Saturday, 13 May 2017

Raspberry Pi User Group Meeting, April 30, 2017

We had somebody new come in to see what we had to offer Sunday afternoon on April 30th. Our guest had a 3.5 inch touchscreen purchased from eBay that he wanted running. We had not done this before ourselves but were quite comfortable looking up different sites for specific resources and tutorials. We quickly found something that almost had all the functionality working. We could not get all the capabilities working for the touchscreen but it worked with a keyboard and mouse. Given a little more time and knowledge we could have figured out the specific problem with this particular distribution of Raspbian.

The rest of the afternoon was spent working through a couple of tutorials of programming an Arduino with a Raspberry Pi Zero Wireless and serial communications via USB cable. What a great little system it is that allows such a small computer to program and operate an Arduino. The RPi Zero Wireless has a processor about equivalent to the original RPi Model B and 512MB of RAM in a size less than half an RPi 3, Model B. The intended use of this type of setup is to run a motorized robot with a good amount of computing power with the stable motor driving and miscellaneous electronics peripheral capabilities. For instance, servo motors are more stable using an Arduino compared to an RPi. Keep coming back and you will see something develop.

If you have not checked us out on, we meet about once per month on a Sunday at the New Glasgow Library. We are usually listed in their events which can be found here:

Our next meeting is May 28th, 2 - 5 pm.

If you are interested in us, make sure you look up the correct library. We meet in the Community Room at the New Glasgow Library. There is also a Raspberry Pi, Model B, available for anybody to come in a use on request. I recommend a little reading about it before you use it. This goes for all people who have not really used a DIY electronic device with any number of electronics pins (aka in electronics as GPIO) used to connect things like LED's and pushbuttons.

V = IR is a good equation to know how to work.

Basically, if you connect an LED to a pin, make sure to use a resistor of at least 100 ohms. If you neglect to use a resistor or use a resistor of too low a resistance, you will permanently lose use of that pin or sometimes worse. Do a websearch on the subject and you should find lots of tutorials. Check out the blog post here for a specific application:

The great news is that you can still use the Raspberry Pi with very little electronics knowledge just as a computer. It does all the major things that a computer will do such as listing files and directories, making files, editing files, changing file permissions, working with shell scripts and the like.

A great resource is The Magpi, the Raspberry Pi magazine which can be found on the Raspberry Pi website. You will find lots of reading material and projects in this magazine. It also has a great and growing collection of small PDF's on essential subjects that help in the process of getting to know the Raspberry Pi, including one on the DIY electronics.

The link below will get you to the RPi site. Have a look around - it is worth it to find out about the RPi.

If you are uncomfortable with plugging things into the Raspberry Pi but still feel the desire to make something turn on and off, try looking up a video on the subject. It will help immensely. You can find a large number of videos on how to connect things safely, though not necessarily having safety in the title. A little knowledge goes a long way. At the same time, use common sense. An LED is a great device to learn how to use. First try using an LED, a 9V battery (no higher), a current limiting resistor, and necessary jumper wires.

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