Composition of a Robot

Here we present various materials used on a robot

Engines and mechanical parts for cheap

-Batteries new generation Li-Ion / Li-Po and even brand new Lithium Iron Phosphate / A123
-Regulated power supplies

-Contact switches to detect collisions with the environment of the robot
-Obstacle detection by infra-red thanks to proximity sensor IR
-Measuring ambient light to make adjustments in intensity other sensors
-Motorized potentiometer settings for automated
-Knob “softpot” for manual adjustments for
-Counting the time with the DS1307 clock to organize the operation of the robot
-Modules with various sensors compatible with this bus
-Lasers can be very effective beacons


E-cards and microcontrollers
-Small card Arduino to start
-A card with a fast microprocessor Rabbit dedicated to the board: MiniCore RCM5700
-Maps for a more ambitious robot competition: map-based ARM
-Cable programming ISP via USB card APR

Item Description

Mechanical Platform:

The cordless drill,  a quick inspection was in:
10 items NiCd, 1200 mAh
1 engine DC 3-poles that send the heavy-or at least it looks …
1 planetary gear to 2 floors
1 small circuit controlling power of the engine because it boasts an electronic
1 block sector 12V
screw spindle, pseudo ball bearings, and so on.
Here is a photo which consists box (packaged without any protection of course)


Battery and Charger:

Before starting the dish that will be the mechanics that can be recovered in this gear First block consists of 10 cells, weighs 310g and is labeled for 1200 mAh capacity

And the charging circuit? 5W resistor in series with the battery see … no real limitation of the current, much less detection end load. The accelerated destruction of block battery is guaranteed. 


The integration of all is done very simply, we start by removing the screws left in the chuck (yes it unscrews therefore clockwise), a few screws to remove and carcass found in the body of the drill The gearmotor and torque limiter, a power mosfet sink and a printer command and … and that’s all …

Immediately look at how the motor running. Although the function of limiting torque is present, it will be easier to describe thereafter.

The motor looks like this:

To dismantle the housing of the gearbox must remove a ring of the axis of the drill, which reveals the passage of tapered bearings poor to redeem the efforts made drilling axial ball taken sandwidch between washers …

Once the reduction gear box open, there is a nice planetary system with two floors.

The engine in a spiral of steel output (9 teeth). The first floor consists of sprockets nylons (18 teeth) that einkorn on the planet (45 teeth). The second floor is strictly identical with the exception of pine nuts which are all steel. The ratio is therefore 1 / 25.

N-channel power MOSFET

Li-Ion and Li-PO

Lithium Ion batteries and Lithium Polymer are most prevalent. Other battery-based Lithium appeared (the article has already 3 years), such as lithium iron phosphate / A123 Lithium Manganese and Cobalt

These batteries are practical for small, but we must take particular care because the consequences of misuse can be catastrophic.

Disadvantage of Li-Ion and Li-Po:
It has a limit in the rate of discharge and load
To discharge a maximum of 15 times (for best)
The capacity of the battery and loading rate is 1 for 1, so it takes 1 hour to load.
It is fragile, both mechanically electricity.
It is expensive

It is lightweight and offer a low-volume capacity important. It has a self rate of 10% per month, which allows for battery charge always ready to use (such as lead acid batteries).


A Microswitch or ILS (flexible switch blade)  is a miniature switch used for touch sensors for the purpose of racing and other openings of doors.

There are usually 3 dimensions:
Standard (30x20x10 mm)
Miniature (20x10x6 mm)
subminiature (13x6x6 mm)

And 3 kinds:
with leverage (tab)
Without Lever (just the push)
with leverage and roulette

The tongue is a metal plate that supports the switch itself (small button a few mm thick). If the tongue is very long because it is generally intended to be folded (to win shows or to ensure good contact with the element to support it.

The absence of tongue is useful for use at the end of the race or a (size large) is going to touch the push to trigger the switch. Very useful also for use in both directions and avoid twisting tongue in use more than doubtful.

The wheel of microswitch is useful when the object that makes contact in one direction will have to go back the other way (like a door that closes should reopen).

No mystery but a case that does not meet too robotics where microswitches are used at the end of the race. But the principle of the wheel is widely used in the corners of the chassis taken to avoid contact with board or any object

LCD Display

LCD displays text and graphic




Use of lasers:
-tags positioning the robot (calculation details)
-obstacle detection for shooting (alignment and sight)

A laser produces a beam of light that allows straight to aim precisely one place. This light may be in a fairly thin band wavelength (ie color) to be detected by a sensor sensor
adequate light and is more flexible, allowing to encode the signal to avoid interference with a similar source.

The laser is also useful because it takes little space. There are now transmitters lasers and ultra short:

Laser is used in robotics to put a laser at a known location and positioning receiver to one or more positions, playing with mirrors or reflectors to direct the beam.

Therefore, these lasers will exit the system and have a ride in the air that is not master: there is a very special attention to bring to any achievement using lasers. The danger comes from the power of highly concentrated light source that can cause lesions on the skin if it too much and especially in the eyes, even at low power.

USB programmer for AVR

Programmers connect to a USB port, and presenting the system as programmers series.




Cards based on ARM

This card is kind of interesting computing power proposed by the extensions (USB, Ethernet, serial, I2C, PC104) in large number, and the opportunity to develop on a real time, sometimes even Linux.
market research in 2007 and Players-based ARM microcontrollers


I2C clock and calendar

The chip RTC (Real Time Clock) allows for provision of our program an autonomous clock, which can be useful to synchronize the stages of the program without based on the internal counters which are often overloaded.



IR proximity sensor
Using infrared module to detect an obstacle




Ambient light sensor

There are different types of sensor light:
-sensors close
-sensors distance
-sensors ambient brightness
 A light sensor will allow to take into account changes in ambient light around  robots.



Drive 7-segment displays
The 7-segment displays are bright numbers that can lead to choose successive values that will light up. The 10 digits (0 to 9) are broken into segments: each of these segments can be switched independently.

Start with a map Arduino


Main features: Hardware
a map of 5.5 cm by 7 cm with a thickness of 1.5 cm
with a microcontroller Atmel AVR 8bits
connectors for all inputs and outputs
components allowing the use of USB in programming and communication
USB Type B (standard square)
connector power


a single programming code editor, compile and debug
simplified language
and libraries of code to extend the functionality of the micro-controller.

Sharp IR sensor

The family GP2D Sharp is known for use in robotics sensor presence (information returning all or nothing or fixed threshold) or distance measuring (result transmitted in analogue form or by series).
These sensors using optical principle to measure the distance a beam of light infra-red collimated is issued, will reflect on an object in the field of detection ( ” range “) and will in turn hit a bunch of receivers inside the sensor Sharp to assess the distance.

So the first myth is broken: there is no time measurement return of the light beam. The speed of light, even in the ambient air is too fast for a sensor of this size:)
An infra-red sensor capable of measuring a distance between 4 and 30 cm.
3D contactless controller

The aim is to present the principles of capacitive sensors conducting a little experiment implementing in a playful setting. It will then no contact detect the presence and measure the distance to a large object


Analog Accelerometer ADXL311
An accelerometer is an increasingly common in everyday objects: image stabilizers digital camcorders general public, joystick video game console Nintendo Wii, etc. ..


a module for dialogue with sensors on I2C bus serial link from a USB (PC)