Tag: Robotics
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ros2 controller manager not available – articubot tutorials
Hey everyone,I’m currently working through a great tutorial series on youtube for ROS2. Unfortunately, I ran into a bit of an issue with a race condition in a launch file. The controller managers were timing out before Gazebo was able to launch. The author offers a suggestion to try using OnProcessExit to work around this…
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ROS2 on Parallels unable to be reached by other nodes
Hi everyone, I’ve been messing around with ROS2 on a RaspberryPi and a Mac using Parallels to run Ubuntu. I hit a small snag when trying to get the nodes to communicate. The nodes on the RaspberryPi could not reach the ones being hosted on Ubuntu (Parallels). While I initially assumed that I had messed…
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Gazebo classic material colors not working in Gazebo Ignition
Hi everyone, I’m doing a few tutorials to simulate a lidar based navigation system and I’ve hit a few issues when trying to use Gazebo classic features in Gazebo Ignition. A recent one is that Gazebo Ignition was ignoring the material colours that I’d specified in my urdf. This is an example of what was…
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Gazebo Classic to Gazebo Ignition Diff Drive Conversion
Hi everyone, I’m currently following some ros2 tutorials for simulating a diff drive robot in Gazebo Classic. I’m using Gazebo Ignition and unfortunately the definitions aren’t interchangeable. Just in case anyone else hits the same issue, this is the definition I ended up using instead: The following links were pretty helpful when it came to…
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Spawn entity timeout in Gazebo from Ros2
Hi everyone, I’m currently following a tutorial to simulate a fairly basic lidar robot with ROS2 and Gazebo: https://www.youtube.com/watch?v=laWn7_cj434. Unfortunately, there have been a few updates since the tutorial was created and a number of the commands don’t map 1:1 (no copy and paste). While trying to create a launch file I ran into the…
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libgl error pic id driver null – ros2 turtlesim
Hi everyone, I’m currently following the ros2 turtlesim tutorial with Ubuntu on an M1 Mac with Parallels and Ubuntu. Unfortunately, I hit a ‘device not found’ when trying to start the control node. A bit of Googling revealed that 3D acceleration might not be enabled. To fix this, all you need to do is the…
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Change i2c address of ina219
Hi everyone, I wanted to use ina219 with pca9685 but they shared the same i2c address 0x4: 0. Luckily, there’s a fairly easy fix for this. All we need to do is solder two pins together. We’re going to bridge a0 and this will change our address to 0x41. In order to check these run…
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A4988 Stepper motor RaspberryPi
We’re using a 42shd0034-20B Geetech stepping motor taken from a 3d printer: We’ll be driving it with an A4988 stepper motor controller. You can pick up five packs of these for less than $2 online – definitely worth having a few extras around: The datasheet is available here: https://www.pololu.com/file/download/A4988.pdf?file_id=0J450 The following diagram illustrates what we’ll…
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Using INA219 (GY-219) with the Raspberry Pi
Hi everyone, I’ve just setup an INA219B Voltage/Current sensor on my RaspberryPi. Just thought I’d link the tutorials and libraries I used – there’s a lot of really useful info out there. Install the following library via git: https://github.com/chrisb2/pi_ina219 sudo pip3 install pi-ina219 Follow this tutorial: https://www.rototron.info/raspberry-pi-ina219-tutorial/ Misc Notes Common ground is required Vin –…
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Mini-360 DC-DC Buck Converter – Incorrect Voltage 10v Instead of 5v
Hi everyone, I’ve been playing around with a few DC-DC buck converters similar to these ones: https://www.amazon.com.au/UEB-Power-Converter-Module-Supply/dp/B078CXHWXC/ref=sr_1_fkmr1_1?ie=UTF8&qid=1519030369&sr=8-1-fkmr1&keywords=mini+360+buck+converter I had expected 5v output from my 12v supply but when I hooked it up to a multimeter I found I was getting just over 10v. This would fry pretty much everything in my circuit so I was…
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