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Showing posts from October, 2014

FLL EV3 Robot

This blog post is about our current EV3 robot we're planning to use in the 2023/2024 FLL competition. Some features: 2 large motors for steering. 2 medium motors for attachments.  2 colour sensors for picking up the white and black lines, also used for line squaring. 1 gyro sensor. To enable attachments to be changed as quickly as possible we're using gravity to keep the gears connected, i.e. you don't need to fasten anything to the robot. Every attachment has 2x 12 tooth double bevel gear (part 32270) which comes in contact with the 2x 20 tooth double bevel gears (part 32269) on the robot. The medium motors are horizontally aligned on the robots, but we use 12 tooth double bevel gears to convert that to vertical alignments. These in turn are connected to 20 tooth double bevel gears, and the attachments in turn connect to these 20 tooth double bevel gears with their 12 tooth double bevel gears.  The complete robot is modelled in Bricklink Studio 2 . You can download the rob

Network simulator: DummyNet on Hyper-V

DummyNet allows us to shape a network (latency, upload & download speeds). It runs on FreeBSD. In this example Hyper-V will be used to create a VM that acts as a bridge between two networks (switches). Based on http://www.packetu.com/2014/01/01/building-bad-network-dummynet/ and adapted for Hyper-V. Create new private switch You also need to create a new private switch. The idea is that DummyNet will be installed between a server and your normal network (switch). So instead of connecting the server to your normal switch, connect it to the private switch. DummyNet will act as a bridge between the private switch & normal switch, meaning traffic on one network will be replicated to the other network and vice versa, plus it will shape the traffic. Install FreeBSD Download FreeBSD 10. You only need the CD ISO as we’ll install a bare system. Create a new VM called DummyNet with 128 Mb RAM, 2GB harddisk and