nodemcu-rc

Remote Control using NodeMCU WiFi. Client can be found here.

goal

Have one or two receivers connected to it and send inputs of some buttons to them via own WiFi. Based on this StackExchange post two web servers are used for data transfer. This is realized using UDP multicasts.

learnings

• Using web servers seems a good idea at first, because it is easy to prototype. Letting the RC wait for the client to answer the request blocks the RC for that time, though.

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hardware hints

digital input

• GPIO16 (D0) safe to use.
• GPIO5 (D1) safe to use.
• GPIO4 (D2) safe to use.
• GPIO14 (D5) safe to use.
• GPIO12 (D6) safe to use.
• GPIO13 (D7) safe to use.
• GPIO0 (D3) and GPIO2 (D4) are safe if HIGH during boot, use pull-up resistors.
• GPIO15 (D8) is safe if LOW during boot, use a pull-down resistor.
• Also available are GPIO1 (U0TXD) and GPIO3 (U0RXD) if not using serial.

In general, pull resistors shoult be between 10kΩ..100kΩ.

digital output

When connecting LEDs, use at least 470Ω resistors in series to not damage the chip. Charlieplexing is possible with low-current LEDs (~12mA).

analog input

There is only one, A0. 0V will result in a 0, 3.3V will result in a 4096. Higher voltage will kill the chip.