I’d suggest peeling off just one strand of the wire and use that. You will need to insulate the wire from the nail - Wrapping paper around the nail will do. You will need to insulate the wire from itself, so that adjacent turns don’t touch. You can just space the turns out along the paper sleeve. That should do the trick. If you have twine, you can wind that on with the copper wire and use the twine to keep the turns from touching each other.
Oh to straighten copper wire, if you don’t know this trick - hold your nail in a vice and wrap a single turn of copper wire around it. If you then pull on one end of the wire, keeping a little tension on the other - with a bit of practice it will give you a very straight end result, as the wire pulls away from the nail.
As other have mentioned, what you got is fine for most basic applications. If you use a polygon pour you can decrease the resistance of the trace and consolidate it all into one large trace. I also see you using traces for ground, the general rule is if you have the room, make all the unused space on at least one of your layers ground with a polygon pour. This makes connecting ground easier, makes your ground more reliable (decreased resistance) and makes your board less susceptible to external noise
That’s interesting, so you can flip the relays all you like without trouble as long as the 24DC supply isn’t connected? If that’s true then your problem presumably isn’t the typical inductive kick from the relay coil. It looks like your relay board has stuff on it which is presumably drivers and snubbers so let’s assume all of that is adequate to the job.
So, if it’s inductive kick from the valve solenoid it’s being coupled all the way from there, back through the 24DC supply to the outlet, then forward through the USB supply to your shift register, which is impressive! But not implausible.
Anyway, three places I’d add some stuff:
The main thing you need is a snubber network across the valve solenoid coil itself, ideally physically close to the valve (you want to minimize the area of the loop formed by the valve coil - wiring - snubber). Something as simple as a freewheel/clamping diode would probably help a lot. This will also improve the lifespan of your relay contacts which are probably arcing a little.
Small decoupling cap on your breadboard, say 0.1µF on the power supply rails, to keep your logic happy.
Larger decoupling cap on your 24VDC rails (the bus on the left), just to eat any transients the snubber doesn’t deal with. Maybe 1-10µF or so?
Thanks for your thoughtful response… and sorry it took so long to get back to you. I tried different combinations of capacitors, a diode on the load lines, etc… nothing worked. And then I put a 0.1uF capacitor directly between the power leads on the valve itself… and everything started working fine. Admittedly, I’m not 100% sure why… but I won’t complain :)
That makes sense, it forms a simple snubber network. A capacitor in series with a low-value resistor might work even better. Did you try a freewheeling diode directly across the valve leads?
Not entirely sure, but maybe these help you somehow:
The relay has a coil which requires 0.35W. The chip seems to have a maximum output current of 35mA.
The ‚switch on current‘ of an inductive load is usually 3 to 5 times higher than the ‚hold‘ current.
The valve may not have a free-wheeling-diode. This could create an issue by creating strange voltage spikes on all your supply voltages (connected by GND).
Yeah, decoupling cap here might as well just help OP fry the chip more effectively by ensuring it can sink all that current.
Solution here is probably a transistor/MOSFET that the chip turns on, which in turn turns on the relay. Relay coils are inductors, so that probably also needs a diode to protect the transistor from inrush current and also the kickback when it turns off: inductors resist changes, so it’ll try to keep sinking the current and result in temporary spike of very high voltage: spinningnumbers.org/a/inductor-kickback.html
Usual situation - if I needed to interface to 5 cameras I wouldn’t start with ones that needed: “The DVP physical interface consists of a single, 100-conductor, 110-ohm cable organized. as 45 differential signal pairs. These signal pairs consist of the following: • 36 RGB data pairs. • 2 clock pairs.” So, you would be interfacing to 5 x 45 differential pairs. I’d be looking for camera modules with serial output…
Or, as you suggest, give each camera something that can convert that lot into a single serial data stream. Or even process it down to a QR code and just send that. Or even do what-ever it is that you want to do with that code, once received.
Connecting each camera to its own ESP32, which process the data and sends only necessary information to the main ESP32, I think is a cool idea.
I plan to use this Schamatic as a guide for building the ESP32 cam parts on my pcb, although I’m sure I’ll be using a slightly newer ESP32: github.com/SeeedDocument/…/ESP32_CAM_V1.6.pdf
It seems that the PINS U0TXD and U0RXD are free. Can I use these to connect them to the main ESP32 via UART or is there a better way to connect all ESP32 cams to the main ESP32?
And there is one more question. How can I program the ESP32 of the cams? The main ESP32 will be connected to a Micro-B SMD USB connector. Do I need another one for each ESP32 (for the cams) or is it possible to program all ESP32 via the same USB connector?
Depends on your programming abilities. You can set up a “1-Wire” bus and put the lot on that. You could have one microcontroller as master and the rest as slaves - your external USB connection would go to the master and it could, in theory at least, then pass on program upgrades to the others. Clearly they would all have to be programmed individually, originally. But, quite frankly, the investment in time and effort on setting all that up? If you had dozens, hundreds - then yes. But you only have a small hand full. I’d just bring out their USB connections and program them individually, via those. I think each one has a unique identifier, stored in ROM - so they could all run the same software and include that identifier in messages on the bus.
Is the ground for the voltage rail and input signal the same?
Yep.
What exactly is wrong with the circuit I built? I want the LED to only turn on when 5V is supplied at the input, right now the LED can turn on if I connect the ground to the voltage rail supply even without an input voltage.
Schematic of exactly what you did… not what was on paper, how it is on the breadboard.
I’ve seen the post on Adafruit with the feedback resistors connected to the same ground as the rail supply, but the circuit diagram does not show where the input voltage ground is? Link: blog.adafruit.com/…/ask-an-educator-making-a-non-…
Use a single power suppy (GND and +12V) and tie the Arduino’s GND with that GND.
Your circuit fails because the Arduino’s GND is tied to the -12V from the dual power supply, so the +5V that the Arduino outputs equal to -7V on the non-inverting input. Since this is a non-invering schematic, the opamp doesn’t invert the signal. Instead, it tries to double the -7V to get -14 on the Out, but since you’re powering the opamp with -12V, it can’t achieve a voltage that low, so it outputs the maximum it can give: -12V.
The LED turning on even when there’s no signal on the non-inverting input is probably a floating input problem. It picks up EMI so it just amplifies that. Try connecting the non-inverting input to GND, the LED should turn off… that or you burnt one of the opamps, lol, try the other one in the package.
I tied the Arduino’s GND to the power supply GND, the output is still 10V, tried different ICs as well, not really sure what the issue is at this point. Tying the non inverting input pin to ground does turn OFF the LED, but the led stays on regardless if the 5V is coming from the arduino or not, it seems that the op amp outputs 10V regardless of the non-inverting pin, however if I use different resistors to lower the gain or change the input voltage to 3.3V instead of 5V, I do get the output voltage. I just don’t understand how there can be 10V at the output with no voltage from the inverting or non-inverting pin.
Well, you should get 10V. You input 5V, the voltage gain is 2, so the output should be 10V. I don’t see a problem here, the circuit is working as expected.
Thanks for your help! Looks almost identical, but not exactly! The little plastic tabs on the edge are a bit further apart on the connector you send me. Or at least that's what it looks like on pictures I find:
Here the little plastic tabs are roughly above pin 1 and 5, on my connector it's more above pin 2 and 4... Hope you can understand what I mean. Any idea?
That seems to be it! Or "JST-PH"? Not sure what the difference is between PH and PHR-5. 2mm pitch seems to be it at least, and plastic tabs seem to be at the right place:
As far as I know are the “PHR” series connectors a variant of the “PH” connectors. They also have a 2.0 mm pitch, but they differ slightly in their housing design. The primary difference in the “PHR” connectors is the presence of a latching feature on the housing. This latch helps to secure the connector halves together, providing additional stability and preventing accidental disconnections.
In general, what I remember from step up converters, is that they work more efficient the less they have to step-up. So a conversion from 4 to 12V is less efficient than a conversion from 8 to 12V.
But I also remember that after a certain input voltage the change in efficiency is only minimal. According to the datasheet of the MT3608 this seems to be around 4V.
Therefore I’d connect them in series, but I’m looking forward to other peoples input on this.
Grind it into dust, add sand, pour molten non-recyclable plastic into it (e.g. recyclable plastic with too many impurities). Market it as a weighted ballast material e.g. for the base of IKEA lamps.
output impedance of the signal generator you use to generate the square wave. When you set it to low, output impedance of the signal generator builds a voltage divider together with the internal pull up, and the device ends up sensing a higher voltage than "low". This is something you can see if you have an oscilloscope, try to hook up a probe to the input and ensure whether you get what you set in the signal generator.
some signal sources have no or limited capacity to drain current. And when you set it to low, this is exactly what it us supposed to do, drain current from the internal pullup.
As you mentioned in another comment, solution is a simple buffer. This could be an opamp, but even a simple nmos transistor should suffice (open drain as you said). But you need yo be careful with current ratings of the transistor, which you can easily calculate by dividing 5V by the pull up resistor. Send a message if you need help.
Before these, I suggest you yo use an oscilloscope or multimeter to measure the voltage when it is supposed to be low, and see that in fact the problem is that voltage at the input doesn't go "low".
I measured the signal generator alone, not connected to the input. It goes to 4.5V high and 0.001V low. Then I connected it to the input and measured at the input. I got 4.5V high and 1.1V low.
Also I ordered the 74LVC1G07 buffer along with a breakout board which should allow me to hook it up inline and test. I'll report back when I do.
It should do the trick I think. If you are working on electronics a lot, you may consider buying a breadboard and variety of resistors, capacitors and nmos, pros, bjt transistors in bulk for quick fixes instead of waiting for orders to proceed. Have fun
I own an iPhone since it fits my use case with a retail presence, (more) available repair, longer (if murkier how much exactly) software support, customer support and local backup option. (iTunes)
Out of the box it’s a superior privacy experience to a Pixel but if you’re someone who wants to tinker, there’s less potential. Personally, I don’t want to have to “work” on my phone these days and Google’s engineering snafus haven’t been reassuring. (Google Drive “fix” then sticking head in sand when problems persist, Android 14 bricking…)
and my most personal reason is that they made my Moto Z Play materially worse by removing the OK Google with screen off feature to push the then-new Pixel and pretended it never was supported.
Edit: Yes, obviously an unpopular opinion but really think about what you want. Buy used to be more environmentally minded, do you want to tinker with your phone? Fairphone is neat, but tradeoffs are all over the place.
I got you, the caveat is that a DIY battery replacement is going to be easier than say a Pixel 6 (no main board removal necessary.) and will still work.
Yes, their software locking of features (like TrueTone) and less availability of original parts is reprehensible, (luckily those are less critical functions for now but they wont stop there.) I won’t get battery health metrics but it’s about the tradeoffs you want. (See: Pixel Watches outright being considered unrepairable by Google. I’m not sure how easy it would to secure nearby battery service on a Pixel - but at least it’s available on iFixit for DIY…)
Yep, I’ve done plenty of custom ROMs, used most mobile OSes out there, etc. but I’m not joking when I say I don’t want to deal with SafetyNet, figuring out what works with/without Play Services and generally getting in bed with Google hardware (but that last bit isn’t privacy oriented.) And no way do I have the time to tell mom how to install Graphene and support it.
Apple’s on-hardware processing for some things is a plus as well. Yes I know it’s their current business plan and can change but they make money on hardware and services, not knowing things.
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