Blog/20131130 Raspberry covered Pi

From Bjoern Hassler's website
Jump to: navigation, search

More from B's blog:

Some older entries are here.

Raspberry covered Pi - or not as the case may be

One the biggest problems I have had with Raspberry Pi is actually turning it on for the first time. Once it's running, it's easier to trouble shoot. At least there's something to work with.

It took me ages to get my first Raspberry Pi to work. A friend had had more success, and gave me a ready-made SD card, but even after I had gotten it to turn on, it only turned on a few times, and then no more. It turned out that it was a rare issue with the memory card being corrupted, which seems to have gone away with a later version of the OS. Still. It was frustrating.

One of the key issues is probably that I don't have an HDMI capable device. My TV has been broken for a while, and the converter cable from HDMI to VGA doesn't really seem to work, at least not on the VGA devices I have. (It seems that the VGA devices need to be HDMI-via-VGA capable, which I guess means that old VGA monitors won't work? I haven't investigated this fully - feedback would be appreciated.)

However - I eventually got it to work, and my first Pi has been running stably for a while, and that's been great.

Recently I got more and more excited about the Pi, and thought that I should do a bit more with it. Given that it's winter, I always wondered how good my heating controls (with combined timer/thermostat) are at getting the right temperature. Given that there is only one thermostat in a central location, and that the controls on the radiators are manual, how does the temperature varies in different rooms? How cold does get during the day or during the night (when the heating is low)? Ideal for some Pi data logging.

Given that I had managed to get the first Pi working, I thought the second one would be easy. Format SD card with official SD card formatter, write file contents of NOOBS image. Nothing. In principle, everything should work (say, the PSU is of the right rating, I am pressing the right key on the keyboard to switch to composite PAL output, the card is formatted the right way, the image is right). If I plug in an ethernet cable, the Pi does get an IP address from my router, and the network activity lights show some activity (probably some sort of ping).

But - no interaction with the monitor, no interaction with the keyboard, as far as I can tell. I'll play for a little more, testing components bit by bit by exchanging them with my running Raspberry Pi system, and if that doesn't work, I'll use dd to install wheezy rather than NOOBS, and try to ssh into the new Pi. I think that should work.

There's a big HOWEVER though. I've got a lot of stuff about the place, have a running Raspberry Pi system, know how to use dd, ssh etc etc. We've often talked about using Raspberry Pi in an international education context, where you'd have to assume that you need to use what you have, and make up your Pi system from what is available.

It would be really good if the NOOBS image made testing of the components a bit easer. Some suggestions:

  • Many people will have a working set of headphones. Could the Raspberry Pi (when booted into NOOBS) give audio feedback via the audio port? Maybe that would also be useful for users with visual impairments. I could just say "I have booted successfully in NOOBS 3.2."
  • Maybe the existing LEDs could do something to show that it's booted successfully into NOOBs. Like the yellow LED flashes three times repeatedly to show that it's waiting for input. Or shows the stage of the input.
  • If that's not possible, maybe one could make a very simple set of LEDs for the GPIO, that provide some sort of feedback during boot. These LEDs could then be reused for the first GPIO project as well.
  • Finally, maybe the NOOBs image could have an emergency ssh client on it, so that the Pi can be accessed via ssh, and further system installation can happen from there on.

If you're trying to use RPi in an adverse environment, then (based on my experience so far) more feedback during the initial installation would be very helpful.

  • The raspberry pi could annouce it's IP address via audio.

In any case, using dd worked for putting on the wheezy image, and ssh worked fine to log in.

More about the temperature logging here.


2013-11-30 | Leave a comment | Back to blog Share on Twitter Share on Facebook