Cbot - Plant Maintenance Robot 1 Preliminary Development Projects Updated 11/8/15 Key Search Words: ROBOT, ROBOTICS, ROBOTIC VISION, ARTIFICIAL INTELLIGENCE, AI Final Report
CBOT-1: Plant Watering Robot
Certainly one of the most complex robots I have ever built, this robot was not only the first to use the highly advanced CCS-C compiler for writing the code which controlled the robot, and employed navigational techniques that had not been used before in any of my previous robots. As many of you know, the robots construction and programming was done incrementally, each step building on the last to bring together the complete robot. Here you will find a overview of worked and what did not, and some thoughts on the future next generation of Plant Maintenance Robots.
What worked really well
CHARGING CONTACTS AND DOCKING PLATES
- The brass contact plates combined with the guitar string feelers made a very effective and reliable charging contact system.
- Set for the lowest power level, the robot could see the charger over 4 feet away and almost always nailed it right in the center!
AUTO FILLING PUMPS AND CIRCUITS
- Using a 1 khz water pump ON signal worked great, and did not have any interference from sunlight or overhead lighting.
WATERING TUBE AND FUNNEL
- The idea of watering a single funnel with distribution tubes rather than try to hit every plant worked perfectly. The watering tube was always within 1 inch of the center of the funnel when the water turned on.
SONAR DISTANCE NAVIGATION
- Set for one inch accuracy, this was good enough to hit the funnel every time. twice that good would have been even better.
WATERING ON TIME SELECTOR
- This worked so much more reliably than the color computer I tried at first, which blew up before it ever made it into the robot. I finally set the selector for 4 seconds for best results.
ADAFRUIT DIGITAL MAGNETOMETER
- This is the biggest HOG of program space in the robots memory, but never got lost when used as an indoor compass.
WATERING TRUTH CUP
- This small cap was suspended inside the watering funnel on the planter and filled with water each day IF the robot watered the plants. Id dump it every evening, and this let me know when I wasnt around to see it that the plants DID get watered.
What did NOT work very well
ORIGINAL DRIVE MOTORS
- Awful cheap ($22) Chinese motors that were a bit too fast anyway. One kept on slowing down every day for months and the other one day completely siezed up!
AUDIO SOUNDS SYSTEM
- Poor robot had a hard time making sounds with such a tiny speaker. Oh well.
USING DUAL GEAR HEAD MOTORS FOR DIFFERENTIAL DRIVE
- Nearly all house hold robots use DC gear motors to drive them about. No matter how I adjusted them, the constantly changing water load made one motor always go slower than the other, making the robot bank right or left and sending off course.
WATER LEVEL INDICATORS
- The first one I made worked for a week and then got coated with lime and always read incorrect water levels. The second one, now in use is better but sometimes still reads "phantom" water levels.
BACKLIGHT ON LCD DISPLAY
- After a while the New Haven transrelfective display would not turn off its backlight. Really sucked power at night!
RAN OUT OF PROGRAM MEMORY
- A HUGE problem, I almost could not make the robot work with the very limited 8k of program memory. The big problem was the digital compass had to have extensive math libraries tacked on to make it work, and left me little for the robots movements. A separate compass chip will be in the next version.
DOCKING BACKUKP FLAG
- In theory, a small flag would fall when the robot backed up to let me see on the web cam for the room that the robot left the charger for the day. Sometimes it didnt fall down.
Future changes for the next version of CBOT.
The next upgrade will occur after the plants have been harvested for peas and radishes. The primary goal is not only to free up all the processor memory by offloading sensor data to separate processors, but to improve the accuracy in reaching each planter and increase the number of planters to include a more extensive robot garden project.
Electronic / Mechanical improvements:
-- Replace drive motors with stepper motors and add driver boards
-- New robust wheels
-- Amplified audio system for sounds you can actually hear
-- New sound chip for advanced sounds
-- Improved water level indicators
-- Fix backlight issue
-- Auto resetting docking flag
-- Add high accuracy sonar chip
-- New serial compass chip
-- Better battery mounting
BACK TO ROBOT PAGES HOME
Interested in learning more on the development of this robot? Here are previous uploads - LATEST AT THE BOTTOM:Previous Articles 1. Plant watering sensors 2. Cbot basic concepts and project definition 3. Docking sensor, battery charging and FSM explained 4. Development of the water tank, pump and feed mechanism 5. Development of the reservoir refill system 6. Incorporating the Triple axis magnetometer for compass navigation 7. Installing the final components - Bumper Switch Array 8. Night - Day - Night Detection to trigger watering task 9. Planter Water Distribution System for Autonomous Watering 10. Plant progress upstairs after two weeks! 11. Two months in operation