Hello everyone,
I have project to control more than 200 nodes with one master (any Arduino board).
I want to ask what is the best way for this project.
Based on Criteria:
Wireless (RF315, Wifi...)
Wire (RS485, CAN, I2C, ...)
Node is one MCU control 10 led WS2812. My budget for one node is lower than 5$, with external power supply.
I wonder if you could help me with this project.
Many thanks!!!
Ps: with option RS485 I will use this module UART TTL to RS485 Two-way Converter
with CAN, please help me guess one module cheap may be work fine under 100m long of network bus.
You need to tell us how much data needs to be sent by the master and whether it needs to get a response from the slaves.
By "how much data" I mean what length is a message, how many messages must be sent per second and whether a separate messages must be sent to each slave.
Thank for your comment!
My data is one byte address and one byte data, one for check data is correct.
Total is 3 byte. Only master send, nodes never response if master don't request.
Master can be know nodes working or not, latency about <5s => each transmit is 5/200 = 40 times/second => 120byte/second.
I think I should make it work at 9.6kpbs. May be fine!
If you send a 3-byte message 40 times per second then it will take 5 seconds to send messages to all 200 slaves. Have I got that correct?
I certainly don't understand this
How could the master know that the nodes are working if there is no message from node to master?
...R
Yes, you are right
oh, I'm sorry. I'm planning there is one byte ACK response from node.
My calculation is master will poll all nodes in 5s, to check node is alive or dead (lost communication).
Can you help me clarify how many data will be transfer in bus, or my calculation is correct or not?
srnet:
Perhaps describe what the project actually is, it might save the forum a lot of time in the guessing ..............
Thank for your comment!
I have 200 boxes for wine, my customer ask me control led in one box via mobile (wifi & gprs) or a handheld controller. I'm planning to choose the way to connect all nodes, over 200m long.
what is the largest distance from one "node" LED group to the next?
If I do the math: 200 nodes on 100m are roughly each 50cm a node. If your are using WS2812 anyway, you have already your bus. why not just connect your 2000 pixels to that bus? If there is a larger distance between some Groups - just add some dummy Pixels to clean up the signal.
Or at least reduce your nodes. I assume it will be much more efficient to control 10 nodes than 200 nodes.
If you really still need a simple bus for light control, consider DMX - (RS485 based).
