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[00:32:02] <pokmo> hi
[00:32:26] <pokmo> does anyone know if if there's a frictionless way for braking a metal roller?
[00:32:46] <pokmo> something like
https://floatbizimages.s3.amazonaws.com/actual/56f8ae4d9ec6680ac81a483a.jpg
[01:17:47] <z64555> hm. why must it be frictionless?
[01:17:55] <z64555> concerns on heat, debris?
[01:51:20] <pokmo> z64555, well because the ball is lubricated
[01:52:04] <pokmo> so i'm hoping to not having to rub off the lube
[01:52:10] <z64555> hm, yeah I can't think of anything that can brake a ball whell like that
[01:52:50] <z64555> was thinking maybe a solenoid to press it up against the side of its housing or whatever its called
[01:53:04] <z64555> but, I haven't seen anything like that commercially available
[01:53:35] <z64555> you might have to make the braking mechanism seperate
[01:54:03] <pokmo> z64555, you mean press the ball against the housing?
[01:54:17] <pokmo> but it's already against the housing
[01:54:32] <pokmo> i'd assume, at least
[01:55:51] <z64555> the coifienct of friction would be the same, but you'd effectively increase the weight of the ball
[01:56:17] <z64555> friction is determined by the normal force of an object vs. a surface, if that normal force is higher, you have more frictional force
[01:56:40] <z64555> and since this is inside the housing, the lube (theoritically) won't go anywhere
[01:56:47] * z64555 notes his spelling has declined
[01:57:00] <z64555> *coefficient
[01:57:19] <z64555> this is what I get for multitasking. sigh
[01:58:41] <pokmo> z64555, but say if i have a solenoid that presses a piece of rubber pad against the ball, the pad could rub off some of the lube, right
[01:59:17] <z64555> yes, but in the mechnism I was describing, the solenoid would magnetise the ball itself
[02:00:39] <pokmo> z64555, so you mean, let the solenoid push the ball against the inside of the housing to increase the normal force
[02:00:48] <pokmo> the ball is pretty well lubed, the friction is quite low
[02:03:16] <pokmo> i'm not sure if the solenoid would be able to apply enough force to significantly increase the ball's effective weight
[02:03:16] <z64555> Yeah, I'm not expecting a whole lot of braking friction with this
[02:03:33] <pokmo> i was thinking of eddy current
[02:03:54] <pokmo> switch on a electromagnet and slow it down
[02:04:06] <pokmo> but i've tried sticking a permanent magnet near it, but i can't feel any resistance
[02:04:17] <pokmo> the ball should be made out of steel
[02:04:25] <pokmo> probably because of steel's poor conductivity?
[02:04:32] <z64555> need to be an alternating current to generate eddies
[02:05:05] <z64555> you can do it with a permanent magnet, but the ball would have to be spinning quite fast for it to have any noticable effect
[02:05:21] <pokmo> right. it's only going at <60rpm
[02:06:18] <z64555> also, the fact that it's a ball means you're not going to get much in the way of eddy currents, either
[02:06:41] <pokmo> z64555, the demos i've seen all seem to use flat surfaces
[02:07:17] <z64555> right, preditable flow of eddies
[02:07:47] <z64555> you have a flat, linear surface where the eddies can make a back-emf to counter the magentic field
[02:07:51] <pokmo> so, friction is my friend, i'm guessing
[02:08:15] <z64555> I'd honestly try seperating the braking mechanism to something other than a ball
[02:08:56] <pokmo> z64555, what do you mean by separating?
[02:09:29] <z64555> like, use a caster, or another wheel to do the braking
[02:09:37] <pokmo> well, it's going to be a separate mechanism because the ball roller i have is something i got off ebay
[02:11:49] <pokmo> z64555, but how about pushing a piece of rubber against the ball roller?
[02:11:59] <pokmo> that'd be a separate mechanism
[02:12:30] <pokmo> how do you brake a ball with a caster?
[02:13:03] <z64555> by braking on the surface the ball is rolling
[02:14:12] <pokmo> but a ball is multi-directional whilst a caster has an axis of rotation
[02:20:26] <pokmo> i must be missing something
[02:48:39] <z64555> Is the ball contacting any surface?
[02:48:48] <z64555> or is it just free-wheeling
[02:49:03] <Jak_o_Shadows> Why not just push a brake pad against something else?
[03:14:00] <z64555> that's what I was trying to get at in the end
[05:03:09] <Jak_o_Shadows> Hmm. What would be a good physical sensor choice to make a mouse scroll wheel?
[05:03:22] <Jak_o_Shadows> Or heck, some sort of encodeder distance thing.
[05:03:29] <Jak_o_Shadows> I'm thinking a cheap ebay flow meter
[05:03:31] <SpeedEvil> optrical quadrature
[05:04:46] <Jak_o_Shadows> I'm sorta hoping for something pretty much a module I can drop in
[05:05:21] <Jak_o_Shadows> Like you can with the little analog joysticks you can get
[16:26:30] <theBear> rue_house, "This accepted makes the two attrition affairs of the afterglow tube in, so the mercury evaporates into the tube and the electron discharge is simplified. Ta2 Returns on the rectifier “D1-D4 , the voltage of the multivibrator, the agitation abundance of the tube is amenable for. The acceleration of the AMV is with potentiometer P1 set. The beating afresh passes through R3 to T3, is amplified there and controls the bent for the triac, th
[16:26:31] <theBear> e administering of these alternates. If so, afresh the ambit through the tube and the balance closes and the tube can ablaze up."
https://circuitschematicelectronics.blogspot.com/2012/04/40-watt-fluorescent-lamps-diagram.html
[22:50:58] <Jak_o_Shadows> rue, did you end up getting those pressure sensors? Have they arrived yet?
[22:52:13] <rue_shop5> i got them
[22:52:19] <rue_shop5> i took one apart
[22:52:23] <rue_shop5> far as i got
[22:52:35] <rue_shop5> (no internal magic serial port)
[22:56:24] <Jak_o_Shadows> ah, damn
[22:56:35] <Jak_o_Shadows> that makes things a lot harder
[22:56:51] <rue_shop5> not all so much
[22:57:13] <rue_shop5> I bought a bunch of wheatstone force sensor amps/digitizers
[22:57:24] <Jak_o_Shadows> Well, serial you just connect wires, decode whatever crazy thing they're using, then you're good.
[22:57:27] <rue_shop5> it turns out, its a wheatstone in there
[22:57:30] <Jak_o_Shadows> This way you actually gotta do work.
[22:57:31] <Jak_o_Shadows> nice
[22:57:42] <Jak_o_Shadows> So you can just go straight to an ADC?
[22:57:45] <rue_shop5> I have to probe some voltages
[22:57:47] <rue_shop5> no
[22:57:54] <rue_shop5> I have some baords
[23:00:46] <rue_shop5> http://www.aliexpress.com/item/HX711-Module-Weighing-Sensor-Dedicated-AD-Module-For-Arduino-Free-Shipping-50PCS-LOT/32228651474.html
[23:00:59] <rue_shop5> BUT
[23:01:34] <rue_shop5> I realized that with a capacitor made with a blob of silicone that has infused air bubbles, and a 555, I may be able to just make a pressure sensor
[23:03:43] <Jak_o_Shadows> Oh yeah.
[23:05:56] <rue_shop5> I think if I take 2 syringes and push some silicone back and forth between them with an air bubble, it'll get all mixed in
[23:07:15] <rue_shop5> the official sensors have to be zero calibrated on startup anyhow
[23:33:42] <z64555> rue_shop: Whats wrong with graphite? they sell them in tubes as a dry lube
[23:55:41] <rue_shop5> hu?
[23:57:55] <rue_shop5> I think I need to break the cables out of the forearm about a foot before the wrist
