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FISHMANPET posted:I've definitely been Why do you only have 1 free GPIO on your Pi? It comes with like 30 of them, what are you using the other ones for? If you really want to get into the weeds you can buy a GPIO expander chip (which conveniently come on breakout boards from places like sparkfun) and then use the I2C bus + one extra pin to signal interrupts (the chip can tell you when something's changed so you don't have to sit there and poll it all the time) but I'd definitely see about doing it with just the onboard GPIO before adding more complexity...
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Feb 13, 2020 15:55
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about the best way to do this. There will be a board in the project already so I can put in a chip if I need to, though I'm not sure what putting the signal through an AND gate gets me that I don't get from just making it a single loop, in this application. It seems like even with the AND gate, you could turn one of the switches on and hold it, and then once the other one turns on the gate would activate.
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This is the project I'm building, all the other pins are taken up with all the LEDs and buttons already there. By my count the only GPIO pin that's not being used is pin 18. I can get expanders, but the GPIO library I'm usiong (gpiozero) doesn't support support expanders, so I'd have to learn a whole new way of controlling devices plugged into the expander. And the GPIOzero library doesn't really do the whole "infinite loop" paradigm so I'd have to figure out how to get the GPIO zero paradigm to intermingle with whatever I would use to support the expansion board. Though, interstingly enough, GPIOzero does support using a Pi zero over USB as an expansion board. But I'd like to avoid too much scope creep to be able to actually finish something. I guess even adding these buttons is scope creep, but my Amazon Prime addled brain is reeling at the $8 shipping for $18 of TE connectors so I'm wondering if I can put more into that order to justify the shipping cost to myself.
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Feb 13, 2020 16:26
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If you have s bunch of LEDs on their own GPIOs, you can swap that out for a shift register and that gives you more GPIOs for switches.
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Feb 13, 2020 17:22
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I don't even
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Feb 13, 2020 23:27
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Wire up a circuit to turn each switch into pulse switch, wire them in series, and then just sample it with the micro-controller. It's good to remember that you can do almost anything in analog. Even digital logic is, at its base, an analog circuit. Those old switches for launching ICBMs were assuredly purely analog circuits like this.
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Feb 13, 2020 23:50
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Stereotype posted:Wire up a circuit to turn each switch into pulse switch, wire them in series, and then just sample it with the micro-controller. OK, this is actually exactly what I was wanting to do, just not having any idea what it was called. Looking a little closer, it looks like a 555 (or 556 since I want two pulses) would do essentially the same thing?
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Feb 14, 2020 01:27
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FISHMANPET posted:OK, this is actually exactly what I was wanting to do, just not having any idea what it was called. Looking a little closer, it looks like a 555 (or 556 since I want two pulses) would do essentially the same thing? Yeah you can do it in a few ways, I haven’t actually built this stuff in a long time though. The easiest might be just the RC discharge circuit connected to a FET, but you probably have more control with a 555. I think they call it a “Monostable Oscillator” or a “one shot” or something like that, I bet there are a ton of reference circuits online. Thinking about it again, you can’t just do it in series unless you know which one is turned first, you need to generate a pulse for each switch then put them through an AND gate whose output you can sample with the microcontroller.
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Feb 14, 2020 01:56
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555 timer will do it. In monostable mode you can decide how long the pulse stays high after you turn the switch, so you won't need spring return switches. You could turn one, run to the other one and turn that one but the first one will be back to off by then. With a 100uF cap and a 10k potentiometer, you could set the pulse width from 0.01 seconds to 1.1 seconds.
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Feb 14, 2020 02:12
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Cojawfee posted:555 timer will do it. In monostable mode you can decide how long the pulse stays high after you turn the switch, so you won't need spring return switches. You could turn one, run to the other one and turn that one but the first one will be back to off by then. With a 100uF cap and a 10k potentiometer, you could set the pulse width from 0.01 seconds to 1.1 seconds. Yeah a 555 in monostable mode would be perfect for this. This article is what I use whenever I need to remember how to wire up a 555, scroll down to the "monostable" section: https://www.electronics-tutorials.ws/waveforms/555_timer.html
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Feb 14, 2020 15:58
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Anyone got some book recommendations for RF stuff?
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Feb 16, 2020 04:17
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What kind of RF? Do you just want to control everything via Bluetooth? WiFi?
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Feb 16, 2020 07:47
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brand engager posted:Anyone got some book recommendations for RF stuff?
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Feb 16, 2020 11:51
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Hey folks, This question might be stupidly simple so apologies in advance. So I'm looking at a bit of equipment (old school synthesizer) that's bust - so I've checked the fuse which is fine, electricity is going to it but its not switching on - so first point of call is the switch which is already damaged and missing parts. It had a 100k resistor and a tiny halogen bulb in it but the bulb is getting no continuity (and I have no idea how to identify or replace it but that's another matter for another time). I was guessing the switch when in the right position would just connect left to right ala the red dotted line which would also turn on the bulb. Its pretty cramped at the back but I can see 2 lives on one side and 2 ground on the other, and going by the schematic, is it meant to be connecting more like the greenish dotted line? Ideally I'd like to short the switch without killing the synth, dying and/or burning the house down.  Thanks! E: so looking at it a bit more, I think both the red and green lines should be connected - the red is just to light the bulb though? So I should be able to get away with getting the backside off, desoldering it and buying a illuminated double pole DPST rocker switch that's rated for the incoming voltage to replace it? A LOVELY LAD fucked around with this message at 23:15 on Feb 16, 2020 |
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Feb 16, 2020 16:43
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kid sinister posted:What kind of RF? Do you just want to control everything via Bluetooth? WiFi? Just overall principles. I've got "the art of electronics 2nd edition" and the arrl antenna book that go over some of them
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Feb 16, 2020 18:55
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brand engager posted:Just overall principles. I've got "the art of electronics 2nd edition" and the arrl antenna book that go over some of them If you are interested in overall principles, I would second VictualSquid's suggestion. 'Microwave Engineering' by David Pozar is a good RF book.
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Feb 16, 2020 19:09
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VictualSquid posted:Pozar's "Microwave Engineering". This is the answer, if you want a solid theoretical background and are comfortable with math. Basically necessary if you're doing any component-level circuit design at UHF or higher. If you just want to hack stuff together for ham radio setups (totally fine), stick with the ARRL stuff. ANIME AKBAR fucked around with this message at 15:16 on Feb 17, 2020 |
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Feb 17, 2020 14:07
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I am losing my mind, and coming to the conclusion that there is no way to connect these switches besides soldering to the terminals. I bought expensive TE connectors (18 cents a connector) that are perfectly sized for my terminals, they fit perfectly. Except the insulation is too big so I can't actually use the middle pin (left is C, middle is NO, right is NC, I need to connect C and NO). Might try grinding the insulation down on one side but if that doesn't work I'm just gonna say gently caress it and just bite the bullet and solder some wires on to the end. There are other connectors I could find (uninsulated connectors, some premade connector wires from adafruit, some wire harnesses that I can only buy Aliexpress) but I think I'm done wasting my money and time on trying to avoid soldering. 
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Feb 21, 2020 17:04
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FISHMANPET posted:I am losing my mind, and coming to the conclusion that there is no way to connect these switches besides soldering to the terminals. I bought expensive TE connectors (18 cents a connector) that are perfectly sized for my terminals, they fit perfectly. Except the insulation is too big so I can't actually use the middle pin (left is C, middle is NO, right is NC, I need to connect C and NO). Might try grinding the insulation down on one side but if that doesn't work I'm just gonna say gently caress it and just bite the bullet and solder some wires on to the end. There are other connectors I could find (uninsulated connectors, some premade connector wires from adafruit, some wire harnesses that I can only buy Aliexpress) but I think I'm done wasting my money and time on trying to avoid soldering. You should be able to find terminals without that bulky insulation. They'll likely be a bit cheaper, too. If you're worried about shorting, heat shrink is usually lower profile. KnifeWrench fucked around with this message at 17:16 on Feb 21, 2020 |
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Feb 21, 2020 17:13
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Make a breakout harness. Solder your wires to the plugs, solder your connecters to your wires, that way it's at least still somewhat removable. This is assuming you have male connectors as well.
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Feb 21, 2020 17:15
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Just cut the insulator off and add heatshrink instead.
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Feb 21, 2020 17:19
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Just solder it
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Feb 21, 2020 21:54
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For your typical 16/19mm automotive push button switches (the kind with cool ring-lights built in) they make special connectors like this: Maybe something like that is what you're meant to use?
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Feb 21, 2020 21:58
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I've seen those, but I'm not really sure what they're called to find places to buy them, so all I can find is getting them from Aliexpress in 1.5 months, or paying $10 a piece on Amazon. I've suspect they're an "automotive" thing but still kind of hard to find. Ok looked one more time and E-Switch appears to make them... FISHMANPET fucked around with this message at 00:27 on Feb 22, 2020 |
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Feb 22, 2020 00:22
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um excuse me posted:Make a breakout harness. Solder your wires to the plugs, solder your connecters to your wires, that way it's at least still somewhat removable. This is assuming you have male connectors as well. Yep, this is what I'd do. Then you can also get locking connectors or en-bloc keyed ones or whatever.
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Feb 22, 2020 00:34
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FISHMANPET posted:I am losing my mind, and coming to the conclusion that there is no way to connect these switches besides soldering to the terminals. I bought expensive TE connectors (18 cents a connector) that are perfectly sized for my terminals, they fit perfectly. Except the insulation is too big so I can't actually use the middle pin (left is C, middle is NO, right is NC, I need to connect C and NO). Might try grinding the insulation down on one side but if that doesn't work I'm just gonna say gently caress it and just bite the bullet and solder some wires on to the end. There are other connectors I could find (uninsulated connectors, some premade connector wires from adafruit, some wire harnesses that I can only buy Aliexpress) but I think I'm done wasting my money and time on trying to avoid soldering. Well yeah, you bought switches with solder terminals. Solder to them. That's the point of those terminals. If you want a disconnect past there, put a connector on afterwords. I like the .062 Molex stuff for ease of use. babyeatingpsychopath fucked around with this message at 00:57 on Feb 22, 2020 |
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Feb 22, 2020 00:55
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Sup
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Feb 22, 2020 01:04
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longview posted:For your typical 16/19mm automotive push button switches (the kind with cool ring-lights built in) they make special connectors like this: I've yet to find a single one of those that fits the connector pattern and size of the switch FISHMANPET has.
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Feb 22, 2020 01:17
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i want an excuse to buy a lil e-paper screen and am considering tackling a small arduino-based e-reader as the excuse; ran into this open-source design for one, and was tickled mightily by the dr bronner's-calibre tomes of text worked into the pcb silkscreen i sincerely think it's extremely cool to bake documentation like this right into the device itself, for years and years i wondered how the gently caress a circuit board can do what it does but if i'd run into sth like thsi as a kid it would have blown my mind and gotten me Extremely Engaged
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Feb 23, 2020 07:12
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Ambrose Burnside posted:i want an excuse to buy a lil e-paper screen and am considering tackling a small arduino-based e-reader as the excuse; ran into this open-source design for one, and was tickled mightily by the dr bronner's-calibre tomes of text worked into the pcb silkscreen That is hands down the coolest PCB silkscreen I’ve ever seen and now I want to do that myself
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Feb 23, 2020 07:18
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That is rad Don't link it or anything 
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Feb 23, 2020 07:19
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whoops, yeah- https://github.com/joeycastillo/The-Open-Book apparently there's an italo calvino quote hiding somewhere on the pcb but i haven't been able to find it yet Stereotype posted:That is hands down the coolest PCB silkscreen I’ve ever seen and now I want to do that myself Ambrose Burnside fucked around with this message at 08:14 on Feb 23, 2020 |
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Feb 23, 2020 07:32
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Does anyone actually have fun soldering LED strips
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Feb 23, 2020 08:25
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Do robots experience fun?
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Feb 23, 2020 08:26
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i really love this project specifically for its phenomenal ergonomics and thoughtful + efficient design http://justine-haupt.com/rotarycellphone/ i particularly like the wraparound e-ink screen, it's above and beyond the best implementation of a flexible display i've ever seen in any product. slick as poo poo form-factor, but more importantly it actually does something useful and isn't just a gimmick, i.e. the main display offers everything while device is held in the hand, edge display offers just the spark notes for quick pocket peeks   it's a breath of fresh air after the endless procession of projects heaved loosely into standard Acrylic Afterthought Discount Enclosures Ambrose Burnside fucked around with this message at 09:27 on Feb 23, 2020 |
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Feb 23, 2020 09:24
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That is an incredibly silly thing, I love it
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Feb 23, 2020 09:35
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Speaking of locking connectors, I'm looking for a crimpable connector system to move me past Duponts. Something with lock that's inexpensive, low current, common, with choice of mulitple number of positions, and suitable for wire-wire and wire-board use. Ideally a kit I can get on Amazon (or less if I wait for ebay/ali) and put in my home lab, office, and give out to students I work with. What connectors do you guys keep on your shelf?
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Feb 23, 2020 16:18
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They’re not really designed for wire-to-wire, but I keep JST XH connectors on hand by the dozens
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Feb 23, 2020 17:06
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csammis posted:They’re not really designed for wire-to-wire, but I keep JST XH connectors on hand by the dozens JST would be my recommendation as well. Different families have different pitch and locking characteristics -- I have PAs -- but they're all good quality. The catch is, I don't know how the market is for generic crimpers, and, as usual, the official ones are kind of an investment.
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Feb 23, 2020 17:23
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KnifeWrench posted:The catch is, I don't know how the market is for generic crimpers, and, as usual, the official ones are kind of an investment. I have these guys and they work pretty well for me. I’m in the low hundreds of crimps on them and they are still in good shape. The large side of the JST pin fits in the 1.9 slot and the small side in the 1.3 slot.
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Feb 23, 2020 18:23
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| # ? May 9, 2024 05:43 |
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Stabby McDamage posted:Speaking of locking connectors, I'm looking for a crimpable connector system to move me past Duponts. Something with lock that's inexpensive, low current, common, with choice of mulitple number of positions, and suitable for wire-wire and wire-board use. Ideally a kit I can get on Amazon (or less if I wait for ebay/ali) and put in my home lab, office, and give out to students I work with. Molex Micro-Fit
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Feb 23, 2020 18:44
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