Member #134773

Member Since: May 19, 2010

Country: United States


I started playing with electronics in the mid-1960s, and with computers shortly after Neil Armstrong took “one small step”. I got a degree in CS in 1980, and started working then as an engineer.

  • Being a (now semi-retired) engineer, I tend to notice a lot of things. More than 20 years ago, I daily drove by a section of freeway that was under construction. I happened to notice that they didn’t seem to be embedding any reinforcing steel, so I asked a civil engineer friend who worked for the state Department of Transportation about it. He said that they were using a fiber reinforced concrete, and that it was stronger than the steel reinforced variety, plus because of the avoided labor in getting the steel in just the right place, it was less expensive, and it meant a few days less construction due to not having to place the reinforcing steel. Although I don’t drive that section daily any more, I do go over it a few times a year, and haven’t noticed any deterioration (caveat: freezing weather is rare in the Phoenix area).

  • I happened to think of something from when I was a young kid back in the early 60s: One of the activities at “summer bible school” one year was carving blocks of plaster with some sort of additive to make it “softer” and easier to carve (they’d been cast in the old cardboard half-gallon milk containers). I remember trying this later with ordinary plaster of paris, but because we didn’t have the additive, it was much more difficult to carve. I never did find out what the additive was (I think I was maybe 10 or 11 years old at the time).

    Anyway, plaster is a bit more amenable to post-casting modifications.

  • In Sun City, AZ, many homes have green-dyed concrete in lieu of grass…

  • For me, it brings back memories of wanting one but never getting one, also back in the 60s. (My mother also said “Legos are too expensive”, so I never had the pleasure of those as a child, either.)

  • Purists will point out that there are differences between cement, concrete, grout, and mortar, though they can be somewhat abstract (had to get that pun in somehow!), though all four are related. What you have is technically a grout. One word of caution: do NOT try using “hydraulic cement” – it is meant for things like repairing cracks in swimming pools, and it expands as it cures. (It could crush the electronics.)

    One idea that occurs to me is to cast “project boxes” – boxes with space for the electronics to be installed later. You can cast in threaded inserts for screws to mount the boards and/or assemble the boxes later.

    As for molds, yes, you can use “off the shelf” stuff, or explore “making your own”, hand crafted, 3-D printed, vacuum formed, CNC milled, etc. (A thought about cardboard molds: rather than using “plain old cardboard”, use some of that plastic coated stuff that frozen foods often come in – it should be more immune to the moisture from the material being cast.)

    One last thought: I’ve found concrete to be a fascinating material. The Army Corps of Engineers published a handbook on the stuff several decades ago, at it can make interesting reading. Sorry, I don’t have my copy handy, so can’t give you the exact title. (I got my copy well before Mary was born, but I’d be very surprised if you can’t find a copy today.)

  • In your Arduino code, you have defined “int pot = A0;”, and used it in the pinMode() call, but in the analogRead() call you go back to hard-wiring A0.

    The whole point of defining an “alias” (BTW, it’s usually better to use “#define pot A0” so it doesn’t accidentally change value, or maybe make it a constant) is so that if you at some point have to change it to, say, A1, you don’t have to go through the whole program looking for A0, you just change it in one place. (Also, with having them defined at the top of the program you can, at a glance, see which pins are actually used and thus, which are still available.) True, in this very short program it really doesn’t make much difference, but when you get to the point where you have 1837 lines of code to go through, it sure helps!

  • … your girlfriend asks what you want for your birthday, and you respond with “Adafruit’s 10-color assortments of stranded and solid hookup wire” and then hope that it’ll last to Christmas.

    … you’re disappointed when a gift says (only) some assembly required.

    … you keep coming up with more responses to this question.

  • … you use the closest (of many) wire cutters to trim your fingernails or toenails.

    … you make nearly half the replies to your own posts on Sparkfun’s blog.

  • … no room for meals on the dining room table, OR the kitchen counters!

    … you have a soldering station and good parts supply under your “significant other’s” bed “just in case you need them”.

    … your on-line ads are from Digi-Key, Arrow, and Element 14.

  • I’m a bit nervous about a LiPo on someone’s head, too, especially a child’s head. As an alternative, check out the 3xAAA holder from Adafruit. If you use it for the “Beginner” LED-only headband you ABSOLUTELY have to include a current limiting resistor in series, but if you use it for the “Advanced” computerized version, just replace the two LiPo batteries with it. BTW, I’ve built several projects involving ProMini computers and some addressable LEDs and they worked just fine running on 3 AAA cells. The only “downsides” are that the battery holder and batteries weigh more than a LiPo, and you’re using “disposable” batteries.

No public wish lists :(