Forum >DIY Remote Control Robot Kit - works only with usb plugged
DIY Remote Control Robot Kit - works only with usb plugged
Adam 2013-11-09 06:44:06 6571 Views4 Replies Hello,
I have uploaded to the board a merge of the bluetooth sample code and this from the IR sensor kit:
[url=http://www.dfrobot.com/wiki/index.php?title=IR_Kit(SKU:DFR0107)]http://www.dfrobot.com/wiki/index.php?title=IR_Kit(SKU:DFR0107)[/url]
When the usb cable is connected it works fine: the motors can be controlled by the remote control. (Also 6 1.2 V batteries are in the holder, switch turned on).
However when the usb is unplugged once the motors are running, it is only possible to stop the motors. At very low or very high speeds the motors even stop immediately after the usb is unplugged. This happens even when the board is powered using a DC power supply, not the batteries. Another thing is that when the motors are started, the voltage measured on the M_Vin is 4.5 V regardless of the initial power supply voltage, that is to say the power supply voltage also drops to 4.5 V. Sometimes the board restarts when the motor start button is pressed on the remote.
I have many thoughts on this, some of them are: maybe the supply voltage is faulty since it drops when the motors are running, perhaps the board and the motors have to be powered separately, but how to do it?
By the way, the product description on the site says: DC Supply:USB Powered or External 6V~23V DC but the manual says DC Supply?USB Powered or External 7V~12V. Then again on the board next to M_VIN it says 6-20V.
Do you have any further questions, what additional measurements would be required?
Thank you in advance for any hints!
I have uploaded to the board a merge of the bluetooth sample code and this from the IR sensor kit:
[url=http://www.dfrobot.com/wiki/index.php?title=IR_Kit(SKU:DFR0107)]http://www.dfrobot.com/wiki/index.php?title=IR_Kit(SKU:DFR0107)[/url]
When the usb cable is connected it works fine: the motors can be controlled by the remote control. (Also 6 1.2 V batteries are in the holder, switch turned on).
However when the usb is unplugged once the motors are running, it is only possible to stop the motors. At very low or very high speeds the motors even stop immediately after the usb is unplugged. This happens even when the board is powered using a DC power supply, not the batteries. Another thing is that when the motors are started, the voltage measured on the M_Vin is 4.5 V regardless of the initial power supply voltage, that is to say the power supply voltage also drops to 4.5 V. Sometimes the board restarts when the motor start button is pressed on the remote.
I have many thoughts on this, some of them are: maybe the supply voltage is faulty since it drops when the motors are running, perhaps the board and the motors have to be powered separately, but how to do it?
By the way, the product description on the site says: DC Supply:USB Powered or External 6V~23V DC but the manual says DC Supply?USB Powered or External 7V~12V. Then again on the board next to M_VIN it says 6-20V.
Do you have any further questions, what additional measurements would be required?
Thank you in advance for any hints!
2013-11-12 22:23:44 Using 5x1.5V batteries instead of 5x1.2V worked. Thnak you for the replies. Adam
Adam 2013-11-12 09:03:28 It seems that you don't feed enough current to your robot. When 4 motors are activated at the same time, it draws about 2A current.
So, your conclusion is correct. Give a more powerful battery pack will solve the problem.
R2D2C3PO
So, your conclusion is correct. Give a more powerful battery pack will solve the problem.
R2D2C3PO 2013-11-12 00:14:06 Hello Adam
When the robot works with usb plugged, whether did you open the serial monitor on pc?
And about "restart" I think it is because the code. It need to be optimized. Grey.CC
When the robot works with usb plugged, whether did you open the serial monitor on pc?
And about "restart" I think it is because the code. It need to be optimized.
Grey.CC 2013-11-10 17:29:46 To simplify and report on our advances:
When the board is powered via the battery pack (6V), it restarts every time we try to start the motors with the remote. We found that it works properly only when 1 out of four motors is connected.
We think that when the usb is connected, it keeps the board powered at a constant +5V and the battery voltage drop does not affect it. (But then again when the board was powered through a 12V power supply, it did not restart, but the motors could not start anyway, which baffles us.)
So our ideas are to either use a usbcell or buy additional motor drivers so that there is no voltage drop.
But we also know that there already is a motor driver in the board.
We have also tried to analyse the schematic and figure out where exactly the vusb and m_vin go. Our conclusion is that we need a power supply that never drops below 5V.
What do you think? Adam
When the board is powered via the battery pack (6V), it restarts every time we try to start the motors with the remote. We found that it works properly only when 1 out of four motors is connected.
We think that when the usb is connected, it keeps the board powered at a constant +5V and the battery voltage drop does not affect it. (But then again when the board was powered through a 12V power supply, it did not restart, but the motors could not start anyway, which baffles us.)
So our ideas are to either use a usbcell or buy additional motor drivers so that there is no voltage drop.
But we also know that there already is a motor driver in the board.
We have also tried to analyse the schematic and figure out where exactly the vusb and m_vin go. Our conclusion is that we need a power supply that never drops below 5V.
What do you think?
Adam 