Robot Problems

[vinefreeman]

hi

I've tried going through the forums but am struggling across many levels and a little frustrated now (have spent many hours trying to get this working).

1 - once I had downloaded your img and go this onto my SD card the bot booted up
2 - we would not move forwards and backwards
3- with the pan and tilt servos connected the camera did a jerking movement and stuck with what sounded like the motors constantly running (I couldn't change this via controls on browser) - so have unplugged
4 - so I can login via safari on ipad (chrome doesn't work with camera)
5 - at first I could spin left and right but after a few seconds connection would drop out.
6 - now it only moves a tiny amount left and right - very slow.

I have plugged into the wall and this allows the wifi to stay connected a little longer, but not much else.

It is a raspberry pi 2, with all bits purchased from you guys apart from SD card and Pi board. I have downloaded your image and put this onto an SD card.

Are there any logs I can copy here to get an analysis - it's not really doing much at the moment.

thanks

[Alan]

Hi there,

Welcome to the forums. Although please accept my apologies for the very delayed reply.

It's possible that the symptoms you describe could be due to power issues. What type of batteries are you using to power the robot?

You can get some logs showing what the robot's software is doing by going to 192.168.42.1/logs.html.

Regards

Alan

[vinefreeman]

Hi Alan

Thanks for coming back to me... Here's the output from that page:

DEBUG:tornado.general:sockjs.tornado will use json module
INFO:root:Starting web server...
INFO:root:Read 0XACED 0.38
INFO:root:Expected 0XACED 0.38
INFO:tornado.access:200 GET /logs.html (192.168.42.15) 51.83ms
INFO:tornado.access:304 GET /js/jquery.js (192.168.42.15) 24.08ms
INFO:tornado.access:304 GET /js/sockjs-0.3.min.js (192.168.42.15) 9.09ms
INFO:tornado.access:200 GET /robot_control/info (192.168.42.15) 3.93ms
INFO:tornado.access:304 GET /logs.html (192.168.42.15) 4.30ms
INFO:root:SockJS connection closed
INFO:tornado.access:304 GET /js/sockjs-0.3.min.js (192.168.42.15) 4.56ms
INFO:tornado.access:304 GET /js/jquery.js (192.168.42.15) 4.74ms
INFO:tornado.access:200 GET /robot_control/info (192.168.42.15) 3.50ms
INFO:tornado.access:304 GET /logs.html (192.168.42.15) 4.62ms
INFO:root:SockJS connection closed
INFO:tornado.access:304 GET /js/sockjs-0.3.min.js (192.168.42.15) 5.33ms
INFO:tornado.access:304 GET /js/jquery.js (192.168.42.15) 4.62ms
INFO:tornado.access:200 GET /robot_control/info (192.168.42.15) 3.77ms
INFO:tornado.access:304 GET /logs.html (192.168.42.15) 6.71ms
INFO:root:SockJS connection closed
INFO:tornado.access:304 GET /js/sockjs-0.3.min.js (192.168.42.15) 5.18ms
INFO:tornado.access:304 GET /js/jquery.js (192.168.42.15) 5.16ms
INFO:tornado.access:200 GET /robot_control/info (192.168.42.15) 4.55ms

Batteries: standard duracell. Although I've tried plugged-in to the wall too and head still makes a jerk to the right and sticks...
Although Iv

thanks for your help.

[Alan]

Hi there,

Everything looks good with the logs. The lines that read

INFO:root:Read 0XACED 0.38
INFO:root:Expected 0XACED 0.38

inidcate that the Pi has made contact with the Mini Driver motor control board and that the correct firmware version has been found.

I think that the problem may be down to you using non-rechargeable (Alkaline) AA batteries rather than rechargeable (NiMh) AA batteries. At least I'm assuming that that's what you mean by standard Duracell? The problem with non-rechargeable batteries is that even though they have a higher voltage than rechargeable batteries, they can't provide as much current. This means that the robot can behave erratically or may just run for a short time.

I'd recommend using something like Duracell NiMh 2400mAh batteries, which work really well.

With regards to running the robot off the wall. That's a bit tricky in itself, basically, the wall adapter will power the Pi, but you still need to have batteries plugged into the Mini Driver, and have the power switch turned on in order to give power to the motors. In this case, non-rechargeable batteries will work fine (as it's the Pi that draws most of the current) so this could be a good thing to try to confirm that the rest of the robot works, before you get rechargeable batteries.

Hope that all makes sense. We have a blog post on testing battery life for a couple of different options here.

Regards

Alan

[vinefreeman]

Hi Alan

I didn't disappear! Apologies for not replying - things have been hectic!

I appreciate you coming back and I will try the battery option.

Thanks again.
Vinny

[vinefreeman]

Hi

So I replaced with the batteries you mentioned above, but unfortunately still the same although he spins round a bit faster. I can't get him to move forwards or backwards (using right joystick control via browser). The robot still jerks the camera to the left and up it boots and stays there so I've disconnected that part.

here are the logs:

DEBUG:tornado.general:sockjs.tornado will use json module
INFO:root:Starting web server...
INFO:tornado.access:200 GET / (192.168.42.15) 46.04ms
INFO:tornado.access:304 GET /css/style.css (192.168.42.15) 44.98ms
INFO:tornado.access:304 GET /css/modal.css (192.168.42.15) 6.07ms
INFO:tornado.access:304 GET /js/jquery.joystick.js (192.168.42.15) 5.60ms
INFO:tornado.access:304 GET /js/sockjs-0.3.min.js (192.168.42.15) 6.81ms
INFO:tornado.access:304 GET /js/jquery.js (192.168.42.15) 20.95ms
INFO:tornado.access:304 GET /images/ajax-loader.gif (192.168.42.15) 5.76ms
INFO:tornado.access:200 GET /robot_control/info (192.168.42.15) 2.67ms
INFO:root:Read 0XACED 0.38
INFO:root:Expected 0XACED 0.38
INFO:tornado.access:200 GET / (192.168.42.15) 3.48ms
INFO:root:SockJS connection closed
INFO:tornado.access:304 GET /css/style.css (192.168.42.15) 3.23ms
INFO:tornado.access:304 GET /css/modal.css (192.168.42.15) 3.61ms
INFO:tornado.access:304 GET /js/jquery.js (192.168.42.15) 4.59ms
INFO:tornado.access:304 GET /js/jquery.joystick.js (192.168.42.15) 5.24ms
INFO:tornado.access:304 GET /js/sockjs-0.3.min.js (192.168.42.15) 3.18ms
INFO:tornado.access:304 GET /images/ajax-loader.gif (192.168.42.15) 3.76ms
INFO:tornado.access:200 GET /robot_control/info (192.168.42.15) 2.67ms
INFO:tornado.access:304 GET /logs.html (192.168.42.15) 7.83ms
INFO:tornado.access:304 GET /js/sockjs-0.3.min.js (192.168.42.15) 4.32ms
INFO:tornado.access:304 GET /js/jquery.js (192.168.42.15) 4.37ms
INFO:tornado.access:200 GET /robot_control/info (192.168.42.15) 3.29ms

Does that all make sense?
Should the right joystick work?

Thanks
Vinny

[Alan]

Hi Vinny,

Sorry for the delayed reply on this. I saw it come in, but then completely forgot to reply.

Leaving aside the servo motors for now I think we should look at the wheel motors.

The left joystick is reponsible for making the robot go forwards and backwards, and for turning the robot left and right, the right joystick is just used for moving the pan/tilt neck of the robot.

To test that your wheel motors are working, please make sure that the mini driver switch is set to 'on' and then hold the robot up so that its wheels are off the floor. Then push forward on the left joystick, followed by pushing backwards. This should hopefully confirm that both of the motors are turning in the correct direction. If one is turning in the wrong direction, then reverse the wires connecting it to the mini driver board and try again. Also the left motor should be connected to the pins marked ML on the mini driver and the right motor attached to the MR pins.

Once the wheels are turning in the correct direction, the challenge is to get it to drive in a straight line. This is always a bit challenging as it is very rare for two electric motors to go at the same speed when the same voltage is applied due to manufacturing differences between the motors. One thing that can help to begin with is driving the robot slowly (move the left joystick only a small amount) as then it's much more controllable. Alternatively if you go to the config page (192.168.42.1/config.html) you should see that there is a motor config tab with a slider that lets you set a multplier on the speed of the left motor. You can use this slider to balance the motor speeds somewhat. Move the slider either to the left or right, press the save button in the bottom left corner and then you should see that the left motor is either running a bit faster or slower.

Once the robot is moving slightly straighter we can get the pan/tilt neck to work. I think that one of the servo motors may be shot, so I might have to send you a replacement. Before I do that though, can you please double check the servo motor connections, make sure the GND wire (brown wire) is on the outer edge etc? The right joystick should make the neck move up and down when you push forward/back and make the neck move left and right when you push side to side. Does either of those things work?

Sorry for the fairly epic post, hopefully something here will be of help to you.

Regards

Alan