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scott_pdp
Posts: 15
Joined: Thu Apr 30, 2015 1:12 pm
Location: Port-de-Paix, Haiti

Hour of Code week experiences

Thu Dec 07, 2017 10:58 pm

I invited some of our grades that don't have computer classes to do after school Hour of Code activities. Wow! I teach high school and our students have computer classes during their 11th and 12th grade years. My goal is to get students in front of computers starting in middle school, but we're not there yet (think more teachers, more classroom space, more hours in a day). Most of our students don't have electricity at home, so that means no computer. If there is a computer at home, it's a laptop used for the whole family to watch movies on. Today, we started with how to rest our hands on the mouse, left click and click and drag. The experience left me exhausted. It was exciting and frustrating.

Our internet connection worked the whole time, but I think the code.org site was getting hammered. It was pretty slow. Three of my Pi3s overheated. This has never happened to me before. Our computer lab is the only air conditioned room in the building and each device has heatsinks installed. Each time when it happened, the mouse stopped responding, then the red led on the bottom of the mouse went out. Next, the temp warning came on in the upper right corner and then the it locked up completely. Clock stops updating and CPU % is frozen. A reboot returned things to normal (but our hour was about up and the students didn't want to start over).

Can anyone tell me if rendering graphics from a webpage would cause the system to heat up faster than say playing a video?

Anyhow, the point of all this was really to see if anyone else had Hour of Code experiences to share. Chime in!

Scott

ejolson
Posts: 2145
Joined: Tue Mar 18, 2014 11:47 am

Re: Hour of Code week experiences

Fri Dec 08, 2017 5:08 am

scott_pdp wrote:
Thu Dec 07, 2017 10:58 pm
Three of my Pi3s overheated. This has never happened to me before. Our computer lab is the only air conditioned room in the building and each device has heatsinks installed. Each time when it happened, the mouse stopped responding, then the red led on the bottom of the mouse went out. Next, the temp warning came on in the upper right corner and then the it locked up completely. Clock stops updating and CPU % is frozen.
The reliability of the Pi 3B has concerned me since it first came out. It would appear most issues arise from power supply problems rather than overheating. The same activities which generate heat also consume extra current, so it can be difficult to tell whether heat or a voltage drop due to a marginal power supply is the cause of a crash. Are all Pi's using the same type of power supplies?

Aside from replacing a power supply, another fix which may increase stability is underclocking the CPU by a couple hundred megahertz. After underclocking, less current is consumed and less heat produced with the resulting system being much more forgiving to adverse operating conditions.

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scott_pdp
Posts: 15
Joined: Thu Apr 30, 2015 1:12 pm
Location: Port-de-Paix, Haiti

Re: Hour of Code week experiences

Fri Dec 08, 2017 3:47 pm

I hadn't thought of checking the power supply. I will do that. Our lab has 18 Rpi3 in C4Labs' Zebra cases. They are attached to the back of each monitor with a VESA plate. We've had great success with them since they were put into service in August. I have a USB power meter that I can put on one of the devices that didn't have a problem and then I'll switch it over to one of the three that overheated. I would love to find out it is only a power supply problem. The only other hardware issue we have seen is that two of them have no working power or 'busy' LEDs. If you look at the Pi, it looks powered off, but it's still chugging away. Weird.

In the past, I have invited only girls to HoC. This year I also invited boys. Next year I will probably invite boys again, but I think I will do separate sessions for boys and girls. The girls are way more into it without the boys present.

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