Editing Known Issues

In our work and during the course a number of issues have come up ... and for some of them, there are also solutions.

= PWM Output (for Servos) =

Re-execution (basically executing a script more than once, without rebooting in between) may not work.
PWM output will not switch off.

the workaround is to always deinit the PWM before using it, e.g.

<syntaxhighlight lang="python" line='line'>
servoPin = Pin(27, Pin.OUT)
pwm = PWM(servoPin, freq=50)
pwm.deinit()
pwm = PWM(servoPin, freq=50)
</syntaxhighlight>

= Servos =

== Servos and Power ==
Servos and motors are power-hungry and many of them will also require a higher voltage. A sign of the servo not having enough power is, that it does not move smoothly or that it only jitters.

Servos have in general 3 connections: GND, VCC/+, and PWM (the control pin). 

A typical way to connect it is to connect PWM to the ESP32/ESP8266 (and to a PWM output pin). The GND is also connected to the ESP. VCC/+ is connected to the power supply, in the most simple case the 5V Pin of the ESP32/ESP3266 - this is connected to the 5V of the USB Port (and limited to 500mA with a fuse).

If you need more power you can use an external power supply, here it is important to connect 0V/-/GND to GND of the ESP and the VCC/+ of the supply to the VCC/+ of the servo.


== Black Servo ES08MA II ==
The power (current and voltage) of many USB Ports connected to the ESP32/ESP8266 is not enough for the Servo ES08MA. It many cases it will not work.

Workaround: use the servo SG90.
@@ Line 9: / Line 9: @@
 <syntaxhighlight lang="python" line='line'>
-servoPin = Pin(26, Pin.OUT)
+servoPin = Pin(27, Pin.OUT)
 pwm = PWM(servoPin, freq=50)
 pwm.deinit()
@@ Line 26: / Line 26: @@
 If you need more power you can use an external power supply, here it is important to connect 0V/-/GND to GND of the ESP and the VCC/+ of the supply to the VCC/+ of the servo.
-[[File:Servo-ex.PNG|300px]]
 == Black Servo ES08MA II ==
 The power (current and voltage) of many USB Ports connected to the ESP32/ESP8266 is not enough for the Servo ES08MA. It many cases it will not work.
-[[File:Es08maII-servo.PNG|300px]]
 Workaround: use the servo SG90.
-= ESP32 lableing =
-It seems there is a false marking on the additional labels that come in the box. On the left side the additional label says 5V - but the associated pin is actually 3.3V
-[[File:ESP32labels.jpg|500px]]
-= RGB LEDs =
-There are two types of RGB LEDs.
-There is the standard RGB LEDs (this is included in the LMUBox) - which is basically only 3 LEDs in parallel in one housing, see: https://www.sketching-with-hardware.org/wiki/RGB_LED
-There are also "intelligent" RGB LEDs and the are controlled like the NeoPixel Ring (or the WS2812 chip): https://www.sketching-with-hardware.org/wiki/LED_Ring_NeoPixel
-= netvar library =
-There are sometimes problem with return values that cannot be parsed - even so the should be OK.
-This may be a problem that occurs in the HTTP Request.
-It would be good to catch this error in the library already.
-"Hi, we are using 4 different Networkvariables: "kanban1_todo","kanban1_progress","kanban1_done" and "kanban1_working". We actually just write some int-values to them ("setNetVar") and also read them ("getNetVar"). The getting-part sometimes triggers the mentioned "ValueError: need more than 1 values to unpack.". Right now we are just catching the error, to avoid a crashing of the code, but it would be interesting to know, why it is triggered. "
-There is also a second error being triggered by some get-requests:
-  Traceback (most recent call last):
-  File "<stdin>", line 1, in <module>
-  File "<string>", line 301, in <module>
-  File "netvars.py", line 59, in getNetVar
-  File "netvars.py", line 25, in http_get
-  OSError: [Errno 113] EHOSTUNREACH"
-If you'd like to use a different port than 80, you'll need to adjust it in the http_get() function. Otherwise you might receive an OSError: -2.