I have been looking for the cheapest/easiest way to get 100 or so different i/o devices to all talk to a "Master." (Sending temp data, receiving motor information) Since i am looking for a simple solution, I went with the esp8266 ($1.50 - Cheapest MicroPython MCU). Connecting 100 of these devices seems to be a challenge over wifi/ESPNOW. Since they will be 2 feet apart, i figured i can connect them in parallel, hardwired, connecting the Master's TX, to every devices RX, and every devices TX to the masters RX. Can i now send data normally, as if i were sending it using wifi, and receive it as if it were a WIFI signal to every device.
\$\begingroup\$
\$\endgroup\$
10
-
\$\begingroup\$ How will you stop the TX outputs shorting to each other? \$\endgroup\$– Andy akaCommented Dec 2, 2022 at 16:47
-
\$\begingroup\$ @Andyaka Diode. \$\endgroup\$– drew woodCommented Dec 2, 2022 at 16:49
-
\$\begingroup\$ Or i can chain the tx-rx lines, and have each module act as a repeater. \$\endgroup\$– drew woodCommented Dec 2, 2022 at 16:59
-
\$\begingroup\$ UART probably isn't the best way of doing this, if you have so many devices. You could probably make it work, but it wouldn't be very easy. Consider something designed for multi-device buses, like CAN for instance. \$\endgroup\$– HearthCommented Dec 2, 2022 at 17:03
-
1\$\begingroup\$ The frequency capability of the diode is irrelevant. You're confusing the flow of current with the flow of information. Diodes only allow current to flow in one direction, but for the information to flow from a UART's TX to another UART's RX, current needs to flow in both directions. The TX needs to be able to pull the RX high, and it also needs to pull the RX low, in order to be able to successfully send a signal. The diode will only allow one of those to happen (depending on which way around you connect it). \$\endgroup\$– brhansCommented Dec 3, 2022 at 14:44
|
Show 5 more comments
1 Answer
\$\begingroup\$
\$\endgroup\$
0
Having 100 devices 2 feet apart means that 1st to 99th device distance is 200 feet. I would suggest any multidrop (for example, RS-485 or current loop) converter to connect then all together. A current loop would reduce amount of Rx/Tx errors stacking up due to various electromagnetic interference sources.
If wireless feature of is not used at all, esp8266 is OK if higher current consumption is not an issue (typical non-wireless microcontroller is consuming less power typically).
