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[00:04:44] <rue_house> I was pacing it
[00:05:11] <rue_house> I just sped it up, it gets pretty wiggly with its lack of rigidity
[02:11:10] <anton02> the wheel encoder generator here creates a pattern which you'd only use one of the layers of, doesnt it? It wouldnt make use of all of those layers since the ir receiver only spans about the width of one of them.
http://www.bushytails.net/~randyg/encoder/encoderwheel.html
[02:12:02] <anton02> Casper you gave me this link
[02:14:56] <Casper> there is single and multi bits encoders
[02:15:55] <anton02> Casper: whats the benefit of multi-bit?
[02:16:14] <anton02> error detection perhaps
[02:16:18] <anton02> i dont know
[02:17:11] <Casper> a simple 2 bits... the second bit can be used to tell the home position
[02:17:36] <Casper> a many bits can be used to instantaniously know the position
[02:17:49] <Casper> think of "volume button"
[02:18:09] <Casper> no need to save the position to restore on power up
[02:18:16] <anton02> i see
[02:18:46] <anton02> would that require more photointerrupters
[02:18:54] <Casper> sure
[02:19:12] <anton02> theres a 2nd image generated below the 1st. Whats that for
[02:19:13] <anton02> ?
[02:19:15] <Casper> if you don't care about the rotational position, but just a count, then 1 bit is good
[02:20:16] <Casper> photodiode masking, not sure what it is for
[02:20:50] <anton02> im going to make a wheel from balsa and cut those white sections out of the wood
[02:21:05] <anton02> then paint the wheel with black acrylic to help the IR
[02:21:19] <anton02> black acrylic = more absorbant than printed paper
[02:21:51] <Casper> depending on the size and speed, you may be able to hack an old ball mouse
[02:22:31] <anton02> already have but the encoders are annoying to lay out and allign properly
[02:23:15] <anton02> besides, cutting out pieces from the wheel is also beneficial due to lower mass moment of inertia
[02:23:54] <anton02> so the benefits are 2 fold
[02:26:08] <anton02> i will probably make one with this pattern since i only really need 1 bit
[02:26:09] <anton02> http://heliosoph.mit-links.info/wp-content/uploads/2013/06/rotary_encoder_index_disc.jpg
[02:26:34] <Casper> yeah
[02:29:25] <anton02> Casper: do you know any how tos on how to make a steering system?
[02:30:22] <anton02> a servo one, not dc motor
[02:30:47] <Casper> why not use a premade servo?
[02:31:01] <Casper> you can use a pot for the feedback too
[02:31:30] <anton02> Casper: i will use a premade one. Just need to learn how to connect it to wheels and turn it
[02:31:43] <anton02> i could probably do with just one wheel steering
[02:31:56] <anton02> it would be a 3 wheel car
[02:32:00] <anton02> in this case
[02:32:10] <Casper> there should be lots of info on that on the net
[02:32:35] <Casper> basically you link both wheels... and put the servo on that link...
[02:38:38] <Casper> nite
[02:42:00] <anton02> night
[19:43:47] <alex20032> I need some help to get an idea for a final year project
[19:46:39] <alex20032> I need something that require no manual skill (so no building thing with hammer, screw, wood....), almost no analog, mostly digital/mcu, that can have a embedded computer (beaglebone or raspi), networking, and be real time
[19:55:04] <Valen> some sort of music thing is all i can think of
[19:55:23] <Valen> generally real time implies acting on the real world which also implies doing something in it
[19:58:56] <alex20032> Also, I have another criteria... it must be something that represent the city of tomorrow
[19:59:42] <Valen> cities are kinda noted for being physical things
[20:00:21] <Valen> also when you say realtime what exactly do you mean
[20:00:26] <Valen> to us it has specific meanings
[20:13:41] <alex20032> well, by real time, i mean it could be fun for me to play with timing critical application
[20:13:49] <Roklobsta> this should be called #domyhomeworkforme
[20:14:06] <alex20032> I got a beaglebone black with PRU, so why not play with them if i could... but its not a criteria
[20:14:28] <alex20032> I dont ask to do homework for me... just helping me to get a project idea
[20:18:53] <Roklobsta> when is the project due? usually the professors will have alist of things you can do
[20:20:08] <alex20032> no list
[20:26:03] <alex20032> Well, we will start the project next january
[20:27:30] <alex20032> but we must submit project idea in september
[20:27:48] <alex20032> and i dotn want to start searching for idea last minute
[21:16:04] <Lirezh> I have a very strange problem. When I disconnect GND from an i2c slave my timer1 and timer3 values are messed up. The OCR registers change and sometimes ICR also changes.
[21:16:30] <Lirezh> in my whole project ICR is only set once during startup to a fixed value!
[21:17:03] <Lirezh> What can cause an AVR mega 128 to change values of all timers randomly
[21:17:40] <Lirezh> I output 4 PWM signals (all 4 same vaue) and I can reproduce the case that after reconnecting GND to my i2c extension all 4 PWMs are completely randomized
[21:18:40] <rue_house> all chips need to be ont eh same ground
[21:19:01] <Lirezh> sure that's the case
[21:19:25] <rue_house> you said you disconnected ground, dont.
[21:19:29] <Lirezh> The crazy thing is that everything goes BACK to normal if i reconnect ground
[21:19:40] <rue_house> yea, you need ground conneted
[21:19:59] <Lirezh> I talk about the ground of my i2c slave. how can that affect internal registers of my avr ?
[21:24:17] <Lirezh> I am aware that ground should not be disconnected but I think about the device falling down for example, the sensor slave gets damaged. it is ok if the I2C slave goes off but I need the CPU to continue ticking
[21:36:24] <Casper> Lirezh: it can cause interrupts to happend at who knows what frequency
[21:36:27] <Casper> and random data
[21:38:22] <Lirezh> hmm yea (ISR for I2C is disabled)
[21:39:01] <Lirezh> It even changes the ICR values for my timers. in my code there is no instruction to do that at all, it's meant to be static at 0x7fff.
[21:39:37] <Lirezh> I just don't get what exactly causes the AVR to change registers. no buffer overrun or similar could do that
[21:48:56] <kastein> dude just leave your ground connected. randomly disconnecting it is like taking the wheels off your car while driving it and then wondering why it doesn't keep floating along exactly in the same spot
[21:49:12] <kastein> so stop doing that
[21:55:44] <Valen> lol disconnecting ground
[21:56:02] <Valen> if you have any other pins active its going to drive everything out of range
[22:01:41] * Xark likes the car analogy. :)
[22:25:33] <rue_house> Lirezh, if your going to disconnect ground, do so with the power off
[22:25:48] <rue_house> and dont turn it back on till ground is -re-connected
