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Books I’m giving my brother for the holidays

December 21, 2014

Last year, I gave my brother a bunch of books for the holidays. He professed to enjoying receiving them all. He hasn’t said which ones he liked reading. But, as a I said last year, we aren’t great communicators.

I also suspect he most liked me setting up his email even more: a “friend” had previously set up his email and it intentionally misspelled my brother’s last name. I, of course, sent the gifts to the correctly spelled name, my head being unable to cope with that sort of breakage. Anyway, I made a corrected email address and then forward the old account to the new one and sent him all the passwords (which he expected me to remember this year, hah!).

When I called to ask for his daughter’s addresses, we chatted for a few minutes. He said he’s reading a lot these days and would love more books, especially science fiction. I got excited, exclaiming I have the perfect gift. Sadly, he’s already read Andy Weir’s The Martian– three times! At least I know I’m on the right track.

I made a new list, partially from the ones last year that I’d forgotten or fell off my list. So far I’ve already bought

  • Neil Gaimen’s The Ocean at the End of the Lane. I asked Chris where he thought someone should start with Neil Gaimen and he thought maybe American Gods and I thought maybe The Graveyard Book thought that is young adult. But when I thought about about really-good-books without taking into about the author, The Ocean at the End of the Lane is higher in my personal ranking.
  • Ernest Clines’ Ready Player One. As soon as my brother said The Martian, I thought about Ready Player One. I don’t know why they are linked to me, maybe because I wish I’d written these books. No, not because they are popular but because they are deeply harmonic with the noise in my head.
  • Keeping with fiction, I went ahead with Ender’s Game. In Amazon, it is filed under “Classic Science Fiction” which where it belongs. The movie was not as good as the book (in large part because you couldn’t get a kid as young as in the book). I don’t necessarily like Orson Scott Card and I think the Ender books went on for much too long. But this is a great book and it was on sale.
  • Brandon Sanderson’s Mistborn Trilogy. Chris introduced me to this fantasy trilogy. Sanderson is so prolific, it can be tough to figure out where to start. This trilogy is fairly well encapsulated and a lot of fun. I have only dipped my toe in his other work though Chris gets lost in it.
  • Matthieu Ricard’s Happiness. Written by a molecular biologist turned Buddhist monk, I suspect my brother will like this book more than I did. I quite enjoyed the first 25% and then it lost me a bit in the deeper areas of Buddhism. I’m fully willing to believe (and practice) that happiness is a skill that requires practice and attention. However, I’m a product of Western education, the eradication of self is inexplicable to me unless he means balancing the System 2’s lies to cover System 1’s laziness (from Kahneman’s Thinking, Fast and Slow). That makes sense to me but I’m not sure that’s… Anyway, my brother mentioned an interest in Buddhism and Happiness is the obvious book for him if not for me.
  • Randall Munroe’s What If? Ahh, come on, we all read the wonderful XKCD webcomic with its mix of absurdity, love, and science. And I read the What If? blog with great enjoyment. I suspect my science-loving brother will love this though I worry that he may not be familiar with Munroe’s other work. I wonder if that will decrease his overall enjoyment, I hope not.
  • Allie Brosh’s Hyperbole and a Half. Last year, I got the hardcopy of this for several people. My brother-in-law never laughs aloud and he giggled through it. A visiting friend seemed a bit depressed (in part because he was visiting over Christmas to meet stupid work deadlines and because his cat had recently passed away) and we put this in his stocking, getting a few giggles from him as well. It is a great book that covers some fairly deep territory with panache (and humor). I recommend it to everyone. Though I’m concerned about the color images on a kindle (my brother said he had a color screen, I hope it all works out).

I started working on this list last week, making an Amazon gift list so I could pile ideas together. Strangely, this shows me just how much the prices fluctuate. Both What If? and Hyperbole and a Half were discounted 30% when I went to look today (and add another book I was thinking of). Now, I’ve decided to go ahead and leave the list a little broad, maybe a few more things will go on sale, helping me decide what else to get my brother. Some of my other ideas:

  • In the popular science category, I have: Ken Jenning’s Maphead about incredibly interesting subject of geography (yeah, I didn’t think it was possible either), Sam Kean’s The Violinist’s Thumb about genetics (and history of discover), Micheal Pollan’s The Botany of Desire about plants mating habits and how they’ve trained humans to care for them, and James Pennebaker’s The Secret Life of Pronouns about the wonderful world of words and the psychology of interpreting what someone means. Vladimir Dinet’s Dragon Songs about crocodilian (and Russian) mating habits almost makes the list but I think that was because I listened to part of it which set the voice in my head better than the writing did.
  • In science fiction, I have Douglas Adam’s The Ultimate Hitchhiker’s Guide to the Galaxy which contains all five books. I should just buy this one. It is a little pricier than the cheap ones but, gosh, at a per-word price it is improbably cheap. Heck, I should get it for myself, it is time for re-read of these, they make me happy. Talking about a good value even at full price, my list also has Neal Stephenson’s Reamde. What a romp! But my brother isn’t into computers so the attention to detail may be lost on him (and I already got Ready Player One which is somewhat similar).
  • In fantasy (I don’t normally separate sci-fi and fantasy, any advanced technology looking like magic and whatnot, but that previous bullet was getting pretty long. To keep this short, I’ll just put up some books.
  • Last year’s gifts had a lot of urban fantasy so this year, I tried to be shorter in that. I liked Mur Lafferty’s The Shambling Guide to New York City (and the New Orleans sequel). For all that these are full of dead things, it is a more character driven book than some of the others on the list. Other urban fantasy and some pithiness:
  • Back to science fiction or fantasy or whatever
    • Jumper (I love Gould… though I started with Wildside so maybe that is better. But Exo came out this year (Jumper #4) and so this is better path)
    • The Curse of Chalion (Where to start with Bujold? Vorkosigan is awesome but this is standalone. And awesome. But on the pricey side)
    • The Three-Body Problem (I am so looking forward to reading this book myself! I have such high hopes. This may be an example of giving a gift to someone else and hoping they don’t like it and give it back.)
    • Boneshaker (I remain a sucker for Steampunk.)
  • Last (but not least), I really enjoyed the The Best of Instructables. I seldom go to the website (being ad-phobic) and having them in a book has been awesome for inspiration and general interest. But I’m not sure about Kindle. I’d consider sending him Make Magazine but I’m not sure he’d be into that.

Having learned the price fluctuations in ebooks, I’ll watch them for a day or two and sort out what else to get my brother. Though if I was in charge of making profits at Amazon, now that the shipping window is nearly closed, it would make sense to push the prices of all electronic items up a bit for those last-minute shoppers.

What did I miss? Any books you especially enjoyed this year?

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Debugging

December 17, 2014

A podcast listener requested a show about debugging. I’m still working out just what he meant by that but between that and working on a Trinket, I find I have a few things to ponder aloud for you.

First, the Trinket is a small board with an ATTiny85 on it. It is a very low power, deeply embedded sort of processor. With all of 8k of code space and 512 bytes of RAM (and 512 bytes of EEPROM), this is a dinky little thing. Plus, with the on-board bootloader, there is only about 5000 bytes of code space. I feel like a kid again.

So why in the world would anyone use the Arduino interface with this? Well, it is what I have, it is what Adafruit had in their tutorial, and I’m too unmotivated to set up a GCC cross compiler (yet).

Usually when I use the Arduino compiler, it is with a proper Arduino board (or the MicroView which is a “proper Arduino board” for this discussion). Debugging is done via printf because there is a serial connection via USB after the bootloader has finished programming the board.

Under “Debugging Tools” on my resume, I have “DVM, oscilloscope, logic analyzer, JTAG, ICE, printf” so I’m fine with printf as a way to determine what is going on with my code. On the other hand, if I can have an on-chip stepping debugger, I much prefer that. But that isn’t an option with the Arduino compiler so I limp along. Nothing I do on an Arduino is all that complicated.

All that said, the ATTiny doesn’t have the serial debug interface. There is no on-chip debugger and no printf. That means debug is usually through GPIO lines and prayer.

There are tools that could help me. I think. But I’m trying to do it the way everyone else is. Or the way I think they are. I’m writing little pieces of code and running them. I’m blinking the little onboard LED once for good, three times for an error. It look a stupidly long time for me to figure out why my byte variable wasn’t getting to 256. It isn’t impossible to work like this but it is a lot harder.

So, yeah, maybe it is time to talk about debugging. We could start with Arduino (and mbed) and debug through printf. Then go into the tools available for that space. Then the SWD interface for the ARMs (i.e. Cortex-M0). What are ITMs and ETMs anyway? We could talk about timing errors due to debugging (both serial and on-chip). We could talk about the extras that are available on some IDEs (mmm… profiling and backtraces!). We could talk about GDB, how it is super powerful but opaque and a pain to the beginner. We could even talk a bit about data logging and error handling (other listeners have requested shows about these).  I wonder if we’d even get into unit tests since some systems I’ve developed for run on-target-hardware via debugger.

I feel a lot more secure and confident when I can see what my chip is doing. I don’t mind using printf but I’m better at getting things done with better tools. Most tools are cheap compared to my time.

So yeah, debugging…

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Another Day of Battery Life

December 16, 2014

To make a ring, I needed to minimize everything. Of course, if you’ve seen the picture, you already know I didn’t actually minimize much.

Still, batteries in wearables are a pain. For this wearable with my “you have to take it apart to charge it” methodology, well, longer battery life means this hack will exist longer. The more I take it apart, the more like it is that I’ll repurpose the parts to do something else. (I have this idea for a different ring…)

Minimizing power in Arduino is a topic that has been taken on by plenty of other people. And I happily reused their code and methods(Thank, you Nick Gammon!).

However, when planning a device, it is helpful to determine the size of battery you need. To that end, I made an Excel sheet (sorry, I default there) which I’ve put into a Google spreadsheet so you can see it with the math. The first sheet (words) describes the process in words. The second sheet (numbers) reflects the same information but with numbers. You fill in the orange boxes, it generates the green one.

The first step is to determine the different power states of the device. For Wordy, it is either on (display showing) or sleeping (Arduino asleep, accelerometer configured to wake and interrupt it).

 

My next step was to figure out how much time the system would spend in each of these states. My goal is for the ring to be on for about five seconds every five minutes. Sometimes it will be on more, as I play with it a lot. More often it will be sleeping, such as left on a table overnight. (Note: if you build a Wordy, I strongly recommend setting the ring so it will lose at Pong. Sometimes if you leave it on the X side with no Y tilt, the ring will play Pong by itself indefinitely.) Starting with the idea of five seconds per five minutes means I’ll probably be on the conservative side (unless it plays a Pong marathon without me).

Next, I measured how much current each state. I used my shiny new DVM-with-current-sensing (my old one didn’t have that (though it did have a more melodious beep in resistance mode)). You can use a resistor if you feel like doing it old school style.

(This pic is from my book. If you were unaware I wrote a book, well, yes, I did and it is full of jokes. And dinosaurs. But mostly embedded systems.)

Finally, I calculated how long the device would last given a 40mAh battery (the largest I was willing to use due to size constraints). The result turned out to be much greater than I expected.

This does not have to be the order of events: you might start with the idea of how long you want the device to last and choose the battery accordingly. Or you may have a fixed battery and a predetermined life and need to determine how much time you can spend in each state. Happily, the math works in all the different ways.

Note that this value I got was greatly in excess of my self-imposed goal (which was a puny two hours). It is also greatly in excess of what I said in the build instructions (which was 48 hours). My wear-time was even greater than the estimated value: I charged on Tuesday afternoon and it died on Saturday night.

Though, I’m pretty sure I can do better than these power numbers.

When I measured the MicroView without the accelerometer, the on-state power fluctuated between 10mA and 14mA, depending on how much of the screen was lit. (All current measurements were taken around 3.7V.) If I modify numbers on the spreadsheet, the on-state power of 10mA to 14mA, it changes from 3.5 days to 3.1 days. I switched it back to 12mA as reasonable middle ground.

The accelerometer doesn’t add much to this on-state value. On the other hand, for the sleep-state power, it is a very different situation. The MicroView alone took 0.14mA. The MicroView and accelerometer together take 0.31mA. If I change the sleep-state power from 0.31mA to 0.14mA, the amount of battery life expected changes from 3.2 days to 4.9 days.

The accelerometer datasheet says the accelerometer’s current consumption is 6uA to 165uA. Looking at the numbers above (0.31mA-0.14mA = 0.17mA ~= 165uA), it is clear I should be able to reduce the sleep-state power by reading over the accelerometer datasheet again. (There is also an application note about wake/sleep features.)

Skimming through the app note, I don’t care too much about the precision of the data (though I might in Pong mode but that is an active mode so it is ok to use more power there). It would be no problem to turn the system from 14-bit mode to 8-bit mode.

Sleep mode is limited to 50Hz sampling but that is what I’m sampling at anyway. Why am I still seeing the max current?

Ahh, according to the oversampling chart, I may see 165uA due to high resolution sampling. I can go to 24uA with normal sampling or 14uA with low power. However, I want some filtering either through oversampling or via the low noise setting. The combination of low noise + low power is back to 24uA.

Making only one change (from high resolution to normal sampling) should be enough to increase my battery life from 3.3 days to 4.6 days. That’s exciting. Excuse me, I need to go see if that’ll work and what else I need to change.

[Note: this was crossposted from Wordy’s Hackaday page project log.]

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Hackaday: Wordy

December 9, 2014

I wanted to make build instructions for Wordy but since it uses both SparkFun and Adafruit parts, I couldn’t decide where. Though I did say I was going to put my next project up on Hackaday. I did that. There is a link to the code there as well as build instructions. Anyone here want to check it out for me? Maybe suggest what I forgot?

Wordy Ring

One thing already on my list is a project log of different ring making methods I tried. I’m going to do another pass with Sculpey, taking pics as I go. I also need a final picture of it all together, I plan to take that when I wear it out tonight.

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Call for Proposals

December 4, 2014

The embedded systems conference (finally renamed the “Embedded Systems Conference”, yay!) and O’Reilly’s Solid conference have opened their call for proposals (Solid’s and ESC’s). After telling everyone that I’m tired of giving conference presentations, tired of attending conferences without talks that I want to see, that presentations take way too much time to prepare, presenting leads to no goodness for me, I have nothing to talk about, and I have way more fun (and reach more people) on the podcast, I’ve put in three proposals.

Faker to Maker in 30 Minutes

The Maker revolution is obviously here.

What does that mean for those of us who aren’t Makers? We worked hard for these engineering degrees and now sometimes feel daunted (even intimidated?) by the free sharing, open source, do anything, tinker in their obviously copious spare time hackers.

Wait, weren’t hackers the bad guys? (Sometimes, semantics change.)

Will there still be a space for careful, professional engineering? (Hint: yes.)

Most importantly, how can we join forces to get the best of both worlds?

Low Power Strategies for Wearables (and Everything Else)

Sleep early and often. Reduce your clock speed. Turn off your IOs and unneeded subsystems.

Excellent tactical advice only goes so far, this talk will help you understand how to architect software to reduce power usage. Focusing on ST’s Cortex-M0 and Atmel’s ATMega328, Elecia White will describe how to start from a clean slate to get great results and how to utilize some of these techniques on to existing code bases.

Intro to Inertial Sensors: From Taps to Gestures to Location

What is the difference between an accelerometer, a gyroscope, and a magnetometer? What would you use each for? If you aren’t sure, let me explain.

The entertaining host of the Embedded.fm podcast, Elecia White will explain the differences and each sensor’s best uses, on their own and in combination. She will detail the most common ways to put them together and help you determine which are the best choices for your products.

The talk will discuss how to replace buttons with accelerometers, how that leads to gesture recognition, and why integrating to get location is a more difficult problem that it sounds. While you might not be able to implement a Kalman filter by the end of the talk, you will know why it matters.

***

What do you think? One fluffy and two technical. I had a third technical one but it seemed like an awful lot of prep work:

How to Choose a Micro for Your Application

Price, performance, and power war for supremacy. We all want the cheapest, lowest-power processor for our application. But at the beginning of development, we may not know how much performance we truly need. Choosing the wrong processor may lead to a complete redesign, a time to market disaster. How to estimate which family of processors is the best for your application?

Unaffiliated with any chip or compiler vendors, Elecia White is an experienced embedded systems consultant and host of the Embedded.fm podcast. She will explain her methodology, using examples across consumer applications.

The talk will tackle such estimation issues as where to start if you need to run WiFi—that often means running an Ethernet (TCP/IP) stack which means you probably need an RTOS. If you need an RTOS, you probably don’t want an 8-bit ATMega (not that it isn’t possible, just that it isn’t likely to be timely). Start with a Cortex-M3 range and look for the next set of requirements. Power might push you down to a cramped Cortex-M0 or heavy processing might sends you up to the Cortex-M4 (or a dual processor DSP/C-M0 option).

There are tradeoffs everywhere; this road map will help you choose a path.

***

That one also seems like one hundred thousand ways to be wrong since someone will always disagree. I can offer my opinion but I’m sure to frustrate some developer with a crush on PICs. (Because PICs are my least favorite processor. I don’t know why you’d choose a PIC over an ATTiny or an MSP430. Ok, I said it. AVR Freaks unite!)

Anyway, the proposals have been submitted on the idea that I should want to speak, that I should do my part for women-in-tech (bleah), and that I want more listeners for the podcast (which I should remember to mention this time, not like the last presentation I gave, urk).

The proposal deadlines are Jan 9th and 12th so get yours in. I’m only going to the conferences if there is someone I want to see speak. Go propose something amusing and informative, please.

 

 

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