UltrasonicSensor Service


The UltrasonicSensor is typically used in ranging.  This can be very useful for collision avoidance or proximity notification. MRL's event driven ranging DOES NOT use the Arduino's library pulseIn.  PulseIn is written in a way which will interfere with servos.  So this service should provide the capability of moving servos at the same time as finding range.

SR04 - be careful the SR04 & SR05 have GND VCC flipped !


raspi 2 opencv howto? [SOLVED]

juerg's picture

I have a usb camera attached to my raspi pi.

I can capture an image with
  fswebcam -r 640x480 i1.img

and display it wit
inks2 -g i1.jpg

When I start the mrl OpenCV service I haven't been able to get an image. But there are quite some settings available - what settings should work for me then?

Who I am

olifantenbaer's picture

Hello forum,

I'm the Olifantenbaer and I'm very interested in robotics.
Unforunately, my skills in programming and electronics are very limited, but I'm learning.

My home is located in Germany.

Git Merge - Brave New World

GroG's picture

I already have a backup and did merging the "old school" way - but now I'm trying to do it the git way !
We have 3 branches master API (mine) WebGUI (MaVo's) and I'm trying to merge MaVo's WebGUI branch into mine.  I made a pull request and was pleasantly surpised to the auto-merge and views of the changes (well done Git & GitHub)..  I was excited that only 3 files were in conflict.  I know the changes at the moment I want to keep all the changes on my branch which include 2 modified files & 1 delete

Azul with turning stomach

harland's picture

life is good when you can turn at the waist

Retro-fitting Stepper Motors

Gareth's picture

First experiment proves viability of replacing some of inmoovs Servos with stepper motors.

I am using a Planet Gear (blue-box) in the picture above .....fortunately it just squeezes into the chest cavity.

Its downloadable off  http://www.thingiverse.com/thing:20884

I am still awaiting a Nema 17 stepper motor to drive it (this too I hope will slide into chest cavity)

Analog input on Arduino Micro

Markus's picture


as i understand the Arduino Micro has 12 potential analog input.

i am planning to make a pressure sensitive (skin) on the forearm af Robyn with 12 pressure zones.

i need some help to get the analog input working on Arduino Micro  with MRL.

check out my test sensors



the Arduino Micro

Rest Position Problem

juerg's picture

I have my robot arms shoulder connected to be at the rest position (arms down) at 90 degrees. As I understand MRL uses 0 degrees for the rest position.

Had this question before and got as answer to set the rest position of my shoulders manually to 90 degrees with the command:


This however does not work after a reboot. I have tried to set the rest position at different places in the code but trying to set it before startRightArm throws an error and setting it afterwards only has an effect when I restart the python script.