Yesterday, Jill and I were able to successfully integrate the mesh network with three of her paper cars. We were testing the ability to send instructions to multiple vehicles over the network. Since our 433 MHz packet radios in tests would send messages within three milliseconds and the painlessMesh library would send messages over Wifi within about 50-100 milliseconds at the worst, we suspected that an instruction that one car would propagate to all other cars would be executed by all cars virtually simultaneously. During our integrated demo, each car will be passed a different instruction; however, for this test, we just used the joystick on the dashboard to control all the cars.

The way the joystick control works is that one of the cars (the white one) is connected to the dashboard and receives the joystick input. Then, it sends that joystick input to all of the other cars on the network over both Wifi and the 433 MHz packet radios before executing it itself. Here is a video of when we tested three of the cars in the same network:

As you can see, for the majority of the different types of movements, all the cars begin to move at almost the same time, which is especially visible when the cars stop. There are a few times where one car has a bit of delay. Furthermore, another thing you may have noticed is that each car reacts differently to the same instruction. The reason for this is because of slight differences in the motors, wheels, weight, and center of masses of the cars; for example, the white car has a phone power bank powering its ESP32 feather board instead of a LiPo, which adds more weight. This won’t be an issue during the demo since we don’t need the cars to be synchronized, as well as the fact that each car is going to be getting its own individualized instructions.

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