Sunday, October 28, 2012

Arduino Halloween

Had fun with the kids yesterday preparing for Halloween

1 pumpkin
1 recycled Happy Meal toy (I think)
1 Arduino Duemilanove
1 distance sensor
3 yellow LEDs
3 red LEDs
2 blue LEDs
1 9V battery
1 300 Ohm resistor

Tuesday, October 9, 2012

I love hacker friendly toys

My old Nabaztag was the first victim.  This time it's the turn of a Nerf Blaster clone:
After removing some standard Phillips screws, I got exactly what I wanted:
  • The orange "launch" module in the bottom left of the picture. It's a standalone piece that's originally powered by 3 AA batteries but should work fine on a Arduino friendly 5V (or higher :-). Even the mounts can be recycled for the project I'm working on.
  • The orange "piston" at the top of the picture. I had a simpler design in mind but this one is more compact so it will work even better.

I bought this toy in a local store but I usually go to the flea market in Cormano where I can pick up a R/C car / toy without remote control for a few euros. Way cheaper than buying individual components like wheels, engines, and electrical components piece by pice.

Photos / video of the final project should be available "soon".

Monday, August 13, 2012

How to configure WiFi connection on a HP F4580

Just a note to myself as I wasted more time than I should have fixing this.

I recently changed the WiFi access credentials and my HP F4580, obviously, stopped working. Neither the Mac nor the Windows drivers I had let me edit the WiFi settings but I finally found a way to reset the WiFi configuration:

  • Turn on the printer
  • Click and hold down the Cancel button
  • Click and release the WiFi button
  • Release the Cancel button
This creates a ad hoc network called hpsetup that you can connect to via WiFi to configure the router.

Friday, March 9, 2012

Android table rover

This guy is the reason is the reason I haven't gotten any more work done on my Android powered rabbit.

I started off using 3 MaxBotix MB1000 sensors (downwards left, forward, downwards right). The forward sensor always worked pretty well but I had problems getting fast and accurate readings from the sensors pointing downwards. Without calibrating the sensors (making sure they were pointed away from any object) I got results that where to inaccurate to use for table top navigation.

Tonight  I tried the Sharp GP2Y0D810 sensor from hobbytronics which makes a huge difference. It's lightning fast and it has a small red LED which is lit when there is an object within a 2-10 cm range which is a great help for debugging. The sensor may be less versatile then the MaxBotix sensor as it only gives a true/false result for a limited range but, in my experience, it's fast, accurate and developer friendly which I exactly what I need. It also cost a lot less :-)

The rover in the video is using two Sharp GP2Y0D810 sensors pointing downwards and a MaxBotix MB1000 for obstacle detection.

Wednesday, February 15, 2012

ICSI Netalyzr comparison of SiADSL and Tiscali

I'm in the process of migrating from SiADSL to Tiscali for my home ADSL connection. I have been very happy with SiADSL but I need more bandwidth in upload for video conferences, i.e. Google+ Hangouts with extras. The increase from 7Mb/512kb to 20Mb/1Mb should make a significant difference.

I heard from Michele that Tiscali blocks some ports so I wanted to have a record of the differences between the two provider in case I had problems. Netalyzr to the rescue! It can run as a Java Applet or as a command line client for the more security conscious. It takes several minutes to run and tests everything I ever knew about and then some...

So, what changes between Tiscali and SiADSL?

Tiscali blocks some TCP and UDP ports which I consider a feature, not a problem, if you have Windows machines on the network:

  • Direct TCP access to remote RPC servers (port 135) is blocked. This is probably for security reasons, as this protocol is generally not designed for use outside the local network.
  • Direct UDP access to remote NetBIOS NS servers (port 137) is blocked.
  • Direct UDP access to remote IKE key exchange servers (port 500) is blocked.

I was surprised to notice this potential problem though after I moved to Tiscali:

I passed from PPPoE which uses a max MTU of 1492 to PPPoA which supports 1500 and I had forgotten to update the max MTU on my border router. I tried to leave the max MTU at 1492 but quickly had problems so I increased it to 1500 and it has been working like a charm since. I would have blamed my connectivity problems at Tiscali unless Netalyzr found the problem for me.

I'm also pleased to see that this warning I had on the SiADSL connection is gone with Tiscali:

Exactly the behavior I have seen over the last year(s). Uploads with Picasa killed internet access and video conferencing with many participants is "impossible" even with no other traffic.

Wednesday, January 25, 2012

Finally an anti fog solution for helmets and glasses that works!

I use my motorcycle every single day of the year as long as the roads are not icy which is 360+ days a year in Milan :-)

The only problem I have is that my helmet and glasses fog up when it get's very foggy or cold. I have tried everything, but so far the only thing that has worked is keeping the visor up.  Not fun when it's below zero...

EICMA changed that when I found the stand. I got a sample of their helmet anti fog product which worked very well on my glasses so I ordered a set of their long lasting anti-fog treatment. It worked perfectly today on my helmet visor and glasses. I don't know if it will last the advertised two weeks, but I'm very happy so far.

It really does work as well as the demo video shows: