Errata

Raspberry Pi Cookbook

Errata for Raspberry Pi Cookbook

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The errata list is a list of errors and their corrections that were found after the product was released.

The following errata were submitted by our customers and have not yet been approved or disproved by the author or editor. They solely represent the opinion of the customer.

Color Key: Serious technical mistake Minor technical mistake Language or formatting error Typo Question Note Update

Version Location Description Submitted by Date submitted
There was a typo few paragraphs before "Figure 16-3. A web interface to GPIO" in Chapter 16.

It said -
You must run the program as a superuser, using Python 2:
sudo python ch_13_web_control.py

The correct command should be :
sudo python ch_16_web_control.py

 Ming Su  May 25, 2021 
Printed Page 223
middle

I received feedback for 8.1 Installing OpenCV to use:
$ sudo pip install opencv-contrib-python==4.1.0.25

When I do so, it says that version cannot be found.

Assume that there is a new version and need to know it version number.

Joel Nelson Holyoak  Jul 22, 2021 
Printed Page 223-224
pg 223 Installing packages to run OpenCV, pg 224 top of page

When you install all the packages listed on pg 223 and then try to get Computer Vision going with import cv2 on pg 224 (top), you get a libcblas.so.3 error (it is missing).
I found and installed it but now when I try "importing cv2" I get a "numpy.core.multiarray.failed to import error". I tried upgrading numpy but no change.
Please post working code.
Thank you.

 Anonymous  Oct 06, 2021 
Printed Page 244
Solution -> 4th line

When enabling Raspberry I2C bus, the book text says "You are then prompted to restart." That was not the case with my board, and by looking at some forums I was alone with this issue.
After the selecting enable I2C the bus did not work and there was not a message saying restart is needed. Reboot fixed the issue.

Juha-Pekka Repo  Mar 19, 2021 
Printed Page 444
Before the code example ch_14_oled_clock.py

The book instructs to download and install Adafruit_Python_SSD1306 library. That is OK but in my case not enough. I also needed to install Adafruit_BBIO library. Without that the example didn't work. So the following installation command should be added:

sudo pip3 install Adafruit_BBIO

 Juha-Pekka Repo  Mar 19, 2021 
Printed Page 527
Figure 17-32

For figure 17-32, the Sonoff_3 is misspelled sonoof_3. This does not really change anything, it's very minor.

 Pierre Rochefort  Apr 17, 2021