ClockSkew

What do you do when you can’t sleep at night?  You connect your  bathroom scale to Twitter.  Talk about the ultimate in accountability.  You’ll think twice about eating those brownies before bed knowing you’ll be broadcasting your weight in the morning.

Actually, I had never opened a digital bathroom scale before, so that was the real motivation in doing this.  It’s quite clever.

Scale Innards

A system of levers is used to fractionalize the force before it is applied to the strain gauge bar.  The strain gauge itself is a standard 4-gauge / wheatstone bridge bonded to a bar setup.  The four wires coming from the gauge are the two excitation and two sensor wires.

Strain Gauge Close-up

To interface it with my laptop, I used an Arduino.  The strain gauge sensor only outputs a few mV in difference max under load, and because the Arduino can only pickup changes of about 5 mV (5 V / 1024 ~ 5 mV), I had to amplify the sensor first.  I started to use the classic 3 op-amp instrumentation amplifier until I remembered what a pain it is to find matching resistors.  So, I ended up scrounging up an AD620 from the dead-projects box.  That made the interfacing much easier.

Arduino + Amplifier

Once connected, I calibrated the sensitivity with dumbbells.  (Mental Note: Next time carry the scale to the weights, not the weights to the scale.) I programmed the Arduino to continuously output the raw pin value and then used a 30 lb, 50 lb, 70 lb, and 90 lb dumbbell to calculate the sensitivity.  In my setup (Gain = 150, basically chosen at random.  Higher gain would give me more accuracy), the Arduino is sensitive to about 0.5 lb–acceptable for a bathroom scale reading.  With the sensitivity value, I then programmed the Arduino to return the weight in lbs when queried.

Scale ready to go

To send the weights to Twitter, I used python-twitter.  The python script simply queries the arduino for the weight and twitters it.  Noise is averaged out.  If I really wanted to do this right, I’d daemonize the python script and have it twitter non-zero substantial values, connect wirelessly to the arduino, and power it from the 9V battery in the scale.  But I’m not that serious about it

You can see the Twitter Scale output by following me with the link at the top of page.

After a couple years of stagnation, broken links, and blog neglect, I’m resurrecting ClockSkew.com.  Not sure what I will put on here yet, but I’m often wishing I had a place to put things I think are cool.  So we shall see…

Okay, so I was bored today…

Yesterday an image made the rounds on all the Apple related sites showing a ‘leaked’ image of the new iPod nano. Today most of the larger sites who displayed the image received take-down notices from Apple legal. Consensus seems to be that the take-down notices confirm the image was real. Based on that, it’s possible to approximate the size of the new nano by using an overlay of the current nano and its known dimensions.

I’ve made the assumption that the click-wheel is the same size on both nanos. There is no reason to think otherwise, and in fact they match-up perfectly in width of ring, diameter of center button, font/symbol size, etc.

It’s interesting to note that the distance from the click-wheel to the top of the nanos is exactly the same. Also, the bezel width from the top of the nano to the top of the screen is the same. Using the known dimension of the current iPod nano, I interpolated the size of the new nano to be approximately 3″ x 2.3″ (using the rulers in photoshop adjusted to the pixel/inch scale of the current iPod nano image). That means the length decreased by ~0.5″ and the width increased by ~0.7″.

A size of 3″ x 2.3″ is very peculiar. The 5.5G iPod has a width of 2.4″. Why would Apple make the new nano about as wide as the iPod? The whole point of the nano is that it is significantly smaller than the iPod. With an iPod nano almost the same size of an iPod, indeed with almost exactly the same size screen, there needs to be something else as the distinguishing factor between the two models. That factor could be an iPhone-like touch-screen and size.

Since I’m already taking so many logical leaps (like using a ‘leaked’ image to base all this on), I’ll say the new iPod nano form factor strengthens the rumors that the next iPod will be touch-screen and will be available at the same time as the new nano. This also falls inline with the rumor of OS X on the new iPod. Guess we’ll see.

UPDATE: Yay me!

Just a recap for all those just finding this page and not wanting to slog through all the comments. The following plugins are available at this time.

Motorola RAZR V3m
Motorola RAZR V3xx
Motorola RAZR V6
Motorola SLVR L71/L7e/L7i

All work fine for syncing contacts with the latest version of iSync. Calendar syncing only works on the V3m at this time. I am working on getting calendaring to work on the others. All plugins can be downloaded from the Downloads page.

I got a request for an iSync plugin for a motorola SLVR L71 / L7e / L7i so here it is. As with the other plugins, calendar syncing is sketchy at best. Please drop by the forum and post your calendar syncing errors so I can fix all the calendaring issues.

Enjoy!

SLVRL7-phoneplugin-Ver01.zip

I need someone who uses iCal to test the following plugin for iSync and the V3m. It works fine on my V3m (recurring events, etc.). Anyway, test it and post any bugs in the forum. Once it works fine, I’m add the changes to the other plugins. Thanks.

RAZRV3m-phoneplugin-Ver03-test.zip

Someone asked me to put together an iSync plugin for the RAZR V3xx. Well, here it is. All I need are some testers.

iSync-2.3 RAZR V3xx phoneplugin Ver 4 [16KB]

Put the PhonePlugins folder in either ~/Library or /Library. Enjoy!

Someone asked for a RAZR V6 iSync plugin, so here one is. I don’t have a V6 in my hands, so I had to guess at some crucial details, but hopefully I guessed right.

iSync-2.3 RAZR V6 phoneplugin Ver 7 [32 KB]

Anyway, copy PhonePlugins to ~/Library, test it out, and leave comments of how it fails. Also, the icon I made isn’t the greatest, but it should do. Oh, if you have already paired the phone, redo the pairing after copying the plugin to ~/Library.

I’ve been trying to find a Wii this Christmas and it has been quite difficult. However, I stumbled upon www.OuttaStock.com and it has proved invaluable. I just snagged a Wii bundle using the Nintendo Wii Finder, so I figure I can post my secret now.

Some interesting notes on trying to play music on my phone.

Even though everywhere seems to say the phone only plays .wma files, I can’t get mine to play them. However, it plays .mp3 and .m4a files just dandy. This is great as I wasn’t looking forward to converting my music to Microsoft .wma on my Macbook.

Also, I could only receive files from my phone and not send to it until I updated the firmware (Settings -> Phone Info -> Update Phone SW). Now everything works great — file transfer, iSync.

Ringtones can be created by renaming an .mp3 file as a .qcp and saving it in the audio directory. It is picked up from there just fine. Use bluetooth file transfer for this.

Something else that is neat is playing videos. I can take a video, say a movie trailer, and using Quicktime export it to MPEG4 (176×144) and upload it to the video folder. Then I can watch it fullscreen (though you have to hold the phone sideways because it is widescreen) using the video player. It’s really too small of a screen to be useful, but it’s still cool. Here is the trailer for the movie 300 and the Daily Show (Nov. 15) formatted for the RAZR.

300 Movie Trailer [2 MB]
Daily Show 11/15 [25 MB]

Unzip and put in /MMC/DCIM/video on your phone. You can play them by going to Pictures and Videos -> My Videos -> External Memory.