[ros-users] [Discourse.ros.org] [ROS Projects] Tractobots, my attempts at field robots

[Lasse Einig]

We have a need for a kill switch as well, and found that the only suitable wireless kill switches start close to 1000. Thus we also decided to build our own kill switch (using heartbeat and an active kill signal for below reasons). We also ordered Featherboards and will use an 868MHz signal. We calculated (most pessimistic assessment, heart beat at 100Hz) that our 2200mAh battery will last at least 10 hours. Judging from your picture I would assume that you have a larger battery, you should have no problem sending a heart beat signal for the whole day at 10Hz.

Yes it is a different category, but the run-stop of our PR2 runs for about a year on 4 AA-cells. It's a bit clumsy, but I would never trade more battery time for security, especially when running a tractor.

We plan to put code, parts list and 3D-printable model on thingiverse or an open git repo once our student is done building it.

Heartbeat: obviously required in case the battery runs out or the signal is out of range
Active Kill Signal: in case someone duplicates the heart beat signal, the active kill signal blocks the Heartbeat. Reset switch will be placed on the receiver. This way, multiple kill switches can be used for a single receiver, as well as multiple receivers for one kill switch (signal will have an ID to avoid interfering with multiple setups)






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