Kevin M Lawson

Technology and Nonsense

Automated Undercover Mouse Postmortem

Last year I automated a cat toy and attached a Fitbit to my pudgy housecat in order to see if I could lower her weight. Eventually that cat did slim down to a normal weight, but it was ultimately due to low-tech methods; we got a new cat to chase her around and changed her food to a more healthy variety.

A reader emailed me inquiring if my modified Undercover Mouse still worked after so long and, if not, what shape the gears were in.

My modified Undercover Mouse worked for about six months. This was not six months of normal use but six months of relentless, automated, “wait two hours, randomly actuate for fifteen minutes, repeat” punishment. As time wore on I noticed the toy getting quieter and weaker. Eventually the wand would refuse to move but I could still hear the tiny electronic whine from the motor.


To my untrained eye, the gears look okay, so I would theorize that the little hobby motor suffered from some kind of internal wear. The toy likely did not break down from rough play by the cat, but instead by the 95% of those six months when it was running without the cat.

Given the ridiculous use that this little motor was exposed to, I would say it performed admirably.

Now it is time to order a new motor, and expose this toy to the new cat.

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Well here you go.

Introducing Colourama


A few weeks ago, I needed to make some color choices for a project. I decided to give COLOURlovers a try, and after I had spent an hour staring at pretty colors, I realized that I could make an amazing app just for staring at pretty things on COLOURlovers.

After a few weeks of tinkering and polishing, Colourama is the result. It’s free on the App Store. Go check it out.

How Much Exercise Does an Indoor Cat Get?: Week Six

I now understand why Snickers loves this toy so much and yet this love fails to translate into higher activity numbers: Laziness.


Speaking of laziness, I grew tired of having to track down the cat, remove her collar, un-tape the Fitbit Classic tracker, charge it for a few hours, and repeat the process in reverse every single week, all while losing (precious) data about the cat’s every step. Thankfully Fitbit now makes a perfect solution to my obscure problem: the Zip, a cheap, tiny, lightweight tracker with a battery that lasts six months.

Snickers with Fitbit Zip

The magenta Zip even matches Snickers’ collar. Note the blurry red wand at which she is staring.


Daily breakdowns (14 Jan to 21 Jan)

Daily breakdowns (14 Jan to 21 Jan)


Week summary (15 Jan to 21 Jan)

Week summary (15 Jan to 21 Jan)


Thirty day graph.  Zip activated on 18 Jan.

Thirty day graph. Zip activated on 18 Jan.



  • The daily breakdown graphs are visibly different after the Zip tracker was activated (9:30 on Friday, 19 Jan). The Classic and Zip trackers are both designed to count the steps of humans, and cannot be expected to accurately measure the exact number of steps of a twelve-pound quadruped, so this difference between the two is understandable. The general patterns of activity are still apparent so the Zip still seems like an excellent means of measuring general cat physical activity.


  • Tuesday evening (6:30-9) was the final recharge break for the now-retired Classic tracker. No more recharging! Woo!


This has been -and continues to be- a tremendously fun silly little experiment. Recently I have been busy working on other frivolous software endeavors, and my time for cat-entertainment-engineering has been limited. I will probably not do another detailed analysis post for a while; at least until I have built something new and had the opportunity to test it on the cat. An iPad app is halfway complete, and I’d like to do something with lasers.

In the meantime, you can continue to watch Snickers’ progress -every day- on her Fitbit profile.

Screen Shot 2013-01-24 at 5.43.49 PM

Cut-throat competition



  • The beginning, wherein I attach a Fitbit tracker to a cat
  • First week of data, when I learn interesting things about how my cat spends her time
  • Second week: introducing a new toy
  • Third week: automating that toy to (hopefully) provide the cat with more exercise
  • Fourth week: laughing hysterically at the resulting toy improvements and wondering if they are having an effect
  • Fifth week: looking at the results


How Much Exercise Does an Indoor Cat Get?: Week Five

So, did the ridiculously elaborate automated Undercover Mouse setup that I built produce measurable results?


2013-01-15 Snickers fitbit week five

Daily breakdowns (7 Jan to 14 Jan)


2013-01-08 to 2013-01-14 (week five) summary

Week summary (8 Jan to 14 Jan)



  • Weekend warrior: Snickers racked up 7,739 “steps” on Saturday, crushing her previous record of 5,477. Interestingly, Jennie and I were asleep or out of the house during most of Saturday, so it is possible that Snickers may play differently when left alone for longer periods.
  • Null hypothesis: Record-setting single day aside, the automated Undercover Mouse setup does not appear to have made a big difference. Snickers’ step totals remain around 30k/week.


  • Fitbit charging was performed from 6:30 to 10 on Tuesday evening (Jan 8). This is a bit longer than usual, as I accidentally left the Fitbit on the charger before we left for a fancy dinner party.  If Snickers’ activity was similar to her hourly average, those 3.5 hours work out to 650 steps; not a significant dent.

What’s Next?

I’ll buy some silly plastic cat toy off of the shelf while I work on the next ridiculously over-engineered cat annoyance. 

CatPlay iPad test

How Much Exercise Does an Indoor Cat Get?: Week Four

Heh. Cat videos: the currency of the Internet. Anyway…

2013-01-08 Snickers fitbit week four

Daily breakdowns (31 Dec to 7 Jan)


2013-01-01 to 2013-01-07 (week four) summary

Week summary (1 Jan to 7 Jan)



  • I topped off the battery on Tuesday (1 Jan, 9:30-10:30 P.M.) after seeing a low battery warning. I must have failed to properly seat the tracker on the charger during the normal Monday charge window.

Undercover Mouse: How Is That Going?

  • Anecdotally: Awesome. Snickers loves this toy, and now that it is automated she gets more quality playtime with it than even the craziest of cat ladies could provide. She has learned to recognize the sound, and will regularly trot downstairs with a few moments of it activating.
  • Empirically: Might be too early to tell. Her weekly “step” totals (even when considering “steps” not counted during an extra hour of battery charging) are consistent with those of the weeks before this fancy Undercover Mouse setup. This may be her initial apprehension of the toy wearing off. When she first began playing with the UM she would sit in one place and cautiously poke at the wand whenever it approached her, as seen in the video. Jennie has informed me that Snickers has gotten better at playing with the toy over the week; she will now chase, jump, and even do quasi-somersaults trying to catch the wand. Another issue that may affect the results: Often when Snickers catches the wand, she will detach it from the UM (as designed) and bat it around the basement. Jennie or I will then find it -hours later- and reattach it. This likely means that several cycles go by with no wand attached, and probably therefore little or no cat exercise going on. Hmm.

I think another week of data collection (with this fancy Undercover Mouse in isolation) is warranted before I move on to the next hilariously over-engineered cat exercise system.

Can You Light a Blowtorch with a Wimshurst Machine?


How Much Exercise Does an Indoor Cat Get?: Week Three

This is the boring/awesome engineering post.  But first, data:

2013-01-01 Snickers fitbit week three

Daily breakdowns (24 Dec to 31 Dec)


2012-12-25 to 2012-12-31 (week three) summary

Week summary (25 Dec to 31 Dec)



  • Sunday (30 Dec) was Snickers’ most active day yet, with 5477 “steps.”
  • Not much to report this week, data-wise.


  • Mondays remain the charge-the-Fitbit day, usually from 7 or 8 until 10 P.M.

Modifying An Undercover Mouse

As I said last week, I would imagine that Snickers would grow bored of her new Undercover Mouse if it were just left on 24/7, so a little modification is needed to make it turn on and off on a schedule. “Fifteen minutes on, two hours off, repeat” sounds reasonable.

I would have liked to just wire the UM up to an AC adapter, put that adapter on a simple vacation timer, and be done. Sadly though, turning on the UM is a two-stage process: 1) connect power (usually batteries) and 2) use the button on top to select a mode (Low/Medium/Fast/Random). I could have automated this process using relays and such, but at that point it would just be easier to bypass the circuit board completely and directly control the motor. Plus, direct control would allow me to tweak exactly how the toy works. Direct control it is, then.

Undercover Mouse circuit board

The guts of the UM are pretty simple: three AA batteries power a circuit board that controls a typical 5V hobby motor, which is in turn hooked to a few gears and ultimately to a little nub to which the wand attaches. After sampling the voltages across the motor leads when in use (Low = 2.4V, Medium = 2.6V, Fast = 2.7-2.8V), I snipped them from the circuit board, routed them through a convenient hole in the battery case, and soldered them to a single pair of 24 gauge wires that I pulled from an old piece of CAT5. (A note about heat shrink tube: wife’s hair dryer is apparently not hot enough, blowtorch is awesome but perhaps a bit too hot; even with an aluminum foil shield the base’s plastic was superficially dulled a bit.)

UM drive wires

I taped the wires to the floor, and ran them into a SainSmart L293D Motor Drive Shield, a preassembled version of Adafruit’s fantastic mshield. With all the messy hardware done, I then wrote a nice little Arduino program to control everything.

UM in basement

My Arduino lacks a real time clock, so we won’t be able to exactly pin activity from the Fitbit tracker to a particular session of Snickers playing with the UM. But with any luck, next week’s total activity numbers may show a slight improvement above the last three weeks of baseline.


How Much Exercise Does an Indoor Cat Get?: Week Two

 IMG_5155 copy

 Another week of baseline data and the first tests of a new toy.

Daily breakdowns (17 Dec to 24 Dec)

Daily breakdowns (17 Dec to 24 Dec)


Week summary (18 Dec to 24 Dec)

Week summary (18 Dec to 24 Dec)



  • Several people who looked at last week’s data have pointed out that Snickers seems to go nuts from about midnight to 3 A.M. The same pattern continues this week. This definitely matches up with our anecdotal experience.
  • Thursday’s daily breakdown shows what I initially thought was a swathe of pure laziness, but Thursday’s total step count is similar to that of other days. She was likely resting after an active night (of running up and down the hallway, batting cat toys beneath furniture, etc.).


  • Monday (24 Dec, at bottom) was once again charge-the-Fitbit day, this time from 8-10 P.M.
  • Though I found a wonderfully-titled paper that would help in estimating Snickers’ stride length, I am still unsure how the Fitbit tracker’s steps correlate to actual cat steps, so the distance and step numbers remain dubious.

Toy: Undercover Mouse

Snickers has a few toys already: a scratching post, a toy mouse suspended from the ceiling with elastic, and a menagerie of other stuffed fabric playthings; usually mouse-shaped and usually missing ears or appendages. For this experiment I wanted a toy that would cause a noticeable bump in measurable activity. A buddy of mine recommended an Undercover Mouse.

Snickers’ initial impressions were less than favorable, probably due to the sound of the motor.  My wife was able to gradually introduce her to it later and now she loves it. But if we just left it on 24/7 she would likely grow bored of it fairly quickly. The best way to exercise a cat with this toy may be to turn it on several times during the day and let the cat play with it long enough to burn some calories but not long enough for the cat to lose interest. If you have an erratic schedule you could theoretically do this manually, but no one has time for such things.

As soon as some new parts arrive, the engineering phase of this experiment will begin.

Undercover Mouse circuit board

Undercover Mouse circuit board that somewhat resembles a smiley face


How Much Exercise Does an Indoor Cat Get?: Week One


It has been one week since I attached a Fitbit tracker to my cat. Let’s look at the data.

Snickers fitbit week one

Daily breakdowns


Snickers fitbit week one summary

Week summary (12 Dec to 18 Dec)


A few observations:

  • Looking at the daily breakdowns, the general pattern would best be described as: “Sleep for an hour or two, goof off for a bit, repeat.” Sounds about right.
  • Some cats can sleep up to twenty hours a day, and I would have expected Snickers to be on this end of the laziness spectrum. Even if we assume that 100% of her sedentary time is spent asleep, she still would not be able to log twenty hours. At least she is less lazy than I expected.
  • When she is awake she is also much more active than I would have expected, playing for an hour or more on several occasions. Impressive.
  • Friday and Saturday evenings usually mean guests, and therefore mean that Snickers will sequester herself in the basement or beneath a bed for the duration.  This does not appear to affect her activity level.


  • Walking on four legs may confuse the tracker, so I would not trust the step count. Distance traveled is surely way off, as this is calculated from steps assuming a normal stride length for a bipedal six-foot-tall human. did not consider 9″ a valid height (nor 12.2 lbs. a valid weight) when I created Snickers’ account. Time active is probably fairly accurate.
  • I am unsure how much grooming gets picked up. Scratching around the collar may, but cat baths probably do not.
  • The tracker was removed from about 1-3 P.M. on Monday (bottom) to recharge it. Fitbit’s engineers deserve praise for designing a device that can be in absolutely constant use for over two years, and still have a 40% battery level a week after its last charge.
  • No change was made to Snickers’ daily routine, nor did we change how much we play with her. The only exception was when she had not walked near the Fitbit tracker’s wireless base station in a day or so, so I shut her in my office for five minutes to allow the tracker to connect and upload its data.  She gave me a kind of bewildered “Why am I in here?” look when I opened the door to let her out.


Snickers seems to have adjusted to the collar and Fitbit tracker fairly quickly, so now that we have a good baseline we should be able to start throwing some new cat toys into the experiment to see if they make her more active.