glass and electronic - Page 1
Forum section: electronics / projects

author: Hannah
author_rank: Newbie
timestamp: November 05, 2024, 05:31:08 pm
content: Hi evryone, I am a student glassblower and am looking for some advice about a project I am on. My plan is to create a vessel that has rings around the outside that when I place a test tube into the ring it sets off a trigger and a water pump goes off on a timer. I am a beginner at the whole electrical side and although this may be complex i am looking forwards to learning and getting this to work. So far i have an arduino, a solenoid valve(NC), a peristltic pump and a very basic understanding of what to do. any advice, no matter how complex will be greatly appreciated. thank you!!

author: Andy Chee
author_rank: Super Contributor
timestamp: November 05, 2024, 05:45:25 pm
content: Is there anything unusual about this proposed vessel with rings?For example, will this vessel be heated? chilled? contain corrosive liquids? or does the vessel have an unusual shape? what material is the vessel made from?Your trigger could be anything from a microswitch, magnetic reed switch, ultrasonic range detector, to video camera.The more details about your proposed setup, the better and more specific advice we can give.The Arduino timer is by far the simplest and most obvious part of this project. A timer program is trivial to implement on an Arduino. The wiring to the pump should also be relatively simple, but will need details on the pump specifications.

author: Hannah
author_rank: Newbie
timestamp: November 06, 2024, 05:51:32 pm
content: Hi Andy, thanks for your reply. to answer your questions, theres not much unusual about the vessel and rings. nothing will be getting heated up or chilled or and corrosive liquids just water. every thing is made form clear furnace glass. i have put up a sketch of what i am hoping it will look like.the pump is a peristaltic pump that takes 12 V and 5w. hope this helps, any more questions i will answer to the best of my knowledge.Thanks

author: inse
author_rank: Super Contributor
timestamp: November 06, 2024, 06:27:17 pm
content: I cannot imagine any other solution than to mount microswitches to sense the presence of the test tubes.But there are two problems: you will have to route wires along the vessel and the only way to mount anything to the glass is glueing and that may be neither reliable nor aesthetical.I don’t have experience with image recognition, but that’s probably beyond arduino capability

author: I wanted a rude username
author_rank: Frequent Contributor
timestamp: November 06, 2024, 06:32:54 pm
content: Adding to Andy's excellent overview, you might want to step back and consider whether this could be anXY problem. That is, we can help you with the electronic side of such a device, but is the overall idea for the device itself the best solution to your project? Some related questions:Do lab technicians actually like rings for retaining test tubes?What do test tube holders normally look like, and why do they look like that?How would the rings or other holders be attached to the vessel?Glass vessels normally don't have steel set into them, why is that?What are the ergonomic implications of having test tubes distributed around the vessel instead of in a rack?How will the vessel be held: by clamps, a stand?Of course, none of this is to suggest you shouldn't do it the way you've envisioned it. Your drawing has a lovely aesthetic to it, which laboratory glassware often lacks. This is more of an engineer's perspective ... asking the question, is the device something that the end users would actually enjoy?

author: inse
author_rank: Super Contributor
timestamp: November 06, 2024, 06:48:10 pm
content: Latest after the drawing it was clear to me that this was more like an artistic installation than laboratory equipment - no?

author: Analog Kid
author_rank: Super Contributor
timestamp: November 06, 2024, 06:54:00 pm
content: I think it's safe to say that this is an art project, certainly not any kind of lab equipment. (Unless the OP tells us otherwise.)Since the test tubes will be held by rings, which I assume are metal (and therefore must be glued to the vessel somehow), how about some kind of proximity detector, like elevator buttons? Thin wires could be attached to the rings and glued to the glass in a somewhat unobtrusive way, and a circuit could detect the test tube being placed by capacitance or some other method, yes?Sounds do-able to me. Dunno exactly how, though.

author: Gregg
author_rank: Super Contributor
timestamp: November 06, 2024, 07:12:06 pm
content: I would first try the reed switch and magnet approach as previously suggested by Andy. For a prototype, the reed switch glass tube could be glued (hot glue to test the concept) to the vessel and a small magnet glued to the bottom of the test tube. The magnetic flux pattern and its relation to the reed switch is important.There are lots of small relay modules available from the usual suppliers of Arduino components with opto isolation to isolate the pump power from the delicate reed switches.

author: Hannah
author_rank: Newbie
timestamp: November 06, 2024, 07:52:04 pm
content: so first of all yes this is more of an art project rather than actual lab equipment. the rings are too going to be made from glass which are hot attatched through the making process. this is just one piece in this project with a whole backstory but saves me explaining it all. the vessel is held by a clamp stand around the neck. the device doesn't have a user/operating goal but its about the filling up of the vessel by having a response to external stimuli, in this case represented by the test tubes. im not bothered about seeing wires and the operational componants either. I have also been given a sort of basic starter kit for this including a breadboard, a mosfet, 5v regulator, 555 timer, and a load of resistors. forgive me for the lack of understanding but i have given it a go with trying to create some sort of functioning circuit out of these all but i am getting very confused with it all. like i said i am before even beginner level at this all and have some very dumb questions to start with which watching video of how to set this up arent answering so any sort of advice would go a long way. i know its not great but at the minute soldering isnt an option so how do i connect the mosfet to the arduino and so forth? thanks for the brilliant replies so far, i appreciate the help)

author: Andy Chee
author_rank: Super Contributor
timestamp: November 06, 2024, 08:20:39 pm
content: Let's experiment with the 555 timer first, and put aside the Arduino for now.Try building this project, which may be along the lines of what you want to achieve:http://www.learningaboutelectronics.com/Articles/555-timer-monostable-circuit.phpThe circuit can later be refined to accommodate appropriate triggers and your water pump, but experiment with the 555 monostable as it is presented.The circuit can also be implemented in an Arduino program sketch which potentially offers more flexibility (or complexity!), but as I said, let's just play with the 555 for now.

author: inse
author_rank: Super Contributor
timestamp: November 06, 2024, 09:11:47 pm
content: I would suggest to start with the most challenging part: sensing the tube insertion.Do research on micro switches and think about how to attach and wire them.Reed contacts may be too fragile and also require correct orientation of the magnet, which is undefined at round objects like test tubes.And if this is solved, go on with the electronics

author: Manul
author_rank: Super Contributor
timestamp: November 06, 2024, 09:31:43 pm
content: Given the level of experience, I don't think it's time to play with the 555. You need to start with sensing. The most simple way would be a microswitch. You may be able to find smaller ones. Or maybe a force sensor mounted between a vessel and a ring, so you can detect weight of a tube (more advanced).

author: inse
author_rank: Super Contributor
timestamp: November 06, 2024, 09:53:15 pm
content: All the artistic aura gone 🥲

author: Manul
author_rank: Super Contributor
timestamp: November 06, 2024, 10:00:14 pm
content: Quote from: inse on November 06, 2024, 09:53:15 pmAnother idea would be to mount a microswitch together with a ring, so the thickness of a tube sliding in activates it. Might be more aesthetic, not sure.

author: inse
author_rank: Super Contributor
timestamp: November 06, 2024, 10:06:00 pm
content: All glass, hand crafted <headscratch>

author: jpanhalt
author_rank: Super Contributor
timestamp: November 06, 2024, 10:20:38 pm
content: I enjoy glassblowing, and while not a professional, while in grad school, I stood in for the temperamental departmental glassblower who resigned. I read your posts and still have no idea of what you are trying to make. Can you try explaining? Attaching test tubes to the outside of a large round flask, if done in that order, might be a lot more difficult than it seems.

author: Manul
author_rank: Super Contributor
timestamp: November 06, 2024, 10:33:07 pm
content: I wonder, how good it would work if small force sensing resistor would be glued to the wall and then the ring would be glued on top... Probably doable, but could be finicky.

author: antenna
author_rank: Frequent Contributor
timestamp: November 07, 2024, 12:34:42 am
content: You might be able to disguise the wires as some decorative copper pattern made of foil tape on the glass. Perhaps on those tape foil traces could be some kind of IR proximity sensor. I wonder if there exists some sort of IR led/detector in a small SMD package.

author: Analog Kid
author_rank: Super Contributor
timestamp: November 07, 2024, 12:39:36 am
content: I'm not sure why nobody else here seems to like my capacitive-sensing idea: I can't say for sure it would work, but it seems to me that if it did work it'd be a hell of a lot simpler than any kind of switch (mechanical like a microswitch or a reed switch).Could it work? I'm thinking of the big illuminated elevator buttons that you don't have to push in order to operate them. Don't those work by using a small RF field and measuring the disturbance when someone's finger gets close to it?And would that be within the capability of a DIY n00b here (no disrespect intended to the OP)?

author: antenna
author_rank: Frequent Contributor
timestamp: November 07, 2024, 12:47:34 am
content: Quote from: Analog Kid on November 07, 2024, 12:39:36 amSeems bulky and complicated. Maybe it wouldn't be, but it seems like a lot of hardware for a simple job that a contact switch can do.It wouldn't have to be a premade switch either. A strip of foil tape around the neck of the test tube would do it..

author: antenna
author_rank: Frequent Contributor
timestamp: November 07, 2024, 01:06:32 am
content: If it were a simple contact via foil tape, it could be AC coupled so it don't hold the trigger on the 555. The trigger cannot be held low or the timer output cannot change. Since the trigger pin needs to be pulled down, but only momentarily, run the trigger line to one of the contact points on the ring and the other side of the contact points goes to ground via a capacitor. Since the cap starts off discharged, setting the tube in the ring will close the contact, and since the capacitor takes time to charge to the trigger voltage, it will pulse low instead of being held low.One foil strip around the test tube neck, one broken foil strip on the ring from the 555 to ground with a cap on the ground side. Simple.

author: inse
author_rank: Super Contributor
timestamp: November 07, 2024, 01:39:29 am
content: The rings are formed from glass, so each one will be individual - no chance that it will make a reliable (if any) electrical contact.Don’t propose complicated electronic solutions like capacitive sensing to a novice.

author: Analog Kid
author_rank: Super Contributor
timestamp: November 07, 2024, 01:41:21 am
content: Quote from: antenna on November 07, 2024, 12:47:34 amBulky and complicated? Far less than any kind of switch: the only "hardware" needed would be a wire or two.But what I'm not sure of at all is the electronics required. Anyone care to sketch out for us the circuitry required?Hey, if this idea isn't feasible, then so be it.

author: inse
author_rank: Super Contributor
timestamp: November 07, 2024, 01:52:11 am
content: Here‘s the theory behind it:https://ww1.microchip.com/downloads/en/Appnotes/Capacitive-Touch-Sensor-Design-Guide-DS00002934-B.pdfHere’s some product:https://www.ebay.de/itm/226362062944?mkcid=16&mkevt=1&mkrid=707-127634-2357-0&ssspo=si_rstkxq22&sssrc=4429486&ssuid=UJEfguXdQ76&var=&widget_ver=artemis&media=COPYMaybe it works, needs to be tried out…

author: Analog Kid
author_rank: Super Contributor
timestamp: November 07, 2024, 02:17:07 am
content: OK, thanks for that.They show using a microcontroller (of course, Microchip). Any chance this could be done with a simpler circuit, say something based on a 555?

author: inse
author_rank: Super Contributor
timestamp: November 07, 2024, 02:27:22 am
content: Don’t overcharge an electronics novice, it should be a readily available solution, I would suggest.The electronics needs to be close to the sensor array, so it probably wouldn’t get smaller than something like in the eBay link.

author: Analog Kid
author_rank: Super Contributor
timestamp: November 07, 2024, 02:30:02 am
content: Good advice. Let's wait for the most easily implemented solution to appear here.

author: inse
author_rank: Super Contributor
timestamp: November 07, 2024, 02:32:06 am
content: Quote from: Analog Kid on November 07, 2024, 02:30:02 amSwitch

author: Andy Chee
author_rank: Super Contributor
timestamp: November 07, 2024, 02:42:48 am
content: Let's not forget the second major design requirement by the OP, a timer of some sort.Quote from: Hannah on November 05, 2024, 05:31:08 pmNormally a 555 would be able to do this job. But if the OP's requirement demands for a particular combination timing sequence of test tubes, then an Arduino may be better suited.

author: Analog Kid
author_rank: Super Contributor
timestamp: November 07, 2024, 03:30:54 am
content: Since the OP wroteQuoteI think that means just one test tube triggering the event, and a timer that (I'm assuming here) turns the water pump off after a certain interval. So no need for a microcontroller, I don't think.

author: Andy Chee
author_rank: Super Contributor
timestamp: November 07, 2024, 04:03:31 am
content: Quote from: Analog Kid on November 07, 2024, 03:30:54 amSo what happens when a second (or third) test tube is inserted before the timer runs down? What happens to the timer when a test tube is removed?It is this timing behaviour which the OP needs to describe.

author: Analog Kid
author_rank: Super Contributor
timestamp: November 07, 2024, 04:37:49 am
content: Well, sure, that's their job.In the meantime, our job is to come up with a workable scheme for triggering a circuit by placing a test tube in a ring.Seems like the foil-conductors-as-switch might be the easiest way to go here.

author: inse
author_rank: Super Contributor
timestamp: November 07, 2024, 04:43:33 am
content: Hannah, without basic electronic equipment like soldering iron, wires, side cutter, a multimeter and basic understanding of electronic components it will be hard to finish this project.Are you familiar with Arduino programming already?No one there to support you locally?I mean if it’s part of your education, how could they throw all stuff at you which is far from your discipline and expect a result?

author: Andy Chee
author_rank: Super Contributor
timestamp: November 07, 2024, 08:21:27 am
content: Quote from: Analog Kid on November 07, 2024, 04:37:49 amAnd until the OP describes their proposed trigger-timer relationship, we cannot know whether a 555 or an Arduino is the simpler solution.

author: nali
author_rank: Frequent Contributor
timestamp: November 07, 2024, 11:07:30 am
content: I think a better approach woild be just to put a load cell in a base, and use the Arduino to continually check for the added weight of test tube(s). Google "Arduino weight sensor" for some ideas.

author: Analog Kid
author_rank: Super Contributor
timestamp: November 07, 2024, 07:28:37 pm
content: So OP,@Hannah: Could you tell us how you intend this thing to work? Meaning what happens when, in what sequence, when test tubes are placed or removed. You don't need to use any technical terms, just explain the sequence of operation of the installation. That way we can figure out what's needed electronically to make it go.Be as complete in your description as you can.

author: Hannah
author_rank: Newbie
timestamp: November 08, 2024, 03:34:34 pm
content: hi, hope these pictures help to understand. the rings are hot attached and would like it to function by a snesor picking up on the test tube being put into the rings which then sets off the pump to let water through into the large vessel. hope this helps

author: CatalinaWOW
author_rank: Super Contributor
timestamp: November 08, 2024, 06:09:44 pm
content: Even small microswitches are relatively large. Opto-interrupters tend to be smaller and could be made to work in a variety of ways include having hinged flag that is pushed into the path by the test tube or using a transmitter-receiver pair and having a patch of paint on the test tube.Hall devices can be tiny indeed, and adding a magnet to the test tube (or having the magnet on the ring with a ferrous pole piece on the test tube) would be very compact and reliable.Ultrasound is another option which could be discrete. The approach would be to sense the change in damping that occurs when the test tube is inserted.Other questions come to mind. Do you want any single test tube to start the action, or must all the rings be filled? Do they have to be filled in a particular order, or does the order of filling change the rate or other character of the filling. Does which ring is filled control how much fluid goes into the vessel?Some of those operations would lend them selves to having an optical fiber between rings with the coupling path going through the test tubes (and thus changing the coupling).Other possibilities would include the use of polarized light in the sensor and quarter wave plates in the test tubes so that coupling was poor until the tubes are inserted.A lot of this will depend on your artistic vision. Maybe those on this forum can help once you have picked an approach that is consistent with your vision.

author: Analog Kid
author_rank: Super Contributor
timestamp: November 08, 2024, 06:40:14 pm
content: Quote from: Hannah on November 08, 2024, 03:34:34 pmThanks. Don't want to bug you, but you didn't really answer the question. Since we can't read your mind, whatexactlyis the sequence of events you want to happen? Is it just the one test tube being picked up that you want to start the pump? And does the pump then go off after a certain interval?If you could give us a complete description of the action, including everything that can happen to the device (like what if the test tube gets replaced before the pump goes off? things like that), it would really help people here to figure out how to implement this electronically. If the sequence is really simple, then the electronics should also be simple.

author: Hannah
author_rank: Newbie
timestamp: November 11, 2024, 02:15:16 pm
content: sorry my bad. so i would like every test tube to be able to trigger of the water pump by putting it into the ring. yes so the pump will have to be coded through the arduino to only go off for a maybe 3 to 5 second interval then back off. ill just reexplain the whole thing i guess. what i want to happen is that any test tube being put in a ring will set off the water pump to let water out for a few seconds. i would like it to work that if there is no test tube in the ring the circuit will not be complete therfore the pump and valve are not activated so if the test tube gets taken out like you sugest to get replaced it willl just stop and start. so sequence should be test tube into ring pushes switch which completes circuit and sets the pump off and opens the valve for a few seconds then back off. hope this helps

author: inse
author_rank: Super Contributor
timestamp: November 11, 2024, 03:03:41 pm
content: No need for Arduino, then - a simple timer circuit can do that.If you don’t want to get into electronics, time relays are readily available as well.

author: Hannah
author_rank: Newbie
timestamp: November 14, 2024, 08:42:02 pm
content: Hi everyone, Thank you so much for all of your help, I have got very far in this project and have learnt so much. I have gone with the reed switch option, thank you for the suggestion! so the left side of my breadboard is the 12V and the right is 5V, the arduino is coded so that when it recives input pin 11 on high (5v) which will be from the reed switch making contact to give the output on pin 8 for a few seconds. (i have got them in the wrong way in the picture i forgot to check the code properly). My question is with the reed switches, after soldering them to the wires, where do i put them in the breadboard to make it into a parallel circuit, i will have 4 to 5 reed swiches. thanks in advance

author: Andy Chee
author_rank: Super Contributor
timestamp: November 14, 2024, 08:56:20 pm
content: The way I understand your test tube behaviour, is that you want each individual tube to independently trigger the pump?If that's the case, connecting the reed switches in parallel will not give the desired effect. What would happen is that after one tube is inserted, subsequent tubes will have no effect.Given that you've decided to go with an Arduino, I would give every reed switch its own separate input pin on the Arduino. This also has the advantage of flexible timing changes by simply rewriting some code.

author: Hannah
author_rank: Newbie
timestamp: November 15, 2024, 11:16:29 am
content: that is a very good point, i hadn't thought of that. thank you!!

author: daqq
author_rank: Super Contributor
timestamp: November 15, 2024, 09:07:15 pm
content: The simplest solution is indeed a microswitch of some sort - this is electrically trivial. They come in small forms and it might be possible to hide them in a way that does not distract from the art too much.If you can use custom test tubes, it might be possible to embed a single loop of wire and sense that with a single turn inductor? That could be discrete enough.There's probably a bunch of more exotic techniques that do not require visible wiring on the sculpture itself, like tuned mechanical glass resonators that get de-tuned when a tube is inserted, visual inspection (a camera and image processing), possibly some fiber optics with invisible light doing the actual detection, or even these fellows:https://www.rvmagnetics.com/, but these would require a lot of skill to implement. Like 95% of the time of the whole projectGood luck with your project!

author: Kasper
author_rank: Frequent Contributor
timestamp: November 16, 2024, 05:39:46 am
content: Congratulations, I think you have made it through the hardest steps.Here are some limit switches you could use:https://www.digikey.ca/en/products/filter/limit-switches/198I would mount to the underside of the ring so it presses against the side of the test tube.If you want to reduce the number of wires, there are other options but that will likely complicate it.

author: Hannah
author_rank: Newbie
timestamp: November 26, 2024, 06:26:26 pm
content: Hi, me again!i have sorted all the electronics out and there seems to be a problem somewhere, starting off with the code i am just checjing through everything. is there anyone on here that could check this code for me. thank you. i want the script to do the following : switch pin 8 high for 5 seconds when any of the pins 9, 10, 11 and 12 are high. (high being 5 volts from the reed switch). thank you// Define the pinsconst int pin9 = 9;const int pin10 = 10;const int pin11 = 11;const int pin12 = 12;const int outputPin = 8;// State variablesbool isOutputHigh = false;unsigned long outputStartTime = 0; // To track how long pin 8 is HIGHvoid setup() {// Set input pinspinMode(pin9, INPUT);pinMode(pin10, INPUT);pinMode(pin11, INPUT);pinMode(pin12, INPUT);// Set output pinpinMode(outputPin, OUTPUT);// Ensure the output starts LOWdigitalWrite(outputPin, LOW);}void loop() {// Check if any of the input pins is HIGHif (digitalRead(pin9) == HIGH || digitalRead(pin10) == HIGH ||digitalRead(pin11) == HIGH || digitalRead(pin12) == HIGH) {// If pin 8 is not already HIGH, activate it and record the timeif (!isOutputHigh) {digitalWrite(outputPin, HIGH);isOutputHigh = true;outputStartTime = millis(); // Record the time pin 8 was set HIGH}}// Check if pin 8 has been HIGH for 5 secondsif (isOutputHigh && millis() - outputStartTime >= 5000) {digitalWrite(outputPin, LOW); // Turn off pin 8 after 5 secondsisOutputHigh = false; // Reset the state}}

author: inse
author_rank: Super Contributor
timestamp: January 14, 2025, 05:51:53 am
content: What happened to your project, Hannah?