Hello Everyone.
I am new at robotics and I want to start putting together my first robot.
I will be using a DFRobot Romeo V1 All-in-one Microcontroller (ATMega 328).
I want to incorporate two main functions:
Obstacle avoidance and following a black line path.
I was wondering what ultrasonic and infrared sensors would you guys recommend for these 2 type of tasks?
Also, the Romeo V1 comes with two motor drives. Can I create a 4 wheeled robot with this or do I need to add 2 extra motor driver extensions?
Thank you all.
Hi,
For obstacle avoidance, you can use a Sharp IR Range Sensor. For example this Sharp GP2Y0A21YK0F IR Range Sensor - 10cm to 80cm.
It can detect objects at a range of 10cm (~4") to 80cm (~30") and provide a proportional analog signal to the DFRobot Romeo V1 All-in-one Microcontroller.
As for black line following, you can interface a Line Follower Sensor Array with the DFRobot Romeo Microcontroller.
Like for example this Pololu QTR-8A Reflectance Sensor Array or this Parallax Infrared Line Follower Kit.
Yes, you can. The DFRobot Romeo V1 All-in-one Microcontroller has two channels motor driver outputs with 2A maximum output current.
You can still use 4 DC motors (with a rated voltage 6V to 12V) by connecting 2 motors to each channel.
However, you have to be sure that the 4 DC motors together don’t consume more than 2A current (500mA per motor). Plus, 2 of 4 motors will rotate simultaneously.
This Brushed DC Motor 6V, 11500rpm or this Banebots Brushed DC Motor might interest you.
If you are planning to use more powerful motors, you’ll need an appropriate motor controller.
Regards,
Thanks a lot for the information Brahim Daouas. It has been very useful!
Now, if you dot mind, would you be able to recommend what would be the appropriate power supply required for optimum performance of the Romeo, if considering using just 2 motors (each driving 1Amp)? Or how to figure out this? I am not very knowledgeable regarding the main differences between having 3 or 4 AA or AAA batteries.
Hi,
You can power the DFRobot Romeo Microcontroller in two ways.
Either you power it from USB or from the Motor Power Input.
Powering the DFRobot Romeo Microcontroller from USB will not provide enough current to power the DC motors (USB will provide 500mA maximum current).
To be able to control the DC motors, you might need an external power supply 6V-12V depending on your motors working voltage (maximum rated voltage for the DFRobot Romeo Microcontroller is 14V).
If the DC motors you’ll use are rated for 6V, you can probably use these 6V Ni-MH rechargeable battery pack with this WH-01 Wiring Harness with Battery Connector to power both the motors and the microcontroller.
One alkaline battery, like AA or AAA, has a nominal voltage of 1.5V. So 4 of them connected in series will have 6V nominal voltage.
If you power the DFRobot Romeo Microcontroller and the motors seperaterly (using USB), keep in mind to remove Vin=M jumper.
Regards,
Truly appreciate the information.
Thank you!
Hello Again!
Hope you are dong well. I was hoping you could help me out with a couple of questions:
- I thought Romeo V2 is an improved version of the V1. If so, why is it cheaper?
- would you recommend considering using a twin motor gear box for this project and microelectronic (Romeo V1)?
- Just to be clear, I can use any motor with the Romeo (for a two motor robot) as long as the voltage for each doesn’t exceed 12 Volts and the Current for each is no more than 1 Amp. Is this correct? I am asking because I want to get the fastest motor possible to use under the micro-controller constrains. Any recommendations for this?
Thank you again very much for your time.
Hi,
]The Romeo V1 uses an ATMega328 microcontroller. Romeo V2 is an improved version of the V1 and it uses an ATMega32U4 microcontroller. The Romeo V2 improves the power supply and supports Stepper Motor control./:m]
]You could use for example two of the DFRobot 6V,180rpm Micro DC Geared Motor. Please take a look at the DC Motors we offer./:m]
]On the manufacturer’s datasheet the Romeo V1 Motor Input Power Supply is rated for 5~12V. For the Romeo V2, the input range is from 5~23V. The motors current draw should not exceed 2Amps for the V1 and V2. Please take a look at this link. /:m]
Regards,
Perfect. Thank you very much!
Hello Again.
I decided to purchase the DFRobot 6V,180rpm Micro DC Geared Motor that you previously recommended. However, I noticed that under specs, it says that this motor has a max stall current of 2.8 Amps. Since the Romeo micro-controller is only able to deliver 2 Amps, why wouldn’t this be a problem?
Thanks in advance!
Hi,
When choosing a motor controller, you have to consider one that will provide current equal to or above the motor’s continuous current consumption under load and not the max stall current (the DC motors should never be stalled).
Some of motor manufacturers provide the motor’s stall current and not the continuous current draw under load.
If you cannot find the motor’s continuous operating current, a simple rule of thumb is to estimate the motor’s continuous current at about 20% to 25% of the stall current.
Regarding the DFRobot 6V,180rpm Micro DC Geared Motor for example, the maximum stall current is 2.8Amps so the continuous current under load shouldn’t exceed 700mA.
Therefore, this shouldn’t be a problem using the Romeo microcontroller.
Regards,
Thank you very much for the explanation. Makes perfect sense now.
Why dont you start with an Open source robot like this?
jjrobots.com/projects-2/b-robot/
You can add a sonar, use its ancillary devices for other robots and control it remotely from your phone.
Cheers!
Yes, you can. The DFRobot Romeo V1 All-in-one Microcontroller has two channels motor driver outputs with 2A maximum output current. You can still use 4 DC motors (with a rated voltage 6V to 12V) by connecting 2 motors to each channel.
However, you have to be sure that the 4 DC motors together don’t consume more than 2A current (500mA per motor). Plus, 2 of 4 motors will rotate simultaneously.