• Notes to myself: Minibog improvements

    I’ve been growing some small carnivorous plants (mainly Nepenthes and sundews) in a tank indoors, but a couple years ago, just for fun I started some Sarracenia (pitcher plant) seeds. Well, what do you know, the darned things actually grew. So this spring, when it was clear I wouldn’t be able to keep them in…

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  • PID control stove hack for better brewing, sous vide, etc.

    “Cook all the foods, hack all the things / Make all the booze, hack all the things” In beer brewing, the temperature profile during mashing has important implications for the beer’s eventual body and “mouthfeel”. The requirements for partial mash brewing are a bit more relaxed than all-grain, but still matter (the enzymatic reactions occur…

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  • Notes to myself: Lulzbot TAZ n00b guide

    A work in progress… Critical Specs: Bed size / Build envelope: 298mm (X) * 275mm (Y) * 250mm (Z) Nozzle diameter: 0.35mm (shipping default; others available) Filament diameter: The TAZ’s extruder expects 3mm filament. However, not all off-the-shelf filament will be exactly this diameter; the discrepancy could affect print quality in severe cases (see notes…

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  • Tim Tears It Apart: Sensitech TempTale4(R) data logger

    One of these devices appeared in a large shipment of temperature-sensitive raw materials at my work, amid a pile of dry ice chips. While I don’t know the MSRP or actual retail price of this gadget, the shipper packs one in with every order and tacks on $60-70 for it as a line-item; nonreturnable as…

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  • A new feature: “Tim Tears It Apart”!

    So, as you might have guessed, I’m an electronics engineer, and I like to tear things apart – especially gadgets. I don’t usually post about it, because a) someone else has probably already posted a teardown of that gadget, and b) I’m lazy as balls. But then I realized a good teardown is not all…

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  • Notes to myself: Test a Bluetooth Low Energy device on Raspberry Pi, the quick way

    Testing if the new nRF8001-based Mosquino BLE shield I built actually works. With the unmodified library and example code, it purports itself to the a Nordic heartrate monitor. Much of the below based on Michael Saunby’s blog post on checking out a TI SensorTag. Install bluez and hcitool (plus any dependencies). As of today, current…

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  • AllElectronics “Mystery Infrared Device” with LIRC

    NOTE: This device is no longer sold; rescuing this information before it disappears from various caches. Description of the device from AllElectronics: Our best guess is this is an infrared receiver/ transmitter for use with televisions or other remote-controlled equipment. Made for OnCommand™, it consists of a small black box, 2″ x 1.95″ x 0.6″…

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  • Refraction Fail

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  • Fun expression of the day: “flip a coil”

    There is supposedly an Afrikaans expression that translates as “flipping a coil” or “flipping the cone”, etc. Kind of a more evocative equivalent to “shitting a brick”. It refers to the act of turning one’s underwear inside-out to dump out the results of having shit one’s pants, e.g. due to extreme rage or surprise. The…

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  • Rez Trance Vibrator mystery LEDs, and how to control them

    So, a friend of a friend recently managed to buy the original Rez, complete with new-in-box Trance Vibrator. But the peripheral didn’t work – it would be detected, but otherwise not do anything. Knowing I had produced a compatible open source version of this hardware, she brought it over for a look. The motor was…

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  • Solar seed warmer to get a jump on spring

    Spring is coming… here is a tiny little hacklet from the bench of Tim. I live in New England. I don’t mind it here, but the growing season is a bit short. So here is a scheme to give outdoor direct-seeding a little head start. Seeds for many food plants, such as melons and peppers,…

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  • So, it appears MakerBot have gone full evil now…

    We shuddered when it was announced that MakerBot were taking the next version of their RepRap-based printer design closed-source. We crossed our fingers when the CEO responded to the flap saying they’d be “as open as possible“. We watched with popcorn the various flaps about Thingiverse, legal mumbojumbo, attribution and moral rights. But now this.…

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  • CNC milling custom 40DP timing belt “gears”/pulleys

    Woo, it’s been a long time since I messed with pick & place stuff. Bad Tim. An irritation I have been having is making everything work using reliably sourceable, off-the-shelf parts (not lucky eBay/surplus finds). In particular I’ve found small “tin can” stepper motors are hard to source in small quantities repeatably, and once you…

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  • Fun with cheap TV-tuner dongles and Software Defined Radio (SDR)

    So, last week I joined the bandwagon of exploring software-defined radio (SDR) via one of those super-cheap Chinese TV tuner USB sticks. In a nutshell, the idea of SDR is that, rather than the traditional approach of building dedicated radio receiver hardware for each possible RF band and modulation type (here’s your AM radio, here’s…

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  • Notes to myself: Using EnergyMicro EFM32 with GCC open-source toolchain

    The EFMs can be used with many different toolchains after installing EnergyMicro’s “Simplicity Studio” package, which includes board/chip support packages and some code examples. EnergyMicro’s application note AN0023 has an overall good overview of setting up an Eclipse + GCC (CodeSourcery) toolchain. Nevertheless, in attempting to replicate this process on my Win7 system (work PC;…

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  • The IOC, Trademark Law and You

    Yes, it’s true! With the London Olympic Games and Paralympic Games Act 2006 (UK), and similar laws pushed through in other countries as a condition of hosting a certain large quadrennial event (US- Amateur Sports Act of 1978; Canada- Olympic and Paralympics Marks Act), any infringing use of IOC ‘properties’ (similar to, but stronger than,…

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  • Buying Parts

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  • Solved: Can’t connect to high (>10) Windows COM ports / cleaning out unused COM ports

    Problem: Windows, and many Windows apps that use serial (COM) ports, have various problems accessing “high” numbered COM ports. I cannot find an authoritative or quantatative definition of “high” (and it may depend on your app), but I have seen apps start failing after COM8, COM9, COM15… anything in the 20s is asking for trouble.…

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  • Solved: SL4A force close when calling recognizeSpeech

    Problem: SL4A crashes upon the first call to recognizeSpeech() : com.googlecode.android_scripting stopped unexpectedly (Force Close). The corresponding Android log via adb shell #logcat: D/AndroidRuntime( 2785): Shutting down VM W/dalvikvm( 2785): threadid=1: thread exiting with uncaught exception (group=0x4 0018560) I/ActivityManager( 1429): Starting: Intent { act=android.speech.action.RECOGNIZE _SPEECH } from pid 2785 E/AndroidRuntime( 2785): FATAL EXCEPTION: main E/AndroidRuntime(…

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  • Computer-controlled RGB LED Buckyball

    Everyone and his brother has built LED cubes before, and while they are unmitigatedly awesome, I wanted to try something a little different. As far as I can tell, nobody has made an LED buckyball before! And of course, the requirements for such a large, sparse shape are a little different. In a typical LED…

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