Jamie's Robotics Projects

Introduction

The M-288 Intelligent cleaner (also previously known as "SU210" on ebuyer and "AT-0410 Intelligent cleaner" from the manufacturer, Guangzhou Huahong Industry Development Co., Ltd.) is a low-cost, autonomous robot vacuum cleaner.

http://www.ebuyer.com/product/127690

 

 

Features

This is cut and paste from the ebuyer description:

Stair Avoidance Detector:
With this detector the machine won’t fall down from platforms or stairs – it just stops, changes direction and carries on cleaning!!.       

Non-Marring Bumper:
When the machine comes across a barrier it rebounds and changes direction accordingly and still carries on cleaning !

Virtual Wall Detector:
With this detector the machine won’t travel over the virtual wall, it just changes direction!

Specifications:       

  • Adapter: AC/DC: 230V   50HZ
  • Adapter Input Voltage: 18V DC/400MA
  • Voltage of Battery : 14.4V (12pcs 1.2V Ni-Cd batteries)
  • Unit average power : 19W~ 25W
  • Suction Power : 2.4W
  • Dust Capacity: 0.25L
  • Battery Capacity: 1000mA
  • Charge Time: 4-5 hrs
  • Working Time:45-60 minutes
  • Product Size: 34x6cm
  • Accessories: Virtual wall unit, batteries charger, rechargeable battery pack spoons, side brush and operation manual

Why did I buy this?!

Answer - for £40 it is a total bargain for a totally self-contained robot. Try buying a chassis, shell, sensors, battery and drive system from a robotics site for anywhere near that!

There is a (considerably) more expensive variant of this robot, which seems to be now coming to ebuyer -

http://www.ebuyer.com/product/132856

..which includes this remote: http://www.goldlucky.com/shoppic/200651014341415266.jpg and a docking charger (the basic model I have just stops unceremoniously when its battery is low).

This one wasn't available when I got mine, so I didn't have a choice!

I have a few thoughts with regards to what to do with it:

  1. Keep it as-is.
  2. Mod it to be programmable (i.e. add another controller) and give it more behaviours like remote-control, docking, etc, etc.
  3. Take out the hoover mechanism (it is beautifully self-contained and would take about 2 minutes to remove it).
  4. Buy another one to mod.

What's inside it?

Here is the outside:

Not too much to see here, except for the 3 room-size momentary push-buttons

 

 

 

Here is the underside, the robot is facing to the left so at the front we have a single wheel, which has a cone-shaped molding flanking it, which allows it to turn and also to ride up over obstacles. The wheel is instrumented and can detect if the (sprung) wheel is extended (optical break beam pair), the robot knows it has falling off something, or has been picked up. 

In front of the wheel we have the underside of the front bumper we have 4 optical switches which can detect ledges. I haven't investigated if the emitters are modulated (probably not due to cost and by virtue of the fact that they are recessed). These are almost certainly wired logical OR.

Behind the front wheel is the 14.4v NiCd (BOO!) 1000mAh battery. It's located well forward for weight distribution; making sure the centre of mass is between the tri-arrangement of wheels, keeping it nice and stable and also to allow good space usage at the rear.

Barely visible, at the left of the battery is a 3-armed rotating brush, which performs edge cleaning (the bristles just step outside the robot footprint to do this). It has it's own drive motor.

Top & bottom of the picture are the drive wheels. These are independently belt driven, quadrature-encoded and have spring suspension and a further optical break beam sensor each to detect if the wheel has come off the ground (when picked up or if it went down a depression and is beached). I am yet to find if these sensors from all wheels are wired logical OR, or if it can differentiate as to which wheel is off the ground. The belt drive is good since it is quiet and absorbs shock, thus preserving the drivetrain.

 

And now the inside:

The vacuum gear consists of a contra-rotating rubber-finned bar and brush head, with a vacuum created at the back end by a DC motor driven impeller. The vacuumed matter is conveniently deposited in a removable particle bin on the back.

Above, we have the inside of the 'lid'. That ribbon cable provides power to the bi-colour LED for status and switch wiring for the 3 room size buttons. The keypad is rubber membrane based.

 

 

 

 

Shown from above now, with the lid taken off, we can see, from the left of the picture (front of robot) to the right (rear of the robot):

The top of the bumper, with 360°-lensed I.R. detector, which appears to be the regular A.G.C. device seen in most remote-control applications.

Inside the bumper, looking left, is an I.R. proximity sensor, again, this is probably not modulated as it is deeply-recessed.

Behind the bumper is the cleverly-articulated spring gear, which allows the bumper to be actuated over its full ~180° bump coverage. When the bumper is actuated, one of two arms attached to it moves and interrupts a break-beam I.R. switch

Next is the top of the battery compartment. Nestled on its edge behind, where all the wires go, is the controller board (see below)

 Towards the top of the picture is the edge-brush drive motor.

Top and bottom are the aforementioned drive wheel springs; the red & blue pair to each motor is their supply and the yellow/white/blue/orange bundle is the wheel encoder wiring.

In the centre, we have the brush-head drive. This is a really nice gear-head, planetary-output DC motor. There is an interesting mechanism just visible in the picture - a pulley near that orange part (planetary gear ring) of this motor and a little piece of cord. This allows the whole vacuum section to pivot, self-level and negotiate uneven terrain (carpets) when encountered.

Lower-right, with the orange wiring is the speaker. Top-right is the on/off switch and charging port and below this, we have the vacuum turbine drive motor. This motor looks a little weedy to me, so this may be a good mod at some point.

The particle bin is located at the left of the lever that says 'press' on it.

 

Here we have a (slightly out-of-focus) controller board. It features L293 motor drivers for the main drive motors and edge-head and power MOSFETs for the brush-bar and vacuum impeller. The main controller is a 40-pin DIL EPROM (reflective-backed label protects quartz window for erasing). As to the manufacturer and processor type - I have no idea! Interestingly, it looks like it has been sanded to remove this information.

The cut-outs on the left and right of the board are where the bumper arms pass through, monitored by the light gates, as previously noted. There are a couple of higher-wattage resistors in there too, probably current sensing of motors and also two sets of flyback diodes around the bigger motor drivers.

Most disappointingly, being that the controller is an EPROM, without a UV box and programmer there is no scope for using it.

I am guessing that if you were to get hold of -or even emulate- the remote control or even selectively trick the sensors, you could maybe do some other stuff with it though.

As for customisation then, you are left with little option but retro-fit a custom controller.

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