# Quantumdust

1
Built my first radio when I was 10, Continued like fireworks bursting into universal physics.
• The physics and electrical connections are essentially correct. The project is useless. You obviously have an interest in electronic design. Combine that interest with the time it took to assemble the "circuit" upload the pictures and text to all the various places and you will have enough time to design something interesting and teachable to people actually wanting to make something new that they can be proud to show their friends. Skip the stuff that works for a few minutes and starts a fire.

• Quantumdust commented on djpolymath's instructable Center Finder Jig

I needed one of these since about 50 years ago. What took you so long ? :-)

• I'm very 'fuzzy' about the point and subject of your memorable text.......

• Hey Ed, I'm not trying to be a pain, it's just that after 40+ years in sensor R&D I've developed a few items (I call them my "sweet spots") that will bug me forever. You seem to be one of these very rare people these days that actually understand the math and physics behind what they think they know about. Using today's newest buzzword, " having said that" , the answer to the discussion is that we're both right. The rotational reference frame is the key to the whole thing. Centrifugal is only both fictitious and a reaction force in an inertial frame. Putting yourself in a rotating frame makes the math easier and generates the need for existence of the otherwise fictitious forces to make the analysis work. This silly discussion has been turned over and over …

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Hey Ed, I'm not trying to be a pain, it's just that after 40+ years in sensor R&D I've developed a few items (I call them my "sweet spots") that will bug me forever. You seem to be one of these very rare people these days that actually understand the math and physics behind what they think they know about. Using today's newest buzzword, " having said that" , the answer to the discussion is that we're both right. The rotational reference frame is the key to the whole thing. Centrifugal is only both fictitious and a reaction force in an inertial frame. Putting yourself in a rotating frame makes the math easier and generates the need for existence of the otherwise fictitious forces to make the analysis work. This silly discussion has been turned over and over a million times over the last thousand years by people way smarter than both of us and, depending on what "FRAME-of-mind" you are in, the discussion will persist ad-infinitum.If you need both a good night's sleep or stay awake forever :-) , read the text in the Wikipedia link here: https://en.wikipedia.org/wiki/Centrifugal_forceVlad

• Great project! Love your lab. Based on the photos and video, you really seem to be talented and know what you're doing (rare). Reminds me of my setup about 50 years ago when I started designing projects. All with vacuum tubes, and I was happy as a bunny when the first transistor was actually available for buying. One small comment re one of your descriptions (think about it and the physics will make perfect sense):You say when talking about gluing the magnets "then a magnet might fly off due to centrifugal force, also known as tangential velocity". What really happens if the glue lets go is the magnet flies off " in the direction of the instantaneous tangential velocity". The glue exerts a centripetal force on the magnet keeping it locked going toward the cen…

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Great project! Love your lab. Based on the photos and video, you really seem to be talented and know what you're doing (rare). Reminds me of my setup about 50 years ago when I started designing projects. All with vacuum tubes, and I was happy as a bunny when the first transistor was actually available for buying. One small comment re one of your descriptions (think about it and the physics will make perfect sense):You say when talking about gluing the magnets "then a magnet might fly off due to centrifugal force, also known as tangential velocity". What really happens if the glue lets go is the magnet flies off " in the direction of the instantaneous tangential velocity". The glue exerts a centripetal force on the magnet keeping it locked going toward the centre of the spinning system. Centrifugal force is a fictitious never-ending historical misunderstanding. If the glue breaks the magnet travels, as you say correctly, tangentially. If centrifugal was real, the magnet would fly in a radial direction outward. Never happens, try it!

• be safe and sell your car.....

• Two comments. The LED connection is not shown in the schematics. In #3, where is the connection that charges the battery from the solar cell?

• Quantumdust commented on lkndave's instructable Remote Control Update

Good stuff. Easy fix and, yes, it works much better.

• The circuit does work and is about 100 (give or take) years old.It is good for teaching people that are not familiar with the LM317 how to make it variable. I would strongly suggest, to make the schematic logically obvious, put the input on the left with the +ve on top, -ve (ground) on the bottom and the output on the right, +ve on top, referenced to ground. R1 simply goes from Adj. pin to ground in the middle. Much nicer on the eyes.

• Two seconds of keystrokes on Google gives instant answers to a LOT of obvious questions that people ask on Instructables :-)Wikipedia: Hydroxy gas: A nickname for oxyhydrogen, a combination of hydrogen and oxygen gas produced from the electrolysis of water

If you don't provide separate containers for the two products evolved you get a mixture in one container. This is obviously what the designer wants from the start. Try reading his description again.

• LiPo cells for RC flyers, unless they already have manufactured connections, probably have metal (sometimes Aluminium) tabs that are more forgiving than soldering directly to the battery cases of 18650 and other sizes. Still, LiPo absolute max temperature is rated at 140F/60C. After that they become unstable and a fire hazard.For the record, I've soldered Li-Ion 18650 cells once or twice and got away with it without calling the fire department. Then I did a little study on the chemistry and construction of Li batteries in general. Most people don't take the time to dig into this stuff and simply think that batteries are batteries and some are better than others. Not so. Ask the guys that bought electric skateboards only to have them catch fire under them with only "normal"…

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LiPo cells for RC flyers, unless they already have manufactured connections, probably have metal (sometimes Aluminium) tabs that are more forgiving than soldering directly to the battery cases of 18650 and other sizes. Still, LiPo absolute max temperature is rated at 140F/60C. After that they become unstable and a fire hazard.For the record, I've soldered Li-Ion 18650 cells once or twice and got away with it without calling the fire department. Then I did a little study on the chemistry and construction of Li batteries in general. Most people don't take the time to dig into this stuff and simply think that batteries are batteries and some are better than others. Not so. Ask the guys that bought electric skateboards only to have them catch fire under them with only "normal" use.

• Ideas are good....just a couple of comments. Make sure that you, and especially your kids if they are doing it, are very careful cutting the jacket of the old battery. The chemicals inside are NOT user-friendly and can be nasty or toxic if spilled out.The second not is do NOT EVER solder to Li-Ion batteries with a soldering iron. These cells are not meant to be heated like that. Links are always attached with a spot-welder which does not invade the internals of the cell. If you heat it with solder you may be lucky and nothing will happen except a soldered connection, if you are unlucky you get a thing called thermal runaway where the battery shorts inside, heats up, emits hazardous fumes, catches fire and potentially explodes. Unless you like calling 911, do not do this.