Homemade hardwood floor / laminate floor sweeping robot

eagletalontim

So this is something I would like to give a shot using the Prop. Basically the cheapest I can make this thing, the better. I am thinking about getting one of those roller brooms and attaching a robot to one to push it around. Sounds pretty simple to me so I want to start by thinking it all the way through before I move too fast. As of right now, I am thinking about how to charge this thing automatically. Maybe some kind of IR guided dock station....

So, should I use a ultrasonic ping sensor on a fixed position or would this bother my dog? I need this to detect objects accurately so it is a fool proof design. Don't want it getting stuck under the couch for hours while we are away. Any ideas or pointers?

MikeDYur

How about an aluminum hoop, strap rolled on a press, like we did in shop class, making a basketball hoop out of round stock. Use some automotive side molding on it after your finished design, will save on the furniture legs.

kwinn

eagletalontim wrote: »

So this is something I would like to give a shot using the Prop. Basically the cheapest I can make this thing, the better. I am thinking about getting one of those roller brooms and attaching a robot to one to push it around. Sounds pretty simple to me so I want to start by thinking it all the way through before I move too fast. As of right now, I am thinking about how to charge this thing automatically. Maybe some kind of IR guided dock station....

So, should I use a ultrasonic ping sensor on a fixed position or would this bother my dog? I need this to detect objects accurately so it is a fool proof design. Don't want it getting stuck under the couch for hours while we are away. Any ideas or pointers?

Put a conductive strips at 90 degrees to each other a corner. Robot drives forward into the corner and contacts along each side of the robot touch the conductive strips. If needed a sensor or switch turns on power when the robot is present. Simple and reliable.

eagletalontim

kwinn, that makes sense and seems pretty simple. I was thinking 2 arms that stick out of the charging station, one side positive, one side negative. I will have to work on the design of the bot first. Sounds like I have a Walmart trip coming in my near future Going to need motors and wheels too. I was thinking old stepper motors for the drive wheels so it can accurately turn 180 degrees around to make another pass. Maybe I can purchase something from parallax for that part.

prof_braino

I would suggest "weak and slow" during development, if you plan to design for unattended operation. Also, it does not matter if it takes all day if it runs when your out for the day.

It is very wise to think it through a bit before starting , every minute you spend planning saves multiple hours in fixing later.

Consider the Neato robotic design https://www.neatorobotics.com/ These things are awesome but cost $500. We should be able to build these from parts for under $100. Maybe less if its a sweeper rather than a vacuum. This might be a good high level requirements target. If you only get half way it would still be awesome.

These run a very efficient and thorough grid pattern, and have excellent obstacle avoidance.

I believe they use a two point positioning system (the local radio thing), and a laser distance sensor on the bot to measure the room. The lasers I have are probably 10x overkill for a sweeper, but I don't know off cheaper solutions off hand.

I don't think the ping would bother your dog, she could hear it (I can even hear it when by head is directly in front of it), but it doesn't make us crazy.

Consider using IR LEDs and photo detector as proximity sensor rather than actual bump sensors. The guys in the robot club have good success with IR, and bumping looks clumsy.

If you start with mobile part first, and add the sweeper part AFTER you have navigation down, you can use the really cheap Uln2003 Stepper Motor Drive driver and the 28BYJ stepper, these are extremely cheap and slow. Once you get a bot with these to navigate, you can upgrade as needed to something fancy.

eagletalontim

Ok, I just bought a radioshack ultrasonic ping sensor and it works with the code for the Parallax Ping))). The distance seems to be good enough to use for this project so I guess I need to get some motors and 2 controllers next. Thanks prof_braino for the tip on the steppers

erco

I'd pass on those weak little steepers, they are cheap but weak and an exercise in frustration. Use good dc gearmotors or CR servos.

eagletalontim

I already bought 4 of those steppers and controllers for $13 off Ebay and I think I can use them for testing the movement part. Once I get everything finished, I plan on getting CR servos and wheels from Parallax. Maybe Parallax will put them both on sale for me

lardom

Please post your progress. I gave up on a project where I made a ping sensor pan left and right to find the longest distance and then have the bot turn to that direction. When it got to the end of the hallway sometimes it couldn't get out of the corner.
I just ordered a pair of nrf24L01 modules. I plan to put a pan-tilt camera on it this time.

eagletalontim

I just got the servo working with the ping sensor tonight. Still waiting on the motors to come in. I can post the code to what I have so far. Still tinkering with directing the ping sensor in a certain area instead of the 30 degree range it has. I need some kind of enclosure around the sensor to keep it from picking up just the floor.

eagletalontim

Here is the current code :

CON

  _clkmode = xtal1 + pll16x
  _xinfreq = 5_000_000

  PING_Pin = 0                                          ' I/O Pin For PING)))
  LED_Pin = 1
  _SensorServoPin = 2
  _rightServoPin = 3

  DEBUG_BAUD = 9_600

  Sensor_Servo_Steps = 1_990
  _timeStepInMilliseconds = 5
  _updateFrequencyInHertz = 50

VAR
  LONG  range
  LONG  Ping_Servo_control[200]
  LONG  Ping_Servo_Angle

OBJ

  Pst           : "Parallax Serial Terminal"
  ping          : "ping"
  ser           : "PWM2C_SEREngine.spin"
  
PUB Start
  Pst.Start(DEBUG_BAUD)                                 ' 1 cog
  cognew(move_ping_servo, @Ping_Servo_control)           ' 2 cogs
  pause(100)
  dira[LED_Pin]~~

  repeat                                                ' Repeat Forever
    range := ping.Inches(PING_Pin)                      ' Get Range In Inches
    Pst.dec(range)                                      ' Print Inches
    Pst.str(string(" - Angle : "))
    Pst.dec(Ping_Servo_Angle)
    Pst.str(String(13))
    if(range < 10)
      outa[LED_Pin] := 1
    else
      outa[LED_Pin] := 0
    pause(1)

PUB move_ping_servo | frequencyCounter

  ifnot(ser.SEREngineStart(_SensorServoPin, -1, _updateFrequencyInHertz))
    reboot

  ser.leftPulseLength(200 + 0)
  pause(1000)

  Ping_Servo_Angle := 0
    
  repeat
    repeat frequencyCounter from 0 to Sensor_Servo_Steps step 10
      ser.leftPulseLength(200 + frequencyCounter)
      Ping_Servo_Angle := (((frequencyCounter * 100) / Sensor_Servo_Steps) * 18) / 10
      pause(_timeStepInMilliseconds)

    pause(200)
    
    repeat frequencyCounter from Sensor_Servo_Steps to 0 step 10
      ser.leftPulseLength(200 + frequencyCounter)
      Ping_Servo_Angle := (((frequencyCounter * 100) / Sensor_Servo_Steps) * 18) / 10
      pause(_timeStepInMilliseconds)

    pause(200)

PUB pause(Duration)
  if(Duration > 0)  
    waitcnt((clkfreq / 1_000 * Duration) + cnt)
  return

The servo I am using is an old Futaba FP-S148 that came from one of my old planes.

eagletalontim

I am posting an update on what I have so far. I bought some of the High Speed continuous rotation servos and robot wheels from Parallax and have been testing everything on my computer desk. So far, I have been able to detect objects in a certain "angle" from the center point of the bot and slow down the travel speed as an object gets closer. My coding is probably not the best, but it works

CON

  _clkmode = xtal1 + pll16x
  _xinfreq = 5_000_000

  PING_Pin = 0                                          ' I/O Pin For PING)))
  LED_Pin = 1
  _SensorServoPin = 2
  Left_Motor_Pin = 3
  Right_Motor_Pin = 4 
  
  DEBUG_BAUD = 9_600

  Sensor_Servo_Steps = 2_000
  _timeStepInMilliseconds = 7
  _updateFrequencyInHertz = 50

  Stop_Val = 1470
  Left_Full_Speed = 1300
  Limit_Speed_Range = 200

VAR
  LONG  range
  LONG  Ping_Servo_control[200]
  LONG  Move_Servo_control[200]
  LONG  Ping_Servo_Angle
  LONG  Travel_Speed

  BYTE  Direction

OBJ

  Pst           : "Parallax Serial Terminal"
  ping          : "ping"
  ser           : "PWM2C_SEREngine.spin"
  steer_left    : "pwmAsm.spin"
  
PUB Start | shortest_range, loop_count, last_angle
  Pst.Start(DEBUG_BAUD)                                 ' 1 cog
  cognew(move_ping_servo, @Ping_Servo_control)           ' 2 cogs
  pause(100)
  cognew(move_bot, @Move_Servo_control)           ' 2 cogs
  dira[LED_Pin]~~

  loop_count := 0
  shortest_range := Limit_Speed_Range

  repeat                                                ' Repeat Forever
    range := ping.Inches(PING_Pin)                      ' Get Range In Inches
    Pst.dec(range)                                      ' Print Inches
    Pst.str(string(" - Angle : "))
    Pst.dec(Ping_Servo_Angle)
    Pst.str(String(13))
    Pst.dec(Travel_Speed)
    Pst.str(String(13))

    if loop_count => 4
      shortest_range := shortest_range + 5
      if shortest_range => Limit_Speed_Range
        shortest_range := Limit_Speed_Range
      loop_count := 0
    
    case Ping_Servo_Angle
      0..30:
        ' Objects in 30 deg range
        last_angle := 0
      31..60:
        ' Objects in 60 deg range
        last_angle := 1
      61..90:
        ' Objects in front left
        if range =< shortest_range
          shortest_range := range

        if last_angle == 1 OR last_angle == 3
          last_angle := 2
          loop_count++
      91..120:
        ' Objects in front right
        if range =< shortest_range
          shortest_range := range

        last_angle := 3
      121..150:
        ' Objects in 150 deg range
        last_angle := 4
      151..180:
        ' Objects in 180 deg range
        last_angle := 5
      OTHER:

    Travel_Speed := Stop_Val + (Left_Full_Speed * ((shortest_range * 100) / Limit_Speed_Range) / 100)
      
    if(range < 10)
      outa[LED_Pin] := 1
    else
      outa[LED_Pin] := 0
    pause(10)

PUB move_ping_servo | frequencyCounter

  ifnot(ser.SEREngineStart(_SensorServoPin, -1, _updateFrequencyInHertz))
    reboot

  ser.leftPulseLength(200 + 0)
  pause(1000)

  Ping_Servo_Angle := 0
    
  repeat
    repeat frequencyCounter from 0 to Sensor_Servo_Steps step 20
      ser.leftPulseLength(200 + frequencyCounter)
      Ping_Servo_Angle := (((frequencyCounter * 100) / Sensor_Servo_Steps) * 18) / 10
      pause(_timeStepInMilliseconds)

    pause(100)
    
    repeat frequencyCounter from Sensor_Servo_Steps to 0 step 20
      ser.leftPulseLength(200 + frequencyCounter)
      Ping_Servo_Angle := (((frequencyCounter * 100) / Sensor_Servo_Steps) * 18) / 10
      pause(_timeStepInMilliseconds)

    pause(100)

PUB move_bot
  dira[Left_Motor_Pin]~~
  outa[Left_Motor_Pin] := 0
  Travel_Speed := Stop_Val
  Direction := 0                                        ' 0 = Forward, 1 = Reverse
  pause(1000)
    
  repeat
      outa[Left_Motor_Pin] := 1
      pause_ms(Travel_Speed)
      outa[Left_Motor_Pin] := 0
      pause(20)


PUB pause(Duration)
  if(Duration > 0)  
    waitcnt((clkfreq / 1_000 * Duration) + cnt)
  return

PUB pause_ms(Duration)
  if(Duration > 0)  
    waitcnt((clkfreq / 1_000_000 * Duration) + cnt)
  return

The next step is to build the frame for the test bot out of my Erector set parts and hope it fits I will then begin trying to figure a way for the bot to go around an object and continue in the same path it was originally traveling. If I can have the bot detect the room edges and work a pattern from there, that should be optimal. A lot to ask for, but we shall see what I come up with.