electronic circuit simulator

I have messed around with electronics for a long time, but a lot of it is still a mystery. So, I was thrilled to realize that free, online circuit simulators exist. My favourite one is http://www.falstad.com/circuit/ . It gives examples of dozens of circuits, you can modify them, or you can make your own. Better yet, no login required, if you want to save your work it will spit it out as a text file you can import again later. Thanks, Paul Falstad & co, for putting this together and hosting it!

Two computers, one set of speakers

We have two windows computers in our kitchen. For a while now they have been set up so that you have to plug the one you sound in listen tabwant working right now into the external speakers. Today I finally looked into a better way. Turns out there is a free one, or free as long as you already have a male-to-male audio cable.
Plug one PC’s audio out into the second PC’s audio in. On the second PC (Windows 7), go into control panel, sound, recording, pick the plug you used, and click properties. Click the “listen” tab and check “listen to this device”. I had to set the levels way down to 5/100 to not get any distortion and just get a full volume output from the first PC.
No more plugging around!

Mouse wheel fix

The scroll wheel on one of our mice was not working right. The mouse wheel is a disk with slots; light shines through the slots and that is how the computer knows when the mouse wheel turns. I took the mouse apart and there was all sort of dirt stuck in the little slots. Cleaned out, works fine now. Nice to see that not all electronics are only disposable and some things can still be fixed.

 

Mouse wheel with dust bunnies
Mouse wheel with dust bunnies

Blackberry m4a audio files in Audacity software

I use use my Blackberry to record audio in meetings and such. It records as m4a.  I use Audacity to edit audio files.

Audacity doesn’t do M4A natively, and the error it gives just says that it can’t read the file.

Turns out they almost have it built in. I didn’t research the exact IP reason that forces them to do it, but the instructions how to finish setting up Audacity to be able to read your Blackberry sound recordings is here:
http://manual.audacityteam.org/o/man/faq_installation_and_plug_ins.html#ffdown

Rowing Umpire Kit

umpire kitI have been working with Sandi Kirby on a table-top training kit for rowing umpires. We came up with a mat that represents a race course, and a set of boats, course markers and other kit that can be moved around the course to facilitate the discussion of various training scenarios.

We are releasing the design into the public domain so others can make their own. Your local sign shop should be able to print the mat, and a laser cutting service like Ponoko could cut the parts for you.

If you are going to make one of these, drop us a note in the comments, it would be neat to hear if someone finds this useful.

Files are:
– the mat:  course
– the accessories: acrylic

Link to Navigo to go to a specific destination

Winnipeg Transit’s Navigo generally won’t let you enter a destination unless you first enter a “from”. I wanted to be able to add a link to a web site that says “if  you want to come here, you can take the bus, click here”, like this link  which will open the Navigo page with Assentworks pre-populated as an address.

Asked 311/transit, and they explained:

The user needs to include the destination information in the link. The best way to do this is to plan a trip using the desired address as the destination, it can be any trip (random origin and time). From the results page, click ‘Modify Request’ in the sidebar. This takes you back to the trip planning page with pre-filled information. Copy the URL from this page, it will look something like:

http://winnipegtransit.com/en/navigo/submit_destination?authenticity_token=****************************&destinationKey=13&destinationName=Forks+Market+%281+Forks+Market+Road%29&destinationType=monument&method=post&originKey=3911&originName=MTS+Centre+%28300+Portage+Avenue%29&originType=monument&tripDate=0

Delete all the unwanted information from the URL (keep all parameters related to destination [destinationKey, destinationName, destinationType]). Then it will look like:

http://winnipegtransit.com/en/navigo/submit_destination?destinationKey=13&destinationName=Forks+Market+%281+Forks+Market+Road%29&destinationType=monument

Use this URL to link to Navigo.

 

HackRF One, SDR#, WSPR and virtual audio cable

I bought a HackRF One SDR recently. The first thing I wanted to do is to try WSPR, which checks for other WSPR beacons to help monitor propagation paths.

I set this up using the free SDR software SDR# and another software virtual audio cable to connect the two.

That much was easy enough, but I have not had a single connection, running it for a bit over a week. WSPR frequenctly says it’s decoding, but nothing pans out. I am using the antenna that comes with the HackRF, which isn’t great but I hear others have had success with it.

I probably have something set up wrong still. I think I need to use CW mode in SDR# for WSPR but have not actually found confirmation for this anywhere. Since it’s not working it’s likely wrong :-)

Odd braille

 

I audited a few lectures of a course put on by the  Manitoba Centre for Health Policy this fall. It was held in the Apotex Building on the Bannatyne Campus of the University of Manitoba. On the way to class I saw these dots on a glass wall.

IMG_20150916_143618 IMG_20150916_143524

Flipped image for readability of braille saying  "of pharmacy faculty of"
Flipped image for readability of braille saying
“of pharmacy faculty of”

They are Braille, and they read “faculty of pharmacy”. I can’t figure out where they are going with this. The writing isn’t really tactile, beyond the feeling of a vinyl sticker on glass. The writing is WAY bigger than normal braille, the letters are about 8″ tall. Being on a glass wall, it’s backwards from the direction you would enter from. They are about the same height of the ground that braille door signs would usually be, which makes me wonder if this is a tongue in cheek response by someone being forced to put a standardized sign on a glass wall that might look better without it. Or, was it just put there so no one runs into it?

Another possibility is that the pharmacists wanted a memorial of their previous status as a Faculty – they are now College of Pharmacy at the Faculty of Health Sciences.

Does anyone know more about this?