Arduino-based robot with IR radar

The robot prototype in this Instructable is my second Arduino-based "slumbot" which is an autonomous robot. It's attached together with household items and scraps. The robot "sees" with an IR scanning sensor rotated by a servo. It looks left, forward, and right for obstacles and distances then decides where to go.

The code name for the robot is Faz3a-X. Faz'ah is slang for a sudden collective fit of rage and lunacy :)

After reflecting on my design themes for this and my other robot, words such as junkyard and Mad Max come to mind.

So let's get started.

MAIN PARTS
- Arduino UNO: $28
- Turnigy TG9e servos (2 modified for continuous rotation): $2 each = $6
- Sharp IR sensor GP2Y0A2 for about $14
- Arduino prototyping shield is optional. You can use a mini breadboard: $15
- 9V battery and pack $3
- 6V Alkaline or 4.8V NiMh 4 X AA batteries and pack $4
- 10uF cap for IR sensor: $0.2
- 0.01uF ceramic caps for for servos X 3 = $0.30

TOTAL: about $70 (in Jordan, expect to pay almost double after shipping, handling, tariffs, taxes, clearance fees)

PLATFORM
- External 3.5" USB hard drive enclosure
- Table leg slider pin (caster)
- Toy car wheels X 2
- Construction set parts for wheels axle and servo mount

TOOLS
- Velcro (what a great invention for prototyping)
- Paper binders/clips
- Rubber bands to give plastic wheels traction
- Stapler to staple rubber bands
- Glue
- Tape, single and double sided
- Wires

WHAT'S NEXT
Next phase of this prototype will involve refining the attached Sketch for better radar/movement coordination and finer obstacle detection instead of the simplistic Right, Front, Left scanning algorithm used here.

Also, the robot platform needs to go on a diet to shed a few ounces but to do it with household items or office supplies. As in my previous robot project, in which I used Arduino to control a cheap toy car, I try to make sure as much of the robot as possible is made up of readily available items in Jordan considering commercial robot parts are nonexistent in local markets and the tariffs and taxes (corruption money) and shipping costs would discourage most Jordanian Makers from pursuing their robot projects.

Step 1 The robot IR radar module

I made use of the plastic cover of a MiniDV tape as a mount for the Sharp IR radar. I used a drill pit to make the screw holes, and sand paper to taper the edges of the plastic cover. It's a rough job but it works.

The servo spins the IR sensor left, forward, and right and reads distance in each direction. In this project, the robot will turn in the direction where there's more space.

I used construction set parts to create a mount for the sensor and servo.

In the video below, I test the IR radar scanner connected to the Arduino and rotated by a TG9e micro servo. It's sending back distances for each direction.

With a piece of Velcro attached to the bottom of the mount, using glue, I can affix the whole radar mechanism on the robot platform and change its position with little hassle.

Comments

[filip10]

can I use a sharp GP2Y0D810Z0F 10cm sensor for this robot ?

[techbitar]

I see no reason why not. there might be some design considerations. best thing to do is to compare specs of datasheets if the only difference is the distance that this could be a plug and play process so to speak.

[Higgs Boson]

did you need to make a H bridge to get one of the motors to run backwards when it turned, or did one just remain stationary while the other ran when it turned?

[techbitar]

I did not use motors. I used servos which I modified for continuous rotation. I can then rotate the servos clockwise or counter clockwise. So no h-bridge was used. An Arduino can power and drive a servo directly.

http://www.arduino.cc/en/Reference/Servo

[Higgs Boson]

Okay. Thank you.

[techbitar]

Opps! I forgot the other part of your question. To make a turn, I use differential steering techniques. Basically, differential steering means spinning each of the two wheels at different speed/direction/duration to achieve a desired turn angle. There are many factors that determine speed/direction/duration values for each wheel such as wheel material, floor material, wheel size, etc I had to wrap rubber bands around the cheap plastic wheels to give my robot better traction which also meant I had to adjust my values for spin speed/direction/duration. If I moved the robot to a shallow carpet, I would have had to adjust those values again. That's because my code is very basic and does not calibrate the wheels automatically for any change in traction. It would have been overkill for this project.

[aefields]

Proper terminology is important. I'm searching for RADAR. Infrared is not radar. It is LiDAR. Please fix your title so others aren't misdirected.

[techbitar]

Thanks for the note. Both uses of the word are correct.

Radar is a mechanism of object detection using electromagnetic waves. IR is just a band along the spectrum of electromagnetic waves, along with visible light. So radar is all encompassing.

http://en.wikipedia.org/wiki/Radar
http://dspace.mit.edu/bitstream/handle/1721.1/4145/RLE-TR-610-36353301.pdf

LiDAR is commonly used with laser detection but also includes ultraviolet, visible, or near infrared, all of which are electromagnetic waves.

http://en.wikipedia.org/wiki/LIDAR