Обзор

3pi робот разрабатывался как оптимальная платформа для участия в соревнованиях по следующим дисциплинам: следование по линии и движения по (решения) лабиринту. Он имеет небольшой размер (диаметр 9,5 см (3.7"), вес 83 г (2.9 oz) без батарей) и требует только  четырёх элементов AAA (в комплект поставки не входят). Уникальная система питания выдает на моторы постоянного тока 9,25 V независимо от уровня заряда батареи. Регулирование напряжения позволяет 3pi развивать скорость до 100 см/с в то же время позволяя делать точные повороты и вращения, точность которых не зависит от напряжения батареи.

На данный момент хочется довести до Вашего сведения следующую информацию
При неправильном подключении LCD монитора, а именно при подключении его наоборот (правильное подключение указано на рисунке на коробке, или можно увидеть на сайте), выгорает сам LCD монитор, на данный момент зафиксировано несколько подобных случаев.
Характерные признаки подобной проблемы:
При включении робота одна полоса экрана заполняется квадратами, и далее робот "подвисает", и не прошивается с LCD монитором.
 

3pi робот является превосходной платформой для людей с опытом программирования на C, изучающих робототехнику, а для амбициозных и начинающих изучать С, с 3pi, это может стать весёлым развлечением. В основе данной платформы лежит микроконтроллер Atmel ATmega168 или ATmega328P работающие на 20 МГц. 3pi робот на основе ATmega168 имеет 16 КБ программной флэш-памяти, 1 KB RAM и 512 байт EEPROM; 3pi робот на основе ATmega328 имеет 32 KB программной флэш-памяти, 2 КБ RAM и 1 КБ EEPROM. Популярный и бесплатный GNU C/C + + компилятор отлично работает с 3pi, AVR Studio компании Atmel предоставляет комфортную среду разработки, а обширный набор библиотек предоставляемый Pololu делает простой коммуникацию со всем интегрированным оборудованием. 3pi также совместим с популярной платформой разработки Arduino. Pololu предлагает целый ряд примеров программ, которые показывают, как использовать различные 3pi компоненты, а также реализующие более сложные примеры поведения, такие как следование по линии и решение лабиринта.

The diagrams below highlight the important features of the 3pi. Click on either picture for an expanded view.

For instructions on setting up and programming the 3pi, including sample code, contest ideas, and more, see the3pi Users Guide.

Required Accessories

An external AVR ISP programmer, such as our USB AVR programmer is required to program the 3pi. We offer a combination deal that includes a 3pi robot, USB AVR programmer, and USB cable.

The 3pi is powered by 4 AAA batteries, which are not included. We recommend rechargeable NiMH cells, which may be purchased from Pololu or at a local store carrying electronics.

Optional Accessories

We currently offer two expansion kits for the 3pi that give you room to augment your 3pi with your own custom electronics. One expansion kit features cutouts that let you view the LCD below and allow you to reach the power button, reset button, and ISP programming header on the base. The other expansion kit has no cutouts and instead replaces the LCD, giving you access to more I/O lines and more prototyping space. These kits can be purchased with PCBs that have either black or red solder masks; the pictures below show the black versions.
 

A Video Introduction to the 3pi

To see for yourself what the 3pi is like, please take a look at the video below, which introduces its basic features and operation.

More Pictures and Videos of the 3pi Robot:

The following video shows a 3pi prototype autonomously solving a line maze. It first runs through the maze executing a search algorithm, keeping track of which way it is turning at intersections and discarding paths that lead to dead ends. Once it finds the end, which is marked by a solid black circle, it determines from memory the best path from start to finish and on subsequent runs aggressively drives that shortest path. This is just one example of what the 3pi is capable of.

This unedited video shows six 3pi prototypes simultaneously participating in a line-following exhibition at a local robotics competition. The robots were all programmed independently. Last one remaining on the line wins!

Click here for even more 3pi videos!

The following pictures show the 3pi’s LEDs as it drives around in the dark:

FAQ`s

How does the battery charger connection work? Is there a charger included?

The 3pi robot does not include batteries or a charger. The battery charger connection provides a direct connection to the batteries so that if you use rechargeable batteries, you can recharge them without taking them out of the robot. You will need a charger capable of charging four NiMH or NiCD cells (depending on what you’re using) in series. Such chargers are readily available in hobby stores for charging electric model airplane battery packs. Please note that rechargeable batteries are not required as the 3pi can use regular alkaline cells, but we strongly recommend investing in some NiMH cells and a charger.

I’m ready to order a 3pi, but am wondering what sort of battery charger I need. Any recommendations?

You will only need a battery charger if you plan on powering your 3pi with rechargeable cells. The features you want are ability to charge 4 NiMH cells in series (they are usually in battery packs, not in battery holders like on the 3pi) and to be powered by AC (a wall outlet). In general, having more flexibility (such as the ability to charge 1-8 cells) is nice for future projects. Though we don’t have experience with these particular models, the following chargers look like they should be nice:

Tower Hobbies AC/DC Digital Peak Charger w/LCD

Triton Jr (customer-recommended)

These chargers can be connected directly to the 3pi’s battery charge port, allowing you to charge the batteries while they are still in the robot.

Since the 3pi just uses ordinary AAA batteries, you can buy battery chargers (into which you stick the batteries) at most general electronics stores. For example, a quick search of the Radio Shack web site yields:

4-6 Hr. Battery Charger + 4 AA & 4 AAA Ni-MH Batteries

The downside to a charger like this is that you have to remove the batteries from the 3pi to charge them.

The green (PD7) user LED on my 3pi flickers even though I’m not doing anything with it. Is it malfunctioning?

No, this behavior is normal. To get the most out of the ATmega168’s I/O lines, one of the LCD’s data lines (PD7) doubles as the control line for the green LED, so this LED might flicker when the LCD is updated. As such, the amount of flickering and effective brightness of the LED will generally be a function of the rate at which you are updating the LCD. Note that you can change the state of the green LED without affecting the LCD at all, and using the LCD via the Pololu AVR library will only very briefly change the state of the LED line as needed before restoring it to its previous state.

Can I augment/customize my 3pi by adding my own electronics/sensors?

Yes. The easiest way to augment your 3pi is through an expansion kit, which can comes either with cutouts that let you see the LCD below or without cutouts. The version without cutouts replaces the LCD, giving you access to more I/O lines and more prototyping space. An expansion kit is not required for addition of your own electronics, however. The 3pi robot has a limited number of free I/O lines that can be used as inputs for additional sensors or to control additional electronics such as LEDs or servos.Please see section 10.c of the 3pi user’s guide for more information.

Are wheel encoders included or can they be added to the 3pi robot?

Are there sufficient I/O lines available for encoders? Unfortunately, there is no provision for encoders on the 3pi: we do not have any sensor solution and the microcontroller does not have enough I/O lines. Therefore, the only way to add encoding is to make your own sensor setup and to use an external microcontroller (for example, on an expansion PCB) to do the sensor reading. The secondary microcontroller can communicate with the main 3pi controller using the asynchronous serial lines, which are available for expansion purposes.

I’m adding peripherals to the 3pi that require 5 V. How much current can the 5 V (Vcc) power bus supply?

Because the 5 V goes through two power stages, the answer is not completely clear-cut. The 5 V regulator itself has a 900 mW power dissipation limit, so with a 4.3 V drop from the 9.3 V boost voltage to 5 V, we get just over 200 mA. The stock electronics on the 3pi typically use under 50 mA (however, this depends on what your program is doing, if you are making high-frequency noise with the buzzer, and so on), so you could figure an absolute max of 150 mA, with 100 mA being a more comfortable guideline. However, the boost voltage has a limit of its own of around 1 A, which is dependent on your battery voltage. The motors and IR LEDs also use this supply, so using a lot for your 5 V will affect what is available for the motors. You can almost stall the motors and still have the full boost voltage on the motors in the stock configuration; if you’re also drawing an extra 200 mA for other electronics, the boost voltage will start dropping as the motors approach stall, though this is not necessarily a bad thing since it will limit the stress on the motors and lower the voltage drop on the linear regulator.

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