Olin Lathrop

838 reputation

bio	website	embedinc.com/olin
	location	Littleton, Massachusetts
	age	56
visits	member for	4 months
	seen	10 hours ago
stats	profile views	82

Electrical engineering consultant specializing in microcontrollers and the circuitry around them. Master of engineering in EE from Rensselaer Polytechnic Institute in 1980.

We are certified Microchip design partners, and have been in the top catagory consistantly since around 2000. Various free downloads related to developing PIC firmware and other things are available at http://www.embedinc.com/pic/dload.htm.

	838 reputation	bio	website	embedinc.com/olin	visits	member for	4 months
9 badges		location	Littleton, Massachusetts		seen	10 hours ago

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1d	comment	How big of a telescope to view Gliese 581g in great detail? To put this in a different perspective, that's about 160 miles in diameter, which if placed on Massachusetts would be a dish extending from Boston to the New York border. Get your grant application in now!
1d	comment	Why does asphalt crack along painted lines? I don't know the details. I remember noticing the issue on I-495 and mentioning it to a friend, and he said there was a Boston Globe article on it recently. That was probably a couple of years ago. What I reported was heresay from the friend who claims to have read the article, but I have no reason to suspect he wasn't reporting what he believed to be true. I've probably given enough details that some quality time with Google or Bing can uncover the story.
1d	answered	Why does asphalt crack along painted lines?
2d	answered	Tension in parallel springs
2d	comment	Energy of a cylinder rolling down a path In this special case you don't need to look up the moment of inertia. You can see from insection that the speed of the mass in the shell due to rotation is the same as that due to translation. Therefore half the energy is in rotation, which doesn't add to the cylinder's speed. Half the energy means sqrt(2) less speed.
2d	answered	Magnitude of force to keep stick in equilibrium
Jun 14	comment	Why two connected 1.5 volt battery become 3 volt @Signus: The internal resistance has no effect on the open circuit voltage. It causes lower voltage when current is drawn, but no more so per battery as when they are by themselves. If the internal resistance is 2 Ohms and you draw 300 mA, then each battery will drop by 600 mV. If the open circuit voltage was 1.5 V, then there will be 900 mV accross each battery. That still doubles when you put two such batteries in series, which gets you 1.8 V total at 300 mA.
Jun 14	answered	Why two connected 1.5 volt battery become 3 volt
Jun 9	comment	Buoyancy Problem - Cubes in water @Kamira: If you are considering dynamic effects like inertia, then the cube could penetrate a little bit. In reality I think the inertia will be small relative to the friction, so very little of that will happen.
Jun 8	comment	Buoyancy Problem - Cubes in water @Kamira: No need to be defensive. I didn't say you were trying to make a free energy machine, just pointing out that this concept comes up regularly in that context. No, the bottom cube won't penetrate at all. The force pulling it up by the rope will never exceed the force of the full water column pressing on its top surface. If these weren't cubes but tapered instead, then the bottom object would penetrate the seal partly until its cross sectional area times the water column pressure ballanced the upward pull on the rope.
Jun 8	answered	Buoyancy Problem - Cubes in water
Jun 5	comment	Is there any technique by which we can increse the speed of a car using the weight of the passenger in a car or bus? @dmckee: No, driving downhill doesn't utilize the weight of the passengers to go faster. The accelleration due to going down a hill is the same regardless of the total mass in the vehicle. The extra mass does help against non-linear friction, like air resistance, but that level of detail is not implied by your simple statement.
Jun 5	comment	GPS Working Principle The answer is C. The receiver measures the relative time between satellites, which is why it needs 4 instead of 3 to solve the simultaneous equations. It also knows where the satellites are. The orbits are fairly predictable, and the small perturbations are measured and also broadcast by the satelites in something called the "ephemeral" data. You can go even further and compare your received data to that received at a known nearby location. All these tricks are used in real units to various degrees.
Jun 5	comment	Is there any technique by which we can increse the speed of a car using the weight of the passenger in a car or bus? You can momentarily increase the forward speed by having all the passengers jump backwards, but that increased speed goes away again as soon as the passengers stop moving relative to the bus. As John suggests, shooting the passengers out the back would work, although I think a large slingshot would be easier to rig than a cannon.
Jun 5	comment	How much torque does it take to turn a doorknob? @Rody: Of course I could have done the conversion, but I was expressing the value in the form easiest for me. You convert if you want it in different units. Also it was worth writing the comment because of your holier-than-though arrogant attitude. Your "let me google that for you" link is rude and really uncalled for.
Jun 4	comment	How much torque does it take to turn a doorknob? @Rody: No, I'm going to use whatever I am comfortable with and convert as necessary to whatever I think is relevant at the time. Personally, I have a reasonable sense of what a pound is, but no such sense for a Newton without doing the conversion. The OP didn't specify units, so inch-pounds, foot-pounds, Newton-meters, or slug-fathom-furlongs per fortnight-squared are all valid.
Jun 3	comment	How much torque does it take to turn a doorknob? That sounds high. I'm guessing less for most ordinary door knobs. Imagine the outer diameter of the knob is 1.5 to 2 inches from the center, do you really think you exert more than 1 pound turning force at that radius?
Jun 3	awarded	Critic
Jun 3	awarded	Nice Answer
Jun 2	answered	Can a hybrid vehicle ever be more efficient than a hydrocarbon-only vehicle built with the same parts?