Romeo v2 + 4WD Pirate - Power question- DFRobot Forum

2014-03-04 13:32:05 That is all right.
The maximum voltage of "VIN" is about 12V.
Generally, if the voltage is higher than 6V, it will be enough to drive the microchip.
So 7.4V is O.K.
Please connect positive of battery to "VIN" port. The other are right Grey.CC

2014-03-03 18:48:27 Then ok, I understand that what did this guy on his link was good.

[img]http://1.bp.blogspot.com/-LiScElyKC_o/UqoWNTNxd8I/AAAAAAAAAkI/SkRVVOfPHY4/s1600/power.png[/img]

You advise a 7.4V battery for the microcontroller when this guy uses 11.1V. What is the ideal and maximum voltage for the VIN/GND that I connect for the microcontroller?

Please find attached a schema of what I will do. Do you confirm it's ok like that?

Sorry for asking many times but I want to be sure, don't want to burn the card.

Antonio
Antonio

2014-03-03 17:11:41 Oh! Sorry, I made a mistake.
You are right.
"M_VIN" is connect to L298N chip directly.
Whatever "ON" or "OFF", it always connect.
Sorry again.

And for the microchip, Vin is better. The 7.4V lion battery also is O.K.
You could use two batteries, one for motor, and one for chip.
If you are using two power supply, please the switch to "OFF".

Grey.CC

2014-02-28 16:53:07 Thank you for the answer, but I don't fully agree with what you said.

2 cases :
- switch is "ON": the microcontroller [u]is[/u] supplied by the motor supply (M_VIN)
- switch is "OFF": the microcontroller [u]is not[/u] supplied by the motor supply (M_VIN)

So what he did was right, put the switch on "OFF" and supply the microcontroller by another source.
This is also what I would like to do, this is the goal of this switch.

So with 2 power systems :
- Motor side : clear for me, a 7.4V 2200mAh battery pack should make the work
- Microcontroller side : I can use the microUSB, so a cable to the computer, but I need the robot not to be connected. In this case what battery should I take for the microcontroller and where to plug it (microUSB? Directly to Vin and GND in the middle of the board?

Thank you in advance. Antonio

2014-02-28 10:39:44 Hello Antonio,

I think he has made a mistake.
The "M_VIN" port is connected "VIN" through a switch.
If he turn off the switch, the 5 AA battery will not support the power.
Actually his power supply is just only 11.1V lipo one.( And he has not realized it. :()

2 power systems should be the usb side and the M_VIN side.
5 AA batteries maybe can't afford enough power supply.
But 7.4V 2200mAh should do well to drive the them together. Grey.CC

2014-02-27 21:46:46 Thanks once again for the answer. Ok I got it for the 1st solution with 1 power source.
So [u]why do DFRobot introduced in the Romeo v2 R3 the possibility of the two power systems to be separated with an on-board switch[/u]?

I found the project of this guy :
[url=http://battle-bot.blogspot.com/2013/12/braitenbot-2-fear-and-aggression.html]http://battle-bot.blogspot.com/2013/12/braitenbot-2-fear-and-aggression.html[/url]

He separated the 2 power systems, explaining this problem with only 1 power system :
"However, once the batteries weren't so fresh, a sudden change of direction on the motors would result in enough of a drain on the batteries to cause a voltage drop that would reset the Arduino"

If there is a switch it means I can do it, right?. [u]But where please should I plug the power for the microcontroller?[/u]
This guy use a Lipo 11.1v which seems extremely high regarding to the classical 5V input for Arduino.

Thanks in advance.

Antonio Antonio

2014-02-27 11:14:53 Hello Antonio,
No, one power is enough.
The Romeo V2 has a power convert chip.
So it only need one power supply, if you are going to use the Pirate.
7.4v has been O.K.(Link above)
Connect the battery to the M_VIN. (Picture)
It is better to add an female adapter between romeo and battery.
[url=http://www.dfrobot.com/index.php?route=product/product&filter_name=female%20adapter&page=2&product_id=508#.Uw6tp_lyDFI]http://www.dfrobot.com/index.php?route=product/product&filter_name=female%20adapter&page=2&product_id=508#.Uw6tp_lyDFI[/url]

Grey.CC

2014-02-27 04:21:39 Thanks for the reply. But I dont get your answer. I wrote that the best solution seems to use the switch to separate the power between the microcontroller the motors and use 2 power source. Do you confirm?

If yes, where should I plug the power for the microcontroller and with which kind of battery (Voltage)?

Thank you in advance.
Antonio

Antonio

2014-02-26 11:06:05 Exactly!
So the romeo V2 has a M_VIN power interface.
When you connect a battery to this port. A part of power will drive the motor. The rest will be translated to 5V to support microchip.

The voltage of the battery depends on your demand,
For 4WD Pirate, I think this should be O.K.
[url=http://www.dfrobot.com/index.php?route=product/product&filter_name=battery&product_id=489#.Uw1ZIPlyDFI]http://www.dfrobot.com/index.php?route=product/product&filter_name=battery&product_id=489#.Uw1ZIPlyDFI[/url]
For romeo V2, it is better to add an female adapter to connect battery.

Grey.CC

2014-02-26 01:06:49 Hello,

I looked everywhere on internet, in every documentation I found but I can't understand clearly how to power the Romeo v2 in an efficient way with the 4WD platform Pirate. What is the best way to do it?

My proposition :
- using Romeo v2 in the switched power mode (for avoiding to reduce the amperage and that the microcontroller restart all the time when the battery is low) :
- 1 power source for the microcontroller
- what ideal voltage?
- where to connect it on the Romeo (the 9V plug disappeared on the V2, I understood I could connect it to the micro USB, or directly to the 5V/GND pin at the condition that I have exactly 5V power source)
- which type for the ideal batteries (lipo, nimh,..)
- 1 power source for the motors (regarding the Pirate 4WD it is 4 motors: 3-12V DC with stall current(6V):470mA)
- what ideal voltage?
- where to connect, it is abvious, in the "Motor Power In"
- which type for the ideal batteries (lipo, nimh,..)

Other question :
- Lipo batteries seems the good solution regarding all the comments I read because it is light and powerfull. Do you know what kind of charger should be used for it?

Thanks a lot!
Antonio Antonio