Hacking Capacitive Encoders

Mar 102012

Gutted Digital Micrometer

A long time ago a friend of mine, and I, decided we were going to build a capacitive encoder. Our big idea was some 15 years ago when we were a bit younger (and more foolish). My friend took the guts from a digital micrometer and mounted it all to a large Plexiglas block. One of us mounted a wires to all the pads around the perimeter of the sensor. The pads allowed us to probe the signals on the pads. This poor little encoder is amazing, it has a resolution of 500 counts per revolution.

Typical Digital Micrometer

RC Transmitter / Control Anything

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Mar 012012

HobbyKing $23 Dollar HK-T6A 6Ch Radio

I recently stumbled upon how easy it is to hack into / repurpose the HobbyKing 6 Channel transmitter / receiver RC radio. The specific model I’m using is the HK-T6A V2 6 Channel 2.4GHz transmitter and receiver pair. This is an awesome hacker’s delight mainly because of the price. At just $23 bucks you just can’t go wrong. Note, I have zero affiliation with HobbyKing – I simply think this radio transmitter / receiver pair is amazing considering the price versus functionality / performance. This radio is designed to transmit up a mile without any glitches so you can fly your RC airplane without any problems. There is some crappy HobbyKing software you can get to reverse and mix channels. To use the software you must purchase a special USB to Radio cable from HobbyKing. At only $3 bucks I bought one just to see what extra “features” I could play with. All cheap fun!

Anyway, read on for the hack to control anything with this transmitter (for now on known as Tx) and receiver (for now on known as Rx).

*** Note, I’ve only tested this method with this particular HobbyKing radio Tx / Rx pair. You’ll have to test your radio to verify it operates in the same manner to use this hack.

Pinewood Derby Mars Rover

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Feb 182012

Pinewood Derby Mars Rover

Hey Pinewood Derby Race Fans!

Need an idea for this coming Pinewood season? Have a look at our Mars Rover from the 2012 race season. I’m proud to announce we won first place for the “People’s Choice” award. Good thing too, this car design is not the fastest car on the track.

The three blinky LED lights are all hacked from other sources. The big dish on top came from K Mart. The dish was a sphere before we broke it open. It was originally designed to float in a fruit punch bowl. K Mart sold them as a pair for $5 bucks.

The two tail lamps were tea LED lights. Bought these in the grocery – these can be had for around 30 cents each. We hacked them down and be smaller then the originals. The on/off switch also got reworked so that it now accessible along the back edge. Otherwise, the switch points out of the bottom of the lamp.

The top deck is covered in aluminum foil. The bottom chassis is covered in copper tape. The copper tape was some 1″ sticky tape I’ve had forever, and a day. The two covering gave the car a nice two tone look. Note, the middle wheel is non-functional and is mounted a full 1/4″ above the track.

Well, hope this give you some more ideas for you next car. If so, post some comments below.

Hacking “Holiday Living” Tea Lights

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Dec 312011

Holiday Living LED Tealight

Just goofing around today with all my Xmas stuff. Thought this might be interesting to someone.

Have you ever wondered what makes one of these LED lamps flicker? I did too. So, one of the lamps had to volunteer to be opened up for a little closer inspection.

I was shocked at the simplicity of the lamp. One CR2032 coin cell battery keeps the lamp flickering for hours. Saying the lamp is flickering is a stretch. Seems more likely the lamp is randomly jumping between half a dozen set PWM values. Still, how do they do that? There is just the battery, a switch, and an amber LED. How does the LED flicker at all?

Well, turns out, the LED has a tiny ASIC built right into the plastic of the LED. The tiny ASIC is “encapsulated” into the LED itself.

Below are a some more closeup pictures of the LED. I took these pictures by holding my little camera up to the eye piece of my microscope. Continue reading »

Muffin Fan Based Tin Can Wood Gas Camp Stove

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Nov 242011

Wood Gas Camp Stove - G4

Yet another tin can wood stove, I know, I know. Still, I’ve discovered a few things that may make your next stove build a little easier. What follows below are my trials and tribulations at build a really good working camp stove. Note, I’m still experimenting with certain aspects of the design. Always more experimenting to do.

My inspiration came from an article in Make Magazine which described building a tin can wood gas camp stove. Here is a link to the Make magazine article. The Make article inspired me to build my own stove. My primary goal was to be able to boil water (for instant coffee) while on Boy Scout camp-outs. Oh I know, it would much easier to build an alcohol stove (much cleaner and all – and easier to build too). However, there is something cool about being able to cook using wood. Plus, wood is in endless supply while on Boy Scout camp-outs. Will be nice to have a little stove heater on cold winter camp-out nights. A stove heater that I don’t have to worry about in terms of running out of fuel! Oh, I know what your thinking, “What about the battery for the muffin fan? Won’t that go flat in a hurry?” Well, using 2500 mA/hr batteries we’re looking at over 30 hours of run time. Continue reading »

Hello WordPress!

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Aug 052011

Making the Switch

I’m making the switch from Drupal to WordPress today! Now, it’s just a mater of porting all my old junk over with me.

Thanks,

Jim

TI Evalbot Review

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Apr 122011

Quickly little post concerning my recent messing around with my new TI Evalbot.

At $150 bucks this is not an inexpensive kit to buy. Below are a couple of pictures and my first impressions.

The kit is rather easy to assemble. However, the wheels are tough to assemble. The PCB wheel plates press onto the shaft of the motor. Three plates then must be aligned so that two set screws can be screwed through the three plates. It takes a lot of force on the poor motor to get all the plates and set screws mounted.
Continue reading »

Building a Super Computer

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Mar 022011

Comes a time when pushing old hardware to perform new task just gets to be too much. For me, using my 2006 Linux laptop + VMware / WinXP became just too much. However, I haven’t built a machine from the ground up in many years. I was rather worried about getting all the right parts to match. Heat is always a concern too. The new Intel micros are know to be monster heat generators. Oh, and I hate noise too. My old Dell XPS had a nasty whine. I’ve had bad experiences with Dell desktop machines too. OK, OK, I know what I don’t want. What i DO what is a quite Super Computer!

Below is a laundry list of parts I skimmed off Tom’s Hardware web site. Their web site is handy for describing hardware builds. Problem is, seems like they are all about building gaming systems. I just want a rock solid engineering machine. Don’t get me wrong, I seem to find ways to choke PC hardware just as fast gamers.

Improved Electric Socks

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Jan 272011

New & Improved LiPo Power Electric Socks

Just a couple of updates regarding the electric socks.

The biggest improvement was shortening the battery cords. The existing cords were a pain in the butt to coil up into a coat pocket. I also added a health amount of hot glue at the opening of the tick-tack box. The hot glue provides strain relief to the wires entering the tick-tack box.

I have some results. After using the socks for several hours (maybe four or five hours) I decided to recharge the LiPo batteries using my new Thunder T680 LiPo battery charger today. Each battery took 50 minutes to recharge (2 Amp charge current) and, according to the charger, stored 1330mA back into each. So, given these are 2200 / 2450 mA*Hr batteries, just over half the battery capacity was consumed yesterday.

Electric Heated Socks

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Jan 262011

LiPo Powered Electric Socks:

This winter has been cold, in fact, really cold! That coupled with the fact that I can’t seem to find boots that will keep my feet warm. And now, we’re getting ready to head off this weekend for a Wacky Webelo Weekend. I’m a gonna be outside for two days strait. How the heck can a poor old man keep his feet warm? Of coarse the answer is, for any good electrical engineer, is to apply some electronics to the problem. My solution involves electric socks plus a couple of LiPo batteries.

I bought the socks 10+ years ago when I was an employee of Motorola. I was a resident engineer at General Motors on the Saturn program. Motorola manufactured the engine control module. Anyway, I was asked to attend their winter testing in Kapuskasing, Canada. The Kapuskasing GM proving ground are 500 miles due north of Detroit. We spent our days starting Saturn vehicle that inside cold chambers at -40 degrees C. Continue reading »

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