Kill switch

The kill switch is used to cut power to the motors of the robot. This is used as a safety precaution and it is only mandatory in the Mega Sumo class. When the referee sends the stop command, the power to the motors has to be cut. The robot builder is responsible for adding such a kill switch on the robot through them, however the prebuilt module can supply the signal for activating the kill switch.

Prebuilt module

The prebuilt module takes care of all the communication and it is very easy to implement. The robot only needs to wait for the start pin on the module to go high and then it should start. The module accepts supply voltage (VCC) 3.3 - 5V. The VCC GND Start has a standard of 2.54 mm pitch. The prebuilt module can be ordered from the organizer, having a surcharge, during the online registration.

Modes of operation

The figure below illustrates the modes of operation of the module. To be less sensitive to noise and disturbances, the module will save its current state into a non - volatile memory and if it resets, it will return to the last known state. This means that each match will end with the referee sending the stop command.

Figura 1 anexa

If the LED on the module is “on” before the referee has sent the start command, it means that the module is in the “Started” state. Then, the stop command has to be sent and the robot needs to restart for the module to go back to the “Power ON” state.

To be able to run multiple matches next to each other, each dohyo will have its own unique identifier. The prebuilt module can be re-programmed to listen to a new identifier. This is done by the referee, by sending a special programming command which updates this identifier.

Robots which use sensors that are based on IR technology with a 38Khz transmitter modulation are encouraged to start their sensors after the start signal is received. This is done to minimize the risk of the disturbances.

The Home Mode

The module has an option of usage without the special remote control. On the back of the module there are two large pads- Home and GND. If one of them attaches an 1 Kohm resistance between the two pads, the module will accept signal from a standard TV remote control (the remote control that uses RC-5 coding and was developed by Philips, but there are many other companies that use the same protocol). Sony and Nec have their own protocol and the remote control will not work. The best way to test if the remote control works, is to test it with the module. Pressing the 1 button from the TV remote control will be START and 2 will be STOP.

Explanation of use

You can find detailed information about the usage of the startmodules on:

Recommended design for Kill Switch

How to implement Kill switch circuit using a relay:

How to implement Kill switch circuit using an optocoupler:


For answers to the most common questions regarding the start systems:

How to implement everything by your own

For those who want to implement everything by their own and not use the prebuilt module a guide for this can be found at:
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