I’m having a problem with my Rover V2 autonomous (RB-Rbo-138) – it works fine when connected on USB, but as soon as I put it on battery power, it drops dead. I thought it might be an issue with the LiPo battery, so I switched to the 4xAA battery pack (with fresh batteries), removed the jumper, but it still won’t run, it won’t even light up the LEDs. I am only seeing about 1V on the 5V pins. I don’t quite know what to do at this point, any help would be appreciated.
Yes, I’ve got a multimeter, here is what I am seeing: I’m using 4xAA, I have 5.9V at the JST connector (with the switch off), it drops a bit to 5.7V with the switch on. USB is disconnected at this point.
Plugging in the USB, then testing the 5V points on the prototyping area and VCC on the expansion board I’ve got 4.5 V with the USB plugged in and switch on, 4.3 volts when I turn the switch off with USB plugged in. That is what’s expected I think.
I then turn the switch back on, then unplug the USB so I’m just on the battery, now I’ve got 3.7V at the 5V points. The LEDs are lit, but it looks like the voltage is a bit low.
Then I turn the switch off, I get 0 V at the 5V points-- I’m not sure that’s right, it should still be supplying voltage to the board I think, with just the battery plugged in.
If I then turn the switch on I only get 1 V at the 5V points. Again, this is just on battery, obviously won’t run or even light the LEDs. This is making me think there is something in the hardware – I can only guess the voltage regulator is not supplying the proper voltage?
The part that is very strange is that the sequence matters – if I leave the motor switch on and unplug the USB, I get some power just from battery – not all I need but it lights the LEDs and will run a little bit using the AAs. But if I turn the motor switch off, unplug the USB, switch it back on again I get basically nothing.
OK, here are a couple, I have the pan/tilt servos and ultrasonic sensor on, and currently unplugged the LiPo and plugged in the 4xAA. I have the servos on pins 2&3, and ultrasonic is on pin 9.
The power switch does not work well either with LiPo or 4xAA – if I unplug from USB and turn the switch off then on again, it does not work, won’t even light the LEDs.
If I have the motor switch on, then unplug from USB and leave it on, it works somewhat. The 4xAA will at least run the motor and board, but not motor+board+ping sensor. The LiPo sometimes runs the motors, but is inconsistent.
I have been very careful about the jumper.
I guess at this point I’m trying to figure out some workaround so my $200 autonomous rover will be able to rove farther than the end of the USB cable. I am not sure but I think it might be possible to get another 4xAApack, cannibalize a mini usb cable to wire the 4xAA with a 5V voltage regulator and plug it in to the mini USB, maybe that will help.
If I turn the switch off, then on again while disconnected from USB it won’t turn on, will not even light the LEDs.
This is the head scratcher. Does the power switch work well when only a LiPo battery is connected? Is the issue really only with the AA pack? If so, it sounds like the AA pack cannot provide enough current to run it all with the code you created, and you may need a more powerful LiPo pack (ex. 2mAh, or even 7.4V, 2mAh+). Note that the onboard LiPo charger can only charge 3.7V LiPo batteries. When you use the AA pack, you are certain to remove the LiPo jumper in the left rear of the board?
Send us a ticket via the support center -> returns & exchanges department and link to this thread.
First step is to certainly check the wiring. Try just the bare rover without the shield or anything else connected and see if you can control it via USB cable using the WASD sample code. If you don’t encounter any issues, then plug something else in and repeat. Note that the servos used on the Pan/Tilt can consume up to 1A each (250mA nominal) and using these at the same time as the drive motors means the batteries have to be able to provide about 3-4A. Normally an Alkaline battery can only provide 1C discharge, while an NiMh battery (rechargeable) can provide up to 2C. Hope this gives you some ideas.
Do you have access to a multimeter? If so, can you check the voltage at the battery terminal (small white JST connector) when you have only the battery pack plugged in? Tell us the voltage it reads. We do apologize for any inconvenience and hope to resolve the issue ASAP.
Can you post an image or two of your setup?
I disconnected the expansion shield, so all I have is motors, and run a forward, reverse, right turn sketch. It worked fine on USB. I left the motor switch on, unplugged USB, and hit the reset button and it ran OK on batteries. If I turn the switch off, then on again while disconnected from USB it won’t turn on, will not even light the LEDs.
I plugged the expansion shield back in, and plugged in the ping sensor, not the servos. I ran the forward/reverse/right turn sketch again. It runs fine on USB, will not run consistently on LiPo, but will run on 4xAA.
Now I add the ping sensor, and run a sketch where it runs forward until it gets within 6" of an object then stops. It runs fine on USB, and will not run on LiPo or 4xAA. Trying to run on 4xAA the red light blinks is all that seems to happen.
So, I am guessing either the voltage regulator is defective, or maybe there is not enough power to run the board with motors+ping sensor?