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A proportional solenoid valve is what you want to google for, though they tend to be quite expensive. A cheaper solution would probably be to rig a servo onto a traditional gas knob/dial
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Feb 11, 2017 17:02
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Yeah, either a servo or a geared stepper motor with a limit switch connected to a regular valve would be the cheapest way. Goes without saying that if this is controlling a natural gas line and you aren't a certified gas fitter, please stop and do not do whatever it is you're planning
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Feb 11, 2017 19:17
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Dude I'm in building controls and you already scared the poo poo out of me. I could help you but I won't. Why don't you call your gas or propane provider and ask them for recommendations, since you don't even know what to google for you should not not not be anywhere near that stuff... Especially when you're combining it with hobbyist-level electronics. Like, you could very well get charged with terrorism-level charges if someone finds out you're loving with stuff like pressurized gas and electronics - lord forbid you're connected to the grid and not just a 1 lb tank.
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Feb 11, 2017 19:59
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Well he just said "like the gas valve on your stove", not specifically that he was trying to control something flammable or pressurized. It could be, like, an air supply for an aquarium or something. But yeah don't mess with gas unless you're certified. In addition to being dangerous, it's usually illegal.
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Feb 11, 2017 20:20
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That's about how I felt when I saw an arduino compatible chlorine sensor. No one using an arduino has any business measuring chlorine gas.
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Feb 12, 2017 01:18
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Cumslut1895 posted:That's about how I felt when I saw an arduino compatible chlorine sensor. No one using an arduino has any business measuring chlorine gas. An arduino compatible chlorine sensor (assuming it's sensitive enough) strikes me as a great way to see if water you're holding has sufficiently off-gassed its chlorine to be added to a system with fish or other chlorine-sensitive critters.
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Feb 12, 2017 02:23
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Cumslut1895 posted:That's about how I felt when I saw an arduino compatible chlorine sensor. No one using an arduino has any business measuring chlorine gas. Maintaining a pool?
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Feb 12, 2017 03:35
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Sagebrush posted:Well he just said "like the gas valve on your stove", not specifically that he was trying to control something flammable or pressurized. It could be, like, an air supply for an aquarium or something. A use for such a thing that I've often contemplated building is an automated or semiautomated homebrew beer setup. Most of them are electric because obviously controlling a few relays with an whatever microcontroller or dev board you prefer is relatively easy. I have an all gas brewing setup as is though and I like brewing on gas. The last time I brewed on electric I literally ended up smoking my beer (candy sugar collected on the heating element). I'd really like to build a gas system but maintain the ability to have my DIY electronics actually operate the thing in the same way as the electric rigs. It wouldn't be connected permanently or semi-permanently to a home gas system, it would be running off standard grill cylinders while outdoors or at most in an open garage and then disconnected from the fuel source when not in use. Is that still not a thing someone should even think about DIYing?
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Feb 12, 2017 05:22
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It seems like the kind of thing you would want to get a purpose-made UL rated device to run the valve, and use a control signal to tell that what to do.
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Feb 12, 2017 05:48
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Go for it don't listen to these pussies.
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Feb 12, 2017 12:38
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wolrah posted:A use for such a thing that I've often contemplated building is an automated or semiautomated homebrew beer setup. Most of them are electric because obviously controlling a few relays with an whatever microcontroller or dev board you prefer is relatively easy. I have an all gas brewing setup as is though and I like brewing on gas. The last time I brewed on electric I literally ended up smoking my beer (candy sugar collected on the heating element). I'd really like to build a gas system but maintain the ability to have my DIY electronics actually operate the thing in the same way as the electric rigs. It's so popular there's a homebrew forum with several threads on it, which I ran into while googling around. Also, just to alleviate Coyo7e's petrified terror, I'm not hooking this up to the gas mains what is wrong with you, jesus. I used the stove gas valve example because I figured it was easiest to imagine and relate to. What I'm looking for is a general solution for a few different applications I'm thinking about working on as a hobby project. Mostly, it's precisely controlling air flow into things, like a squirt gun that doesn't need to be manually pumped to be pressurized. I was hoping to find an all-in-one solution to it so I'm not having to make specialty valve pairings every time I wanna make a new thing. However, yeah, googling around for proportional solenoid valve(thank you, rawrr) has them in the multi-hundred dollar range, so I guess I'll have to deal with it.
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Feb 12, 2017 14:18
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neogeo0823 posted:. However, yeah, googling around for proportional solenoid valve(thank you, rawrr) has them in the multi-hundred dollar range, so I guess I'll have to deal with it. You can also get valves that are conventional screw valves with a worm gear and motor to turn it, which are a bit cheaper (but slower of course). And for real precision, mass flow controllers (MFCs) which can be ridiculously expensive but you might be able to pick up a used/out of calibration unit for cheap on ebay or something. There are also specialised pneumatic valves used for doing pressure-based signaling through explosive or heavy EMI environments but they are hardly cheap either.
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Feb 12, 2017 16:51
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neogeo0823 posted:It's so popular there's a homebrew forum with several threads on it, which I ran into while googling around. When you started talking about stove valves instead of just being honest and saying you are brewing/distilling, I'm not going to bother with the benefit of the doubt that you're just throwing it out there as an example.. Whatever happened to that kid with the penchant for taking apart smoke alarms, the "Radioactive Boy Scout," they called him, iirc?  Also, distillation and brewing can be dangerous too. How many ACH do you have in your brewing area? 
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Feb 12, 2017 21:48
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coyo7e posted:Whatever happened to that kid with the penchant for taking apart smoke alarms, the "Radioactive Boy Scout," they called him, iirc? David Hahn. He died last year at the age of thirty‐nine.
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Feb 12, 2017 21:52
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neogeo0823 posted:Do any of you guys know of an electronically controlled, adjustable gas valve that can be hooked into an Arduino? Think like the gas valve on your stove, where you turn a dial to adjust the output to exactly what you want, but instead of a dial, it'd be connected directly to the controller. I'm googling around, but I'm having trouble finding anything that looks like it would work. Have you seen the movie "Fight Club" ? If not, watch the first half before proceeding with this project
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Feb 12, 2017 21:55
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Platystemon posted:David Hahn. He died last year at the age of thirty‐nine.  The wikipedia article states that when he was arrested again in 2007 his mug shot had obvious signs of radiation burns.
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Feb 13, 2017 10:51
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wolrah posted:A use for such a thing that I've often contemplated building is an automated or semiautomated homebrew beer setup. Most of them are electric because obviously controlling a few relays with an whatever microcontroller or dev board you prefer is relatively easy. I have an all gas brewing setup as is though and I like brewing on gas. The last time I brewed on electric I literally ended up smoking my beer (candy sugar collected on the heating element). I'd really like to build a gas system but maintain the ability to have my DIY electronics actually operate the thing in the same way as the electric rigs. .... Now then--you can get proportional electric-control gas flow valves but they tend to cost a lot of money, most are well over $100. This page talks about a guy finding a cheap one for only $70 - $100, where most of the more-accessible ones cost around $200: http://forum.homeroasters.org/forum/viewthread.php?thread_id=3506 But do you really need fully-proportional control? I bet that you don't...... You can buy lower-pressure 2-position solenoid valves around for only $10-$15 each. If you took your gas line, split it into 3 separate lines, and put one of these [on/off] solenoids on it and a different flow resrictor in each (such as, a manual valve adjusted only partly open) then you would have 7 different levels each. For a math example of how this is done: solenoid #1 is set to flow 1 cu foot per minute, solenoid #2 is set to flow 2 cu ft/min, solenoid 3 is set to flow 4 cu feet per minute. By turning on one, two or all three of these valves on, you can get 1,2,3,4,5,6 or 7 cubic feet of flow. Seven different flow rates, from only 3 separate on-off valves. Plus, since the control is automated, you can get more than 7 different rates. For example, if you used 3 valves to get 7 different constant flow rates, then you could have "half-step" rates where it would change back and forth between two rates every 30 seconds. So then that 7 levels becomes 7 direct levels + 6 "half-step" levels, for 13 total. And it's easy to control, because the solenoids just need a plain electronic solenoid to connect the power to them on or off. ,,,,, Secondly, you would probably have an easier time if you DON'T try to hook these valves straight to the propane tank. It would be a lot less stress on the solenoid valves if you used a regulator to drop down the tank pressure but still leave the flow rate as high as you need. ------- One thing I do know about fuel-handling pressure valves is that you should REALLY try to get ones that are made for the fuel you are using. A seal that can easily withstand 300 PSI of propane for years may fail in a matter of months if you subject it to gasoline or kerosene at 50 PSI. Metal seals will handle anything; for lower pressures you can usually use PTFE or flourinated PTFE for anything. I think......... ;>)
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Feb 13, 2017 16:23
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That's an interesting idea, basically the gas flow equivalent of one of those resistor-based ghetto DACs. That might be workable, but it seems like it'd be a lot more complicated than just connecting a servo and some limit switches to a manual valve. Definitely using an appropriate regulator and seals if I ever go down this rabbit hole, to me that was just implied but good call to mention it explicitly. wolrah fucked around with this message at 17:02 on Feb 13, 2017 |
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Feb 13, 2017 17:00
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I'm trying to connect a circuit on an ESP8266 to detect if an attached device is powered on. The attached device has a 5V signal that is always on when the device is on. I want to connect the attached device to the ESP8266 using a Sharp PC817 optoisolator, because that is what I have. The way I have it worked out in my head, the 5V signal will drive the LED side of the optocoupler, and the ESP will live on the transistor side. The typical current of the PC817 is 20mA and it wants 1.2V. I think this means I need to connect a 200ish Ohm resistor in series with pins 1 & 2 on the PC817 (5V---resistor---PC817---GND). Do I need to do anything fancy to connect the transistor side to the ESP8266, or can I just connect ground to one of the transistor side pins on the optocoupler, and one of the digital i/o pins on the ESP8266 to the other pin with no extra parts? Thanks for any help.
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Feb 13, 2017 19:32
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wolrah posted:That's an interesting idea, basically the gas flow equivalent of one of those resistor-based ghetto DACs. That might be workable, but it seems like it'd be a lot more complicated than just connecting a servo and some limit switches to a manual valve. When you think you've seen it all - you haven't even scratched the surface! 
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Feb 14, 2017 04:03
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Why does this have to be gas again and not a big electric heating element? You really want something that will fail safe no matter what. With your Arduino controlled gas setup what happens when a big gust of wind blows out the flame? Your temp sensor will see the brew start to drop in temperature and crank open the valve to maximum levels, at best venting the entire cylinder of propane and at worst... filling the area with propane and KABOOM when something ignites it. It's not worth the risk, and certainly not worth talking about on the internet where your home owners insurance might find out. Also if you don't see a lot of DIY automated gas brewing setups... that's a sign. The tech for it has been around and in hobbyist hands for 20+ years. Lack of documented projects should probably tell you something. mod sassinator fucked around with this message at 04:52 on Feb 14, 2017 |
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Feb 14, 2017 04:45
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IF you must make an Arduino‐controlled heater, start with an off‐the‐shelf model and connect the Arduino to the user‐accessible controls. Like, let the Arduino modify the temperature set point. Don’t have it control the valve directly.
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Feb 14, 2017 05:16
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mod sassinator posted:Why does this have to be gas again and not a big electric heating element? You really want something that will fail safe no matter what. With your Arduino controlled gas setup what happens when a big gust of wind blows out the flame? Your temp sensor will see the brew start to drop in temperature and crank open the valve to maximum levels, at best venting the entire cylinder of propane and at worst... filling the area with propane and KABOOM when something ignites it. It's not worth the risk, and certainly not worth talking about on the internet where your home owners insurance might find out. If you don't know how to do Air Change/Hour or cubic-feet/minute math for a structure and you do still intend to be using electronics and gases in an enclosed space - please speak up via PM - I would be very very happy to provide you with resources to make sure that you neither depressurize the structure, overpressurize it, or just shart gas all over and pray that a spark never ever ever happens.. Basically yeah, bad loving idea unless your whole setup is either sitting in open air outdoors - or you end up with a pro-grade HVAC solution to move/condition the air around your little hobby project. I mean all it takes is new windows and a cold snap to turn your whole home into a vacuum chamber and suck radon literally up out of the dirt in the crawlspace below your home - why not add an active CO2 project while you're trying to kill yourself and everyone else in the structure? I'm serious, gases are not something to play with lightly - even the ones that won't spontaneously combust.
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Feb 14, 2017 05:51
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Are there any good tutorials/ideas for projects that don't require a 3D printer but still looks good? I live in China and it's really easy to get components but I have no idea where to go about getting stuff 3D printed (I'm sure it's possible but I don't speak the language well enough). Also is there a good soldering guide? I'm buying a HAKKO FX-888D but I have very little experience soldering. a7m2 fucked around with this message at 16:19 on Feb 14, 2017 |
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Feb 14, 2017 15:49
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a7m2 posted:Are there any good tutorials/ideas for projects that don't require a 3D printer but still looks good? I live in China and it's really easy to get components but I have no idea where to go about getting stuff 3D printed (I'm sure it's possible but I don't speak the language well enough). As for soldering, you're starting out with a pretty high-end soldering tool, I think mine cost like 10-15 bucks. Be aware that tips need to be replaced, as they accrue grime and carbon and stuff. I'd recommend youtube videos for soldering demos and techniques, they help a lot. Also Practical Electronics: Components and Techniques has a lot of really useful info about different types of fasteners and glue, etc, which is very much important for when you step past the breadboard stage and begin to want to have things come together as a finished product. But whatever you do - make sure that you've got a nice strong fan and a duct leading outside, so you can push that poisonous lead-and-plastic-filled smoke away from your lungs while you are working.. An old vacuum or a large and burly case fan works really well. One of the biggest helpful tricks I learned when de-soldering stuff to scavenge parts,is to use a little bead of solder to "kickstart" melting the solder joints on whatever you're taking apart. Usually in manufactured stuff it seems like they use a higher-temp solder than you would use by hand, which makes it a PITA to remove caps and resistors and poo poo without damaging the PCB you're removing them from. Using a little drop of melted solder will allow you to melt the bead on the PCB faster, and remove stuff quicker, which means less chance of heat damage. But mostly it just takes a lot of practise, imho. coyo7e fucked around with this message at 20:38 on Feb 14, 2017 |
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Feb 14, 2017 20:35
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coyo7e posted:As for soldering, you're starting out with a pretty high-end soldering tool, I think mine cost like 10-15 bucks. Be aware that tips need to be replaced, as they accrue grime and carbon and stuff. If your soldering tips are getting all carbonized and wearing out, you're probably soldering at way too high a temperature or not cleaning/tinning the tips properly. Even the original tip I got with my Hakko 836 like ten years ago still works fine. The main failure method of a properly-treated tip is for the iron plating to wear off, and that takes a LOT of soldering. (Maybe you are just soldering all day every day). If you're saying that you've only ever used $10-15 Radio Shack style irons without a temperature control, that's probably why they seem to be disposable. A proper temperature-controlled iron will work much better. Also, you should always have a little bit of molten solder on the tip of the iron, just enough to spread across between the iron tip and the component and conduct the heat effectively. A dry, oxidized tip doesn't work well at all.
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Feb 14, 2017 22:20
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Start with building things in cardboard, foam board and heavy paper. It will help you learn about how to build things in an inexpensive way that requires minimal tools (just a sharp knife like an xacto blade and a good cutting surface). Learn things like how to join one flat piece to another, how to glue things, etc. It all seems like basic stuff but has a surprising amount of complexity. For soldering, get some cheap boards and just practice soldering things like headers on a lot. This guide has some good tips too: https://learn.adafruit.com/adafruit-guide-excellent-soldering/tools
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Feb 14, 2017 23:14
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Here's an old, but still fantastic, set of training videos. Some are kind of obsolete/uncommon (terminals) but are short and give good tips applicable to other things anyway. https://youtube.com/playlist?list=PL926EC0F1F93C1837
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Feb 14, 2017 23:42
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Sagebrush posted:Also, you should always have a little bit of molten solder on the tip of the iron, just enough to spread across between the iron tip and the component and conduct the heat effectively. A dry, oxidized tip doesn't work well at all. 
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Feb 15, 2017 07:42
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It's really difficult to get good at soldering without somebody standing over your shoulder going "No you idiot, you have to do THIS". It's really hard to learn and teach though, because it's just a thing you can suddenly do well, and it's really difficult to articulate what you're doing differently. It's a 'knack'.
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Feb 15, 2017 07:55
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Splode posted:It's really difficult to get good at soldering without somebody standing over your shoulder going "No you idiot, you have to do THIS". It's really hard to learn and teach though, because it's just a thing you can suddenly do well, and it's really difficult to articulate what you're doing differently. It's a 'knack'. seriously, at least borrow that book from the library and go over the sections on tools, and the chapter on joining methods and solutions - or you'll be a threat to everyone within 20 feet of your projects when they get big.
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Feb 15, 2017 08:04
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Splode posted:It's really difficult to get good at soldering without somebody standing over your shoulder going "No you idiot, you have to do THIS". It's really hard to learn and teach though, because it's just a thing you can suddenly do well, and it's really difficult to articulate what you're doing differently. It's a 'knack'. One‐on‐one, in‐person instruction can never be beat, but don’t be discouraged if you can’t get that. Soldering looks intimidating, but it’s actually easy. Solder wants to to go where it’s supposed to—you just have give it the right conditions. If you have a steady hand and can follow simple instructions, you can learn to solder in an afternoon. Here are some simple illustrated instructions (PDF). This video is kind of overly long, but Jones knows what he’s doing and has good close‐up shots. Platystemon fucked around with this message at 11:09 on Feb 15, 2017 |
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Feb 15, 2017 10:56
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The biggest tip I needed was "don't heat the solder, heat the part".
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Feb 15, 2017 12:59
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All great stuff, thanks guys. Turns out I found some small Chinese place that does prototyping for local factories and has a bunch of 3D printers. It's not cheap but it's not too expensive either. I also got a connect for people who will design 3D models for me for dead cheap if I really wanted that, but that's getting way ahead of myself. I'll just start with some small stuff with models found online. Maybe I'll even modify them a little myself. I'm really excited to get my soldering kit. The HAKKO FX-888D comes with a lot of high praise and is like half the price compared to what I'm seeing it sold for in the States. I'll try to find that book!
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Feb 15, 2017 16:21
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Anyone got tips on using solder braid more effectively? I seem to have a hard time heating through the braid and getting solder to flow. Sometimes I end up soldering the braid to the pins. This is with lead-free solder and some (I think/hope) quality techspray braid with fairly active flux.
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Feb 15, 2017 16:55
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Sagebrush posted:Also, you should always have a little bit of molten solder on the tip of the iron, just enough to spread across between the iron tip and the component and conduct the heat effectively. A dry, oxidized tip doesn't work well at all. I may have mentioned this before, but using this sagebrush advice as a jumping off point - you should also put a healthy blob of solder on the tip *after* you complete your joint, and *before* you put it back in the holder. This is called "idling" the tip, and will extend the useful life by...forever. The solder blob becomes a protective layer and will happily sit there and oxidize on the outside while the rich, creamy center stays nice and molten and shiny. When you're ready to solder again, dab the tip into your Hakko tip cleaner (if you don't have one of these, you're missing out on some goddamn magic) to clean the schmootz off, dab a little fresh stuff on there, and get to work. Repeat all steps as necessary. I have some tips easily approaching 15 years old that still work like new because of this One Little Secret Big Solder Doesn't Want You To Know. (it's not really a secret, it just isn't mentioned many places and doesn't get taught/learned much anymore.) Another fun fact: solder will flow towards the heat. Keep that in the back of your mind and watch how it behaves in your projects. Once you really see how it works, you can use it to your advantage and make some really pretty joints with less solder and contact time than you might be using now. Acid Reflux fucked around with this message at 19:00 on Feb 15, 2017 |
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Feb 15, 2017 17:05
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a7m2 posted:I'm really excited to get my soldering kit. The HAKKO FX-888D comes with a lot of high praise and is like half the price compared to what I'm seeing it sold for in the States. FYI, that means the hakko is probably counterfeit. Real 240v hakkos are typically 2x the price of 120v ones. Nobody really knows why, but you'll see plenty of complaining on hobby boards from Europeans and Australians about it. It'll probably work well regardless, the analog knockoffs do. (though it would be easier to do a poor job on a programmed controller of an otherwise we'll built iron.) Also, read the manual on how to set temp vs how to enter calibration mode. It's easy to accidentally enter calibration mode and screw it up.
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Feb 15, 2017 17:25
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Aurium posted:It's easy to accidentally enter calibration mode and screw it up. Yeah, this drives me nuts. The school's 888Ds are constantly getting their setpoints screwed up to the point where I just reset the iron any time I have to use one. They're great irons in every way, except that stupid interface decision. Entering calibration mode should be like a ten-second process or involve both the buttons or something, not "almost exactly the same thing you do to change the temperature"  I like my 836 for that reason. I don't solder anything where +/- 10 degrees is going to make a difference, and it's impossible to mis-set it otherwise because it's just a dial. Analog control all the way.
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Feb 16, 2017 02:35
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I think you hold the ENTER button for a second to start setting the temperature and that holding the other button fucks everything up, but I’m going by muscle memory here. I have a hard time remembering myself if I haven’t used that model in a while. Students don’t stand a chance.
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Feb 16, 2017 02:39
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Aurium posted:FYI, that means the hakko is probably counterfeit. Real 240v hakkos are typically 2x the price of 120v ones. Nobody really knows why, but you'll see plenty of complaining on hobby boards from Europeans and Australians about it. Hmm, thanks for this. The shop is legit and the price is similar everywhere I'm looking, but sadly you never know here. I'll see if I can't get a local expert opinion.
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Feb 16, 2017 05:26
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