Faire on August 17th. Event is open to all participants and robots must comply with the RFL ruleset.