# chupo_cro

• chupo_cro commented on gavinkeeley's instructable Servo Tutorial6 months ago

In the first picture under the heading 'Step 5: Check the Circuit' the white wire is at the 6th position from the right, isn't that DIGITAL 5?

• r/R = Ua/Ub - 1 is correct but that does not mean we can calculate r as the percetage of voltage drop - see my reply to micheals. (Ua/Ub - 1) is not the percentage of voltage drop.

How are you calculating the drop percentage? From 4.2 to 4 is -0.2/4.2 = -4.8% From 3.99 to 3.796 is (3.796 - 3.99)/3.99 = -0.0486 -4.86% According to your algorithm 4.7 Ohm * 0.0486 = 0.229 Ohm = 229 mOhm which is wrong. The Internal resistance is simply calculated from: R*(Ua/Ub - 1). If the starting voltage (4.2) is x and the ending voltage (4.0) is y, then voltage drops by (y - x)/x percent. 4.2/4 - 1 would be: 'For how many percent we have to increase the voltage of 4 V to reach 4.2 V?'. So the voltage drop is not 4.2/4 - 1 = 0.05 = 5% but is (4 - 4.2)/4.2 = -0.0476 = -4.8%

r/R = Ua/Ub - 1 is correct but that does not mean we can calculate r as the percetage of voltage drop - see my reply to micheals. (Ua/Ub -1) is not the percentage of voltage drop.

• Set the Upload speed (baud rate) in Arduino IDE > Tools to 115200, press and hold the Flash button on the NodeMCU and then plug the USB cable or press and hold the Flash button and press&release the Reset button while the USB cable has already been plugged. Now you can program the board. ChangeSerial.begin(115200);to:Serial.begin(74880);and choose 74880 baud for the Serial Monitor (drop-down menu in the lower-right corner) so you can see not only the messages sent from the code but even the error&restart info messages sent by ESP8266 itself.If NodeMCU disconnects-reconnects-disconnects-reconnects... from the USB then you can power the board by the phone charger and connect USB to serial adapter to TX/RX pins to see the messages or you can just ignore the Serial port. LoLin bo...

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Set the Upload speed (baud rate) in Arduino IDE > Tools to 115200, press and hold the Flash button on the NodeMCU and then plug the USB cable or press and hold the Flash button and press&release the Reset button while the USB cable has already been plugged. Now you can program the board. ChangeSerial.begin(115200);to:Serial.begin(74880);and choose 74880 baud for the Serial Monitor (drop-down menu in the lower-right corner) so you can see not only the messages sent from the code but even the error&restart info messages sent by ESP8266 itself.If NodeMCU disconnects-reconnects-disconnects-reconnects... from the USB then you can power the board by the phone charger and connect USB to serial adapter to TX/RX pins to see the messages or you can just ignore the Serial port. LoLin boards seem to have disconnect-connect problem when using serial port, I have 2 of them and both have the same problem but sometimes, after 10-15 resets (by pressing the Reset button) they start to work normally.