Still here...

 but no new tests.

I've got some stuff running in the lab on a Raspberry Pi, but it's not relevant to this blog.  On the other hand, it's very useful to me.

Test done

Okay, so I stopped the scintillator test a while ago.  It's pretty apparent that the frequency of positive signals is much higher with higher temperatures, so there's a thermal effect going on that likely swamps any muon scintillator signal, if any.  At this point, I can't tell whether the thermal effect is in the electronics or if there's some sort of thermal-fluorescence in the scintillator that is being picked up by the light sensor.  Maybe I'll figure out how to test which it is some time later.

The full data set

Reload to update.

By the way:  The effing European Union bureaucrats require you to be warned, if you're from the EU, that this site may use cookies.  Well, I don't put in or collect cookies and don't give a damn, but maybe Blogger.com does.  If they do, then I don't know about it.  Maybe the analytics that Blogger.com collects and makes available have something to do with it.  Damned if I know.  If you're from the EU, Google/Blogger will put up a warning automatically.  I don't do anything to obscure it.  Consider yourself warned.

Some Arduino Sensor and Python work.

Live plotting from DropBox Public.  Press Reload to update -- the figure is updated every ~10 minutes.

Explanation:  I have a little scintillator experiment set up in a light-sealed box.  The luminosity comes from an Adafruit High Dynamic Range sensor attached to an Arduino Uno and timed via Arduino code at 600 ms for ultra-low light sensitivity.  The sensor is facing some fragments of PEN plastic, which is known to be a pretty good scintillator.  No, I don't expect to see scintillation from secondary atmospheric cosmic rays, given the sensitivity and timing, but you never know -- I may get a shower.

The temperature and humidity come from a DHT11 sensor purchased from Amazon.com.  Just in case I pick up electronic noise in the light sensor due to thermal variations, I'll know if the temperature changed.  So far, no.

The Arduino is set to read data as often as possible, given the 600 ms integration time, and the plot to the local screen.  So, about once a second.  Data are saved to a file once every 61 seconds (I suppose I should fix it to 60), unless the reading shows a change in luminosity, in which case the change is registered immediately to disk.  The image is update on the web every ~10 minutes, and approximately 3600 readings are plotted (i.e. up to an hour).

328eForth

Just checking in:  offete.com seems to be a defunct website now.  However, 328eForth seems to have more than one iteration on GitHub, so it still exists.

Oh, yes, and a big middle finger to the European Union for its laws about this or that nonsense.  I don't use cookies on this website, and if Google does, that's their business.  However, I don't like European bureaucrats telling me what I have to do.  I'm an American, and proud to be so.  So, Eurocrats, Bite Me.

Burned out Arduino recovered

This doesn't have anything to do with the RaPiArbot, but a few weeks ago, I was asked to look into putting FORTH on an Arduino Uno.  It was for a project at work.

I was able to get a working implementation of 328eForth on it by using one Arduino to program another. (www.offete.com has been reorganized, so I'm not sure where to get the 328eForth image any more.  I think you can e-mail them.)

I had tried using a USBtinyISP AVR Programmer to write the Arduino, but in the end it turned out to be easier just to hook up one Arduino as a programmer for another Arduino.

In order to make sure it was working safely, I also reprogrammed the bootloader of the Arduino with Forth back to the original Arduino bootloader.  I wanted to be able to recover my own Arduino after I was done playing with Forth, and I was successful at restoring the Arduino.

Then, on a whim, I tried restoring the bootloader on the Arduino that had been burned out, and it ended up working again.

So... nice.

Arduino restored, robot demoed at the hobby store

I got the Arduino board replacement on Wednesday, and everything worked out fine.  I can't tell if the ultrasonic range finder burned out a little or if it is just as crappy as it always was.  I won't bother replacing it, though.

It turns out that the new rubber tires I got from the hobby store are a little too grippy.  Because the tires require at least a little slippage when the robot turns (rotates), the robot can't turn at all because the tires simply don't slip on our floor.

So, last night, I decided to return to the hobby store to see if I could buy a different set of tires that maybe had better traction than the original tires but less traction than the ones I bought on Monday.  I also decided to bring in the robot, along with my old Airport Extreme Base Station and MacBook Pro, so I could give a demonstration.

I got there just before closing, which was at 7 PM.  A few customers came by to ooh and ah at the robot on the counter and ask questions, but extremely embarrassingly, I couldn't get the robot to run because I couldn't get it to connect to my base station.  My MacBook Pro was able to connect, and it could see that there were about a dozen other WiFi stations in the immediate area, so it must have been interference that was causing the Edimax WiFi dongle on the Raspberry Pi to have problems.

Then, right at closing time at 7 PM, the Raspberry Pi finally made contact.  I think the nearby Makerspace shop must have closed up and shut down its own WiFi access points, cutting down on interference.  There were only the three store staff people left in the store, but I was able to run the robot around a bit and show them how it worked.  I was also able to show them how the original tires slipped on the floor, so the guy who specialized in RC race cars was able to find a pair of racing tires that were softer than the original tires but harder than the tires he sold me earlier in the week.

I think the new tires will do nicely, but I also think that the best thing will be to switch tires depending on the surface the robot will drive on.