I am interested in creating a group of robots that can move together outdoors while being aware of each other's locations. I have considered using a "main" robot and a network like NRF24L01, but I'm concerned that if something happens to the main robot, the others will stop functioning. Is there a better solution for this? I need to transmit 100 bytes per second to every robot with the necessary information, and it should work reliably outside. Additionally, I need the system to handle cases where multiple robots (2 or 3) want to send data simultaneously.
Could you please help me with finding a suitable communication method or solution that meets these requirements?
what is the maximum distance between robots?
consider LoRa point to point
to avoid multiple robots transmitting simultaneously consider the master polling the slaves
what host microcontroller are you planning to use?
How far you want the comms to work is a key requirement. 'Outside' could be 10m or 10km.
Whilst an NRF24L01would have no problem sending data at a rate of 100 bytes a second, the size of a single packet is maximum 32 bytes. So you would need to send multiple packets for that 100 bytes.
LoRa devices have a max packet size of 255 bytes, so the 100 bytes can be sent as one packet.
Not possible, unless the robots are on different frequncy channels a long way apart in frequency.
What is possible is to send the data to the 3 robots straight after each other but do it quickly.
The max. distance between the robots is going to be in meters, it's just an experiment, let's say 15 meters max. To control the robots, I'm going to make custom PCB with rather STM32F10... or Atmega328P (basically Arduino Nano), but I will propably go with Atmega328P considering it's just a prototype. I will definitely look for what you suggested to me.
what is the envionment? any obstacles? e.g. walls, trees, etc
you could consider WiFi if the micros had a good antenna
have a look at the ESP32 which has built in WiFi (and Bluetooth classic and BLE) which saves interconnecting seperate modules which is always a problem
have a look at ESP-MESH
I looked up ESP-mesh and it's pretty awesome, but I am worried about the distance, meaning how stable would it be. That will definitely take some more research, I have one more question, when using ESP-mesh the nodes doesn't require internet connection, correct me if I am wrong. Thanks
correct - it is just a local network - internet not required
it would be worth experimenting with a couple of nodes to see how far they could communicate
Outdoor robots can use a GPS receiver to synchronize their clocks to within a fraction of a second thus allowing the creation of a TDMA system where each robot is assigned a specific time window during which they are allowed to transmit.
All robots with GPS reception can leave and rejoin the system at will. There is no need for a 'main' robot or other single point of failure.
15m is no problem for WIFI.
You could let send each robot its position via UDP broadcast.
however I'm more concerned regarding the accuracy of you positioning system. How will you determine the position on each robot?
Interesting..
Going to be doing something similar..
Would also recommend ESP32..
WiFi can be extended outdoors quite easily..
Use a central server, all bots connect..
Still have allot to work out, but my server is up..
unfortunately, have to move in the next month, going to slow me down some..
