President Reagan’s Exercise Routine





President Reagan advocates fitness in 1983:





A Kickstarter Success

Inspired by Scott Locklin’s series of posts criticizing awful Kickstarter projects, I would like to share my thoughts on the Thermodo.

I first noticed this project when I followed a link from Hacker News to this article praising a successful fundraising drive by a company called Robocat. We learn that “They hit their campaign goal in just a few hours, and have raised around $270K so far,” and that they “did our best to estimate the cost of production before we started.”

Robocat is no slouch in the marketing department:

We brought with us a lot of experience from marketing our own apps and worked diligently on presenting the story in clear and concise way. We have a lot of the resources in house and produced everything ourselves, from the graphics to the video.

I’ll say.

They also needed to be cautious when choosing their fundraising goals:

We meticulously calculated the various cost factors in developing, producing and bringing Thermodo into the world. There are so many factors in the supply chain that all need to be accounted for.

How did they do?

Luckily backers blew right through that initial goal, and we now have more options.


So what is this project about?

In 2011 Robocat, a group of Danish iPhone application developers, released an iPhone “thermometer app” that displays the current temperature of the nearest compatible weather station to the phone’s user. Some users didn’t realize that this thermometer application was not an actual thermometer and couldn’t actually measure temperature, and these users rightly complained. Apparently, the iPhone doesn’t include a temperature sensor.

Not shrinking from a challenge, Robocat decided to jump into the hardware sector and to develop a thermometer for the iPhone, and to raise funds for its development on Kickstarter.

Behold, a thermometer for your iPhone:

Thermodo CAD drawing.

Computers these days–it almost looks like a real object.


How does it work?

Thermodo consists of a passive temperature sensor built into a standard 4 pole audio jack enclosed by a sturdy housing. This allows your mobile device to read Thermodo’s temperature straight from the audio input. Thermodo sends an audio signal through the temperature sensor. This sensor will then attenuate the signal amplitude depending on the actual temperature. This attenuation can now be detected on the microphone input and through software we calculate the corresponding temperature.

Really? You know what that sounds like? A voltage divider with a thermistor:


You don’t even need all four terminals.

Observe that this diagram contains 2 components: a resistor and a thermistor. This circuit does what Robocat claims the Thermodo does. Well, you need a headphone jack too, and you need to solder it.

Easy peasy! We call this the Thermodo Principle™

An easy peasy two hundred seventy thousand dollars!

Well, the product’s backers are getting an actual item that they don’t have to solder. Will it work? I am pretty sure the thing will be able to measure temperature. It would be pretty tough to screw that up. But my first thought when reading about it was the thermometer’s settling time. How quickly will it settle to the correct temperature? Robocat plans to encase the sensor in aluminum in order to improve the response time.

There’s no difference in accuracy. Both uses the same temperature sensor. Aluminum will be more sturdy and responsive to temperature changes.

So the question reduces to how quickly a block of aluminum can change temperature in air. I don’t know how many Kickstarter backers have made it through a college heat transfer course (my guess for this project is 0), but I have taken such a course. Here’s a simple differential equation describing the heating rate of a solid material, assuming the entire block has a uniform internal temperature:

\frac{d\Delta T}{dt}=\frac{\Delta T }{\frac{mC}{hA}}

This means that the thermometer settles like a first order system, entirely dependent on the time constant \tau = \frac{mC}{hA}.

T_{measured} = T_{air} - (T_{air}-T_{pocket})e^{-\frac{t}{\tau}}

We can estimate these terms from the Thermodo promotional materials. It appears to be an aluminum cylinder with a diameter equal to that of an iPhone, 7.6mm and height about 1.5 times that amount. Let’s be generous and say it’s 10mm tall and 7.5 mm across. That gives it an exposed surface area of A = 2.8cm^{2} and a mass of m = 1.2g. The specific heat of aluminum is C = 0.9 \frac{J}{gK} . The coefficient of convective heat transfer of aluminum depends on the type of convection and the surface features of the metal. It ranges from 5 \frac{W}{m^{2}K} to 200 \frac{W}{m^{2}K}. That gives us a time constant ranging from 19 seconds in forced convection to 771 seconds in quiescent air, which means that the sensor gets 63% more accurate every 19 to 771 seconds!

So what happens when you take your Thermodo from your pocket (approx. 90°F and put it in the air on a brisk morning, approx. 50°F)?

Thermometer settling curve.

Every thermometer in the world basically acts like this.

Controls engineers conventionally define the settling time of a 1st-order system to be 4 time constants (this gets your error down to 2% of the initial error). So for our most optimistic scenario, you only need to hold your iPhone out in the air for a minute to get an accurate reading, as long as you can handle the gale-force winds. It will also settle quickly if you blow on it, or shake it around. Are you still wondering why Apple didn’t include a temperature sensor on the iPhone?

My diagnosis: a bunch of software geeks attempted to create a hardware project without knowing anything about heat transfer or the theory behind sensors and got in over their heads. I bet they haven’t even tested a prototype yet. But at least they got hundreds of thousands of dollars from people who just wanted a thermometer to tell them how the air feels where they are.

Nevertheless, this is a Kickstarter success.

Edit: Who am I, you ask? I’m not much of a blogger, but I saw this silly kickstarter project and couldn’t find any criticism of it on the internet. What are my credentials? It doesn’t matter. The analysis should stand on its own.


Old Fashioned


Travel workouts

I got this list from here.

  1. Run 1/2 mile 50 air squats – 3 rounds.
  2. 10 push-ups 10 sit ups 10 squats – 10 rounds.
  3. 200 air squats for time.
  4. “Susan” Run 200m 10 squats 10 push ups 5 rounds.
  5. Sprint 200m and do 25 push ups, 3 rounds.
  6. 10 Handstand push ups and a 200m run 3 rounds.
  7. Tabata squats and tabata pushups.
  8. 5 push ups 5 squats 5 sit ups, 20 rounds.
  9. Walk 100 meters on your hands, even if it is 2 meters at a time.
  10. 10-9-8-7-6-5-4-3-2-1 sets of sit-ups and a 100 meter sprint between each set.
  11. Invisible Fran…21-15-9 of air squats and push ups for time.
  12. Spend a total of 5 minutes in a handstand, or headstand. If you are using the headstand do not stay over a minute at a time.
  13. Run 1 mile for time.
  14. 10 push ups 10 air squats and 10 sit ups, 6 rounds for time.
  15. Do one air squat and take one breath, ( you can breath all you want while you do the squat or squats) do 2 and take 2 breaths etc…up to 10, and then come back down to one.
  16. 3 vertical jumps 3 squats 3 long jumps – 5 rounds.
  17. Handstand 30 seconds and 10 squats, 8 rounds.
  18. 10 push-ups 100M dash 10x.
  19. Tabata squats.
  20. 5x 400M sprints.
  21. 10 X 100 m dash.
  22. 25 pressing snatch balances each arm. No weight.
  23. Run 1 mile, lunging 30 steps every 1 minute.
  24. handstand 30 seconds and 20 air squats, 5 rounds.
  25. 10 handstand jackknife to vertical jump, 10 handstand jackknife to tuck jump, 10 handstand jackknife to straddle jump.
  26. 100 air squats. For time.
  27. 4x 25 jumping squats
  28. 10 vertical jumps, 10 push ups, 10 sit ups, 4 rounds…for time.
  29. 10 air squats every 1 minute of your 1 mile run.
  30. 100 burpies for time.
  31. Run 1 mile for time.
  32. 10 push-ups 10 squats 10 sit ups 10 rounds.
  33. 10 vertical jumps, run 400 meters, 5 rounds.
  34. spend a total of 3 minutes in a handstand.
  35. 100 air squats for time.
  36. Handstand 1 minute, hold bottom of the squat for 1 minute, 5 rounds.
  37. Sprint 100 meters, Walk 100 meters, 10 rounds.
  38. 100 push ups for time.
  39. Run 1 mile for time.
  40. 10-9-8-7-6-5-4-3-2-1 Burpies and Sit ups.
  41. 50 sit-ups, 400 meter run or sprint or walk. 3 rounds.
  42. 10 walking lunges, 10 push-ups, 10 rounds.
  43. Tabata Squats.
  44. 50 split jumps for time.
  45. Workout…Handstand for 30 seconds or 5 handstand push ups…400 meter run. 4 rounds.
  46. 10 burpies, 100meter sprint 10x for time.
  47. “L” sit off the floor. 10 rounds of 10 seconds…if you can’t do it sit with your legs straight out and try to lift your heels of the ground for 10 seconds instead!!!
  48. run 400 meters, 50 air squats. 4rounds.
  49. handstand 30 seconds, to squat hold 30 seconds. 10 rounds.
  50. Ten vertical jumps ( jump as high as you can, land and do it again), 10 push-ups 5 rounds.
  51. Run 1 mile for time.
  52. 10 push-ups, 10 squats, 10 rounds.
  53. Tabata Squats: 20 seconds on 10 seconds rest, 8 rounds. Count your lowest score.
  54. Handstand to Jack-Knife to vertical jump. 30 Reps.
  55. Run 1 mile with 100 air squats at midpoint, for time.
  56. 7 squats, 7 burpies, seven rounds, for time.
  57. 10x 30 second handstand to 30 second bottom of the squat hold.
  58. Burpee to the push up position, do 10 push ups, burpie out. 5 rounds.
  59. Run 1 mile, plus 50 squats-for time.
  60. 100 burpies for time.
  61. 5 squats, 5 push-ups, 5 sit ups, 20 rounds.
  62. Plebs plank, bottom of squat, hollow rock hold, 30 seconds each for 10 rounds. Use the transition times as your rest periods…they should be as brief as possible.
  63. 5 push ups with a 30 second plebs plank(a hold at the top of the push up, arms extended and body tight like a plank!) at the end of each 5 reps, 10 rounds. Then 3x 100m dash @ 80%.
  64. Handstand practice, 25 tries at free handstands, then a 1 mile run at 80%.
  65. Handstand 10 seconds jack-knife to vertical jump. 25 reps…
  66. Mime 4x 25 sumo deadlift high pulls, make them perfect. Be sure the hips extend before the arms bend!
  67. 50 air squats x 5. Rest equal amounts as it took to do each 50.
  68. Run 1 mile and do 10 push-ups every 1 minute.
  69. sprint 100m 30 squats…8 rounds.
  70. 30 push ups, 30 second handstand or Plebs Plank..3 rounds.
  71. 10 sit ups and 10 burpies…10 rounds-for time.
  72. handstand hold, 30 seconds, squat hold 30 seconds…10 rounds.
  73. 250 jumping jacks…for time.
  74. 100 jumping jacks, 75 air squats, 50 push ups, 25 burpies. For time.
  75. Tabata Push-ups.
  76. 30 second handstand against a wall, followed by a 30 second static hold at the bottom of the squat. 5 rounds.
  77. with eyes closed do 10 air squats, open 10 push ups eyes closed, 5 rounds for time.
  78. Run 1 minute, squat 1 minute 5 rounds.
  79. run 1 mile for time.
  80. air squat x 10 push up x 10 sit up x 10 3 rounds for time
  81. 10 push-ups, 10 hollow rocks, run 200 meters….5 rounds.
  82. Do Tabata Squats with eyes closed.
  83. bottom to bottom ( rest at the bottom of the squat instead of standing….without support on your hands or butt and make the bottom good, straight back, butt back)…..tabata squats.
  84. 20 sit ups with support under the lumbar spine, 20 push ups, run 400m, 4 rounds.
  85. Handstands, 30 second hold, 30 second static squat, 30 second rest, 8 rounds.
  86. sprint 50 meters, 10 push ups. 10 rounds.
  87. 50 air squats, 4 rounds. rest for 2 minutes between rounds.
  88. 3x 20 tuck jumps. 3x 30 second handstands.
  89. 400m run/sprint 30 air squats, 3rounds for time.
  90. 20 jumping jacks, 20 burpies, 20 air squats…3 rounds
  91. Warm up. Run 100 meters and do 20 air squats. 10 rounds.
  92. Handstand 5x 30 seconds. Run: 2x 800 meters for time. Do the handstands first. Rest and recover and do the runs with a rest in between that is as long as it took you to run your first 800.
  93. 100 air squats 3 min. rest, 100 air squats.
  94. Run with high knees for 15 seconds and drop into a pushup, get back up and run with high knees again for 15 seconds…….repeat 5x. Each pushup counts as 1 rep. Rest. Do 3 more rounds.
  95. 10x 50 meter sprint.
  96. Test yourself on a max set of push ups…tight body chest to the floor…full extension!
  97. If you cannot do “mens style” do your pushups from the knees. After that do 100 air squats for time.
  98. Tabata…20 seconds on 10 second rest 8 rounds of…tuck jumps and then sit ups
  99. run 400m air squat 30 hand stand 30 seconds 3 rounds for time
  100. 5 handstand to jacknife to high jump, 5 handstand to jacknife to tuck jump, 5 handstand to jacknife to split jump, 3 rounds…for form
  101. 50 burpies for time.
  102. 5 pushups, 5 squats, 5 sit-ups – 20 rounds
  103. Run 1 mile, stopping every minute to do 20 air squats.
  104. 30 second handstand, 60 second squat hold ( at the bottom of the squat) – 5 rounds
  105. run 200 meters, 50 squats, 3 rounds
  106. Tabata Squats
  107. Air squatsx20, Burpiesx20, Push-Upsx20 – 3 rounds…for time.

A cat.