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My Eagle Library

Posted 2012.08.19 9.06 in Computers/Internet/Technology

In my recent electronics adventures, I’ve had to learn to use Eagle, and in using Eagle, I’ve had to create some parts layouts.

I’ve a handful of parts (packages and symbols) set up. A few are mostly for reference, eg. items I created in order to make the schematics of my Thermostat V3, or the current prototype of my ISEB-6. The symbols are ok, but the packages (board footprints) are not tested and probably not accurate.

Other parts, that I have set up while working on the ISEB-6 Mark-II are more certain, eg. the TQFP-44 footprint for the ATMega1284P, surface mount TMP-36, et cetera. These parts’ footprints are tested and known good.

I’ve left comments in the library to indicate which ones are known to be good and which ones aren’t.

You can download the library by clicking right here: Stephanie’s Eagle Library.

Got Some Soldering Done

Posted 2012.08.14 8.20 in Computers/Internet/Technology

This past weekend I got the new version of the ISEB-6 mostly soldered out.

It all went together fairly easily, with two unfortunate exceptions. The BMP085 barometric pressure sensor, and the HMC6352 magnetometer/compass. Both components are surface mount ‘leadless chip carriers’ – and both proved harder to hand-solder than I expected.

The thing is, unlike the ATMega1284P which is a TQFP-44 or the few SOT23 parts — all of which have ‘pins’ sticking out (albeit tiny pins), the two aforementioned sensors are in LCC packages where the connections are all underneath the part. There’s nothing visible from ‘above’.

I had some tricks in mind to solder them, and the tricks failed. In the end, I unfortunately destroyed both parts. Boooooo. Fortunately I did have a spare BMP085 laying around, but the HMC6352 is kinda-expensive and I didn’t have a spare.

Also-fortunately, I had a backup plan for soldering these tricky parts – hot air. I have a Sparkfun Heaterizer XL-3000 which I hadn’t actually used before. It did the trick though, allowed me to remove the dead parts without destroying the rest of the ISEB6 board, and I was able to solder the new BMP085 with it.

When I get a replacement HMC6352, I’ll use the Heaterizer once again to get that in place.

After that, the next steps will be to assemble a new leather bracer, and then build it out, with all the peripherals.

Integrated Sensors Electronic Bracer

Posted 2012.05.27 23.34 in Computers/Internet/Technology, Hobbies

Introducing the Integrated Sensors Electronic Bracer (6), or ISEB6, a wrist-mounted sensor platform.

A comfortable wrist-worn leather bracer, that provides: time & date, compass heading, Exposure Value for photography, positional data, walking tracker (distance, time, average speed), galvanic skin response data, local temperature and humidity data, “alarm-clock” functions (alarm by time or countdown seconds alarm), and simple illumination / flashlight functionality.

The ISEB6 is powered by a small / lightweight Lithium-Polymer battery, running up to 48 hours usage on a single charge, and with a simple & fast on-board recharging system.

The ISEB6 is based around Sparkfun’s Pro Micro development board and Adafruit’s SSD1306 OLED display screen. The number six in the name refers to the number of sensors integrated into the bracer. It contains the following sensing circuitry:

  1. Illumination is measured with a TLS2561 digital luminance sensor.
  2. Magnetic fields are measured with an HMC6352 digital magnetometer.
  3. Location is detected with an MTK3339 GPS module.
  4. Humidity is measured with an HIH4030 analog sensor.
  5. Galvanic Skin Response is measured with a simple resistor dividor and gold-plated electrodes inside the bracer.
  6. Local temperature is measured using the on-board temperature sensor in the ATMega32u4 microprocessor.

In addition, the ISEB6 also utilizes two voltage sensors, but as these only monitor its own internal status they are not counted among the ‘listed sensors’.

Read more »

Oh. My. Goodness.

Posted 2012.05.20 7.51 in Computers/Internet/Technology

I have to confess, when I soldered the final power connection and this came to life on my wrist, I kind of geekgasmed a little bit.

Yes, I mounted the parts and did the final soldering with it already on my wrist. It was the only way to be sure things would have the right fit and feel. And it was damn fun too, despite being awkward – soldering iron in my right hand, holding the solder in my teeth, keeping my left hand still…

In the photo above, it’s still ‘just’ the bare circuitry and power supply mounted to a leather bracer. There is still some debugging to do of the software. And I have to finish the exterior.

When completed most of the goodies will be hidden under a top layer of leather, with openings of course for the screen, light sensor, etc. but the idea is that the delicate parts will be protected.

The only thing it doesn’t have yet, is a proper name. It’s kind of a wrist computer, except it’s not really a computer. I’ve been jokingly refering to it as the Wrist-mo Comp-ulator. I’m not sure I want that name to stick.

Thermostat Three

Posted 2012.05.09 21.27 in Computers/Internet/Technology

This might just be the fastest project I’ve ever done. Saturday morning I started the hardware build, by Saturday evening I had also begun the software. By Sunday afternoon I was halfway through. Sunday evening saw it 90% completed. Monday was finishing touches and adding some extras just because. Tuesday I finished it. This afternoon I installed it.

Some of the things that aren’t obvious in a still photo: The the block above the screen has two RGB LEDs behind it. These aren’t programmable, but one cycles through the colours slowly and the other does so quickly. Together they provide a sort of swirly multi-colour effect that I think is reminiscent of ST:ToS effects.

The red circle ‘red alert light’ is wired to the XBee’s RSSI so when the XBee receives a wireless command, the red light comes on for a few seconds.

The white gridded rectangle is the DHT22 sensor (temperature and humidity). I felt it would ‘blend in’ enough that it should be mounted right up front for all to see. The little black hole to the right of the DHT22 is for the light sensor.

Why is there a light sensor? Why not? Also: because I had an extra one laying around.

The screen display is mostly self-evident. Time, day, date. Heat/Cool. Run/Hold/Override. Target temp (small) and actual temp (large). Fan status (on/auto) and humidity.

The last line is EV (exposure value) and free memory. That’s 657 bytes. Not kB or MB, just bytes. It probably won’t ever change but it’s there just because there was space for it.

The following images have some more build details / information:

The sketch code, and a text file with lots of my design and build notes, can be downloaded here: Thermostat_3.zip

Another Work In Progress

Posted 2012.05.06 16.47 in Computers/Internet/Technology

Because I can have more than one project on the workbench at any given time. The more the merrier! Though I really ought to actually complete something eventually. I guess.

Anyhow – the Sneak Peek project from a few days ago is on a very brief hiatus as I await another component or two, so I thought Hey! I should build another thermostat!

The original was kind of drab and beige, with a lot of sloppy workmanship. Version two is sleek and translucent, and the workmanship is a little nicer. Version two looks very technical, with exposed circuitry and insides.

The problem with #2 though is that it didn’t cover all the holes and paint-outlines from the original antique non-DIY thermostat. So in order to hide the holes and mismatched paint, the obvious solution was a thermostat with a larger footprint. Making it super-geeky and sexy is just a bonus.

See, I had this Star Trek thingy from Think Geek, but it’s sound effects were really annoying and useless. Pretty though – a perfect enclosure for some kind of project. Toss in an LCD and some sensors from Adafruit, and an Arduino Pro from Sparkfun, and voilla – Thermostat!

I just need to wire in some relays and then it’ll be ready to hook into the house’s HVAC system. Maybe another week or two (unless I get distracted by something shiney) then I’ll post a detailed write-up and code.

Sneak Peak

Posted 2012.05.04 8.48 in Computers/Internet/Technology

I know I’ve been mighty quiet lately. It’s a combination of busy at work, busy with projects at home, and being extra-exhausted in between. Oh and not having much to say, really.

Anyhow, here’s a sneak-peak at one of the projects I am currently working on:

Obviously we’ve got the time and date there. EV refers to Exposure Value, it’s a photography thing. Then there’s a compass readout, in degrees. Then there’s lat and lon, as well as altitude and signal strength, coming from a gps readout.

All of this (except the USB cable of course) fits in a space smaller than a business-card. Just add some buttons and a battery and…