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frarugi87

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  • frarugi87 made the instructable Acrylic Bending Tool
    Acrylic Bending Tool

    Just finished the core part. Still to be added: a fixed power supply, a regulator (I want a current controlled one rather than voltage) and a switch o automatically turn it off when I lift the moving part (so I do not have to move my hands from the piece to let it cool)

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  • frarugi87 commented on douwe1230's instructable UV Curing Station
    UV Curing Station

    Just a comment on the divider: your assumption is correct when there is nothing in parallel to the 10k resistor. But if the motor has an equivalent resistance of, for instance, 1.1k when rotating, then the total resistance will be 10k // 1.1k = 1k, which then translates to 6V on the motor. A very poor way to step down the voltage, of course, but still working

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  • Adjustable Wrench Super Mod

    Be honest, you got the idea from Lego, didn't you? ;)Great work :)

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  • The Ultimate Component Storage System

    Wow! Impressive :) This only lacks voice control :P(for instance see the Jasper project)

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  • Shelving With Concealed Toe-Kick Compartment

    Why don't you use a spring-based opener? Just like this: https://www.ikea.com/us/en/p/utrusta-push-opener-8...You give it a kick, and it opens. Without holes or keys...

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  • frarugi87 commented on JoeM114's instructable RFID Jukebox
    RFID Jukebox

    So you are using an arduino to read one byte from the serial line and put it back on the serial line? If all you wanted was a USB-UART converter.. Just buy it. No coding, no errors, no limitation on baud rate, and 1/10 of the cost.

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  • Another Brick on the Wall

    About the last step (you used exterior paint to change the space between the bricks), why didn't you paint it before the transformation? Was it to save color or it will limit the adhesion of the mortar?

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  • Solar Powered RGB LED Magic Pathway

    This is greatJust a question: is the light from 12 neopixels enough to light up the path (so you don't need further illumination) or it is more "decorative", and so the light produced is nice but not powerful?

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  • Bit Driver Ring (3D Printed, Wearable Hex Bit Driver)

    You made the design as a "hole"; isn't it a problem when you try to screw/unscrew and the bit just moves away from the screw instead of turning?

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  • frarugi87 commented on SparkyGiraffe's instructable One Pot Bolognese
    One Pot Bolognese

    This is the so-called "pasta risottata". I (well, my fiancée) made it a couple of times with cream and, ... well try it yourself ;)

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  • frarugi87 commented on Spartacus7's instructable Castle Coffee Table
    Castle Coffee Table

    How is the glass attached? Is it just leaned on top of the castle? If so, isn't it a bit unsecure?

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  • Erathostenes Apparatus

    It was not a single measure, and from what Wikipedia says the actual method got lost.In any case, since conditions are cyclic, you can just make a measurement today in one location and another in the other place next year...

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  • How to Make a Custom Garage Door Opener

    Did something like this on 2 cars, but I used a 12V remote instead of a 3V one, so I could connect the power to the car battery line (in one car to the radio, in another it was connected in the fuse box - of course after a fuse)

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  • frarugi87 commented on 8BitsAndAByte's instructable The Mesmerizer
    The Mesmerizer

    sorry, but.. Isn't the rPI a bit "too much" for this? Just for moving some motors I think that a simple microcontroller can do it...

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  • 2000 Watts Induction Heater

    There are some questions raising from the instructable:- You never mentioned the power supply; since you speak about 2kW I assume it is a 36V/55A- You wrote the code of the fuse holders, but never spoke about the fuse rating; given the input, I assume 2x 30A fuses are neededIf these are confirmed, then since the connector is rated 30A; it may melt under 55A current, or at least you are at 2x its current limitation

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  • Reuse Old Mobile Phone Batteries

    I suggest you to cover the wires going to the battery. Any metal object can make a short circuit and... well, I think you know what happens then...

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  • frarugi87 commented on MnMakerMan's instructable Solder Fume Extractor
    Solder Fume Extractor

    I think the schematic with the LM317 is wrong; the R2 resistor is hooked up to the wrong point (should be connected to ADJ)

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  • frarugi87 commented on deluges's instructable Table With Hidden Lamp
    Table With Hidden Lamp

    This reminds me of a picture i once saw.. A soldier instructor and a recruit:* Instr: "Private!"* Sold: "Yes Sir"* Instr: "I did not see you at the camouflage lesson"* Sold: "Thank you Sir"

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  • Smart World Map With Data Screens and DMX Programmable Lighting

    I think that the 3 PCs are overkill; just one PC and you are doneThen, if you strongly need 3 PCs, for synchronizing you can use a lot of cheaper approaches (e.g. use three USB->serial, then join the TX of the master and the RX fo the slave(s) and you have exactly what you have here, without the nanos). Ok, maybe 3x Arduino Nano is still nothing compared to 2 65" UHD TVs, but...

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  • How to Make a Softstarter

    From what I see, this circuit is used to limit the inrush current only.For instance, an inverter may have a very big input capacitor. When you connect the power, the current can be very high (even tens of amperes). When you put this circuit, the resistor is put in series with the load; at turn on the current is limited at 12V/3.3Ohm = roughly 4 A. This current slowly drops, due to the fact that the load's voltage slowly increases. After some time (selected by C1, R2, R3, and is around 0.5-1s for these values) Q1 starts conducing, and so the relay closes, bypassing the resistor (and so avoiding wasting power on it)

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  • DIY Risk-like Board Game (like a Pro)

    This is awesome.. Looks like a "professional" gameJust a question: did you use "normal" paper to print the map and cards? Or you used glossy paper or added a protection layer to make them more "time-proof"?

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  • frarugi87 commented on Crow Builds's instructable Neon Fallout Sign

    Can you confirm these are LED ropes? If so, where did you buy them? I never saw them..To me they look like EL wires (which are not LEDs, and work in a completely different way)

    Since you confirm these are EL wires, please fix the instructable... EL wire is not LEDRegarding the instructable, thank you. I have an EL wire string and now I know what I can do with it ;)

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  • frarugi87 commented on mblaz's instructable Reaction Training Dummy

    Why are you programming the AtMega off-PCB, and do not include an ICSP connector (like you did for the serial connection)?

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  • Last pictures seem like an X-Wing on the forest moon of Endor.. wonderful!

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  • Pretty impressive! It's a great work.anyway... "The ramen broth is made of two-part resin" I admit I did not know this... I thought it was water and meat :P

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  • Just a question: why did you limit the current changing the voltage and not the inverse? Isn't it easier to control the luminosity by changing the current?

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  • Great work... I like itJust a tip; the wheel seems made of plastic. This sometimes slip. You can use a small rubber band around it to increase the grip (if the case has enough clearance)

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  • Just my 2 cents.1) I think it is better to draw the schematic in a better way, so that it can be understood easily at a glance. This means, for instance, that the "logic" flow goes from left to right. I'm speaking specifically about the power supply circuit (T3, IC2, ...) which at first I thought was an output; it took me some time to analyse it and understand it was the power. If you put it on the left side of the uC then it is obvious. NOTE: I'm not one that follows this 100% of times, but anyway this is an advice I think is worth remembering when drawing2) I did not measure the clearances, but it seems to me that your high voltage traces are way too close one another. For 230V, the minimum distance two traces should have is in the range of several millimeters (3mm, if I'm not…

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    Just my 2 cents.1) I think it is better to draw the schematic in a better way, so that it can be understood easily at a glance. This means, for instance, that the "logic" flow goes from left to right. I'm speaking specifically about the power supply circuit (T3, IC2, ...) which at first I thought was an output; it took me some time to analyse it and understand it was the power. If you put it on the left side of the uC then it is obvious. NOTE: I'm not one that follows this 100% of times, but anyway this is an advice I think is worth remembering when drawing2) I did not measure the clearances, but it seems to me that your high voltage traces are way too close one another. For 230V, the minimum distance two traces should have is in the range of several millimeters (3mm, if I'm not wrong, and at least 6mm from the low voltage part). In your case some traces are way too close, which means it will fail sooner or later. And moreover the low voltage part is embedded into the high voltage one, so please consider it risky too. Luckily you will always use it when you are supervising it, so any flame can be detected instantly (you will, won't you?)As for the rest of the circuit, I was not sure about how you detect the current flowing in the saw. The only explanation I gave to it (but I cannot confirm, since no source code is provided) is that the atmel gives pulses and detect the current; when it senses current it increases the pulse duration. Does it work this way?Best regards

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  • I think you are out-of-spec for both a router battery and, definitely, for a UPS.The specification for your items are:- Battery: 3.7V, 4.8A current max- 12V step up: max 2A- Lithium battery charger: 1AIf you want to use the 12V output only, the router you have has a 12V 1A input. This means that the current required from the battery is 12V*1A/3.7V = 3.2A. The battery can sustain that, but I'm not sure about the boost (the maximum output current of 2A is probably at very low voltages, not at 3x the input voltage). Probably the 1A current for the router is the absolute maximum one, but some more calculations are needed. For sure you can't charge your mobile while the router is powered...Regarding the UPS usage, so using it while it is plugged in, the charger output of 1A will never be able …

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    I think you are out-of-spec for both a router battery and, definitely, for a UPS.The specification for your items are:- Battery: 3.7V, 4.8A current max- 12V step up: max 2A- Lithium battery charger: 1AIf you want to use the 12V output only, the router you have has a 12V 1A input. This means that the current required from the battery is 12V*1A/3.7V = 3.2A. The battery can sustain that, but I'm not sure about the boost (the maximum output current of 2A is probably at very low voltages, not at 3x the input voltage). Probably the 1A current for the router is the absolute maximum one, but some more calculations are needed. For sure you can't charge your mobile while the router is powered...Regarding the UPS usage, so using it while it is plugged in, the charger output of 1A will never be able to sustain the 3.2A current required. For this reason, you can't use it as a usual UPS.

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  • frarugi87 commented on TheTNR's instructable VORONOI HEART LAMP

    What is the purpose of step 8? Is it to have a clear finish without having to use finer and finer sandpaper?For clarity, moreover, I'd invert steps 4 (Making epoxy) and 5 (Assemble Voronoi Heart and Led), since you have a limited time to pour the epoxy (and so it is better to have the heart already assembled before mixing the epoxy)

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  • frarugi87 commented on DiggingFox's instructable Resistor Organizer

    I did something similar, but with 1.5ml test tubes (for SMD resistors).One thing I suggest you is to organise them in rows of 12 elements. Why? Because the resistors values are arranged in the E12 or E24 values range; the E12 is 12 values in a decade, so if you organise them in 12 elements rows you will have them sorted properly. If you have an E24 series you will have two rows occupied by one series, and then this will start again.In my setup I use some 72-holes containers (6 rows 12 columns), and I managed to store three decades of E24 resistors in a single box; consequently I have a 1-910 ohm box, a 1k-910k box and a >1M box (ok, this is not full, so I also have other values in this one).

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  • To reduce the complexity you could have wired only the D+, D-, GND and VCC wires. You would have lost the USB3 speed on the second drive, but... who needs it on a 32GB drive?Regarding the project, instead of a relay (which is large) you could have used just two MOSFETsFor the rest, good idea and good execution :)

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  • You can also make the drive inside the cable more secure through some SW like VeraCrypt. I never used it, but it was my top choice when I was researching ways to hide personal information on USB drives.

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  • Isn't it a bit risky to set the 5V DC-DC voltage AFTER mounting? this way if the screw is turned all the way to the 12V it will fry. It's better to set it before mounting, or at least turn the screw all the way to the 0V and then slowly increase while monitoring. Or the best solution IMHO: include a series element (a resettable fuse, a 0 ohm resistor, ...) that you do not mount at first, then set the voltage to 5V, then mount it as a last step to power the rest of the board

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  • Sometimes you just don't have any choice... Just like when me and my GF were searching for an apartment and the two-bowl sink was a must... FYI, one bowl for dirt dishes, one for soapy ones.

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  • Yeah, we'll try that as soon as we got some time to tinker with it. Thank you :)

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  • Yes, it works thanks :)Just a couple of things:1) there are some 10 ohm resistors; are they really 10 ohm or they are 10k?2) the images of the schematic are not very clear; maybe it is better to include the full resolution ones too as attachment (or, better, the schematic as a pdf)3) from the pictures it seems to me that the years print is 2019,2020,2021,2022,2021 (and not 2023). Is this a mistake?4) maybe it would have been easier to use the so-called charlieplexing technique rather than a full matrix, to save pins and componentsThank you for your project :)

    Thank you for your help ;)Just another question, since I'm not so much proficient with eagle: you can't modify the layout from the gerber only, can you? I wanted to learn something by slightly modifying your design (for instance switching PC4 and PC5 with PD0 and PD1 , so that I2C is accessible - for an RTC if needed) but without starting from scratch. Is it possible?

    The BOM file cannot be downloaded; is it just me or it happens to other too?

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  • If you flip the cards deck, thus leaving the bent card on the bottom (or better, glue the bottom card rather than the top one), you would have had a much nicer effect IMHO

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  • What about repeating the steps to apply a solder mask at the end?

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  • Another Cobblebot "proud" owner? :P

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  • Reading the datasheet, the sensitivity can be decreased bya) reduce the size of the sensor (which you cannot do)b) increase the distance (for instance put some plastic above the contact)c) add a capacitor between the sensor and ground.If you can't do solution b, then I suggest you to add a capacitor. I do not have these modules, but if I saw correctly the unpopulated pads in the top right corner of the board images are for this purpose. Just solder there a small SMD capacitor (10-50pF, in a 0603 or package I think, or a 0805) and the sensitivity should decrease. The larger the capacitor, the smaller the sensitivity (but do not go beyond 50pF)

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  • You will need a USB host controller, like for instance this:https://store.arduino.cc/arduino-usb-host-shield

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  • frarugi87 commented on Eric Brouwer's instructable LAN/Network Monitor

    I'm not sure whether the app you mentioned just scans once or continuously. In any case, I think this is designed to be on 24/7 and to consume very little power, while a Mac consumes, well, a bit more ;)

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  • Good project :)Just one note: usually you should put a small resistor (usually around 200 ohm) between the microcontroller pin and the gate of the MOSFET; this is used to limit the current at the very beginning of the turn on. This is especially true when using high power MOSFETs and PWM modulation, and you use both in your application. Moreover I prefer to also put a pull-up (pMOS) or pull-down (nMOS) resistor directly on the gate to ensure power down when the microcontroller is booting

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  • "I think I will have to wrap my husband the next time" This sounds scary... You are going to take him out of there, aren't you?

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  • Personally I think that 50W should be enough (I'll use a 50W myself). As for the dissipator, I think you are a bit confused. First of all the voltage is not 12V, but 34. Then this is a stroboscope, not a LED lamp. This means that it gets turned on for a very brief moment. Looking at the code, the LED gets turned on for 200us every cycle, and the cycle lasts from 2200us to I think 6624us. In the worst case, which is 2200, estimating a LED efficiency of 20% (which is very poor) the power dissipated by the LED is roughly 100W * 80% * 200/2200 = 7W. Will a copper heatsink be enough? I don't know, but I'm positive about this. And in any case if you feel it heating in your hand you can shut it down ;)

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  • I have a few comments/questions:- What is the point when measuring the voltage on the node between transistor and resistor? The Rds-on of the MOS is around 30mOhm, and with a current of roughly 0.5A this means a 15mV drop. Or a 0.3% of precision loss. Totally negligible- What is the purpose of the resistive dividers (R1-R3 and R2-R4) to measure the voltage? Your max voltage is 4.3V, and you are not usign the internal voltage reference, so the max voltage you can measure is 5V. Why are you dividing it in half?- Speaking of voltage references, are you sure that the 5V are stable? Even with the OLED? Personally I'd use the internal reference (and then you really need the R1-R3 voltage divider, but the resistors values should change) - You shouldn't drive a MOSFET that way; you should add a r…

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    I have a few comments/questions:- What is the point when measuring the voltage on the node between transistor and resistor? The Rds-on of the MOS is around 30mOhm, and with a current of roughly 0.5A this means a 15mV drop. Or a 0.3% of precision loss. Totally negligible- What is the purpose of the resistive dividers (R1-R3 and R2-R4) to measure the voltage? Your max voltage is 4.3V, and you are not usign the internal voltage reference, so the max voltage you can measure is 5V. Why are you dividing it in half?- Speaking of voltage references, are you sure that the 5V are stable? Even with the OLED? Personally I'd use the internal reference (and then you really need the R1-R3 voltage divider, but the resistors values should change) - You shouldn't drive a MOSFET that way; you should add a resistor in series (e.g. 220 Ohm) to limit the current peak at power on/off- Are you sure you can power the buzzer directly? (I couldn't find the data; what is the current it should get at 5V?)Thank you for sharing anyway :)

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  • I could not understand the power button circuit. How is it supposed to work? If the switch is not momentary, if I understood it correctly when it is open the PI is not powered, while when it is closed the PI power is removed. If this is the case, I would have wired it in the opposite way; in your way, when the board is turned off the 10k resistor generates a 500uA current, which is low but slowly drains the battery...

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  • In step 5's picture you are putting your fingers around the cables, since you have to rotate the encoder with your right hand and there are the cables in between. Maybe having them under the display (in the non-45-tilted area) would have been a better choice, wouldn't it?

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  • This is awesome! Good work!

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  • frarugi87 commented on mikeasaurus's instructable QR Coasters

    Maybe you can also pour some transparent resin on it, in order to have a flat surface and maybe a better look ;)

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  • Maybe you have already answered this, but.. Why did you put the buck converter before the bearings? I'd have put it after (i.e. on the moving part); this way the voltage on the bearings is not important, can be noisy, and moreover you regulate it after the bearings, so the current on the bearings is also lower

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  • This is a very cool project... or hot... ;)In any case, when you are done you simply turn on the tap to shut the forge off, don't you? XD

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  • How does the resin "blend" with other resin? I mean, if I apply another batch of resin, will I see the seam? Both when curing (i.e. in a few minutes/hours from first application of resin) or after some time (e.g. one year after, to cure scratches for instance)

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  • I would have appreciated more the photos of the steps, rather than the photos of the "ingredients" and then a single step telling "mix everything and you are done"

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  • Just came here today and... This is horrible............ Really horrible :P

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  • If it becomes "too hot to hold", doesn't it soften also the PLA?

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  • frarugi87 commented on khinds10's instructable Magic Mirror

    What do you use on the tablets? I mean, do you manually open the browser? or you have some automated script or app that opens and browses to the correct website?

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  • Can you further explain it? Cause I opened the code and inside there is actually a neural network, a classical MLP implementation which tries to avoid the light...

    If you look at the code you'll find two basic functions, one for training a neural network and the other to execute the calculated values. Personally I've always preferred to train the NN on a PC and to just execute it on the embedded micro, but I think the author wants this to be an educational project.BTW the neural network he is using is called Multi-layer perceptron (MLP), and is one of the "historical" neural networks

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  • HelloI see that there are a few things missing from the code, so I'm asking them here. Basically the control of the system is1) if the temperature is less than 45°C, turn on the heater and circulate the air with the fan2) if the humidity is greater than 30%, circulate the air with the fan (and the silica dessicant will de-humidify it)Is this correct?

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  • Maybe I did not explain myself enough for q1 ;) I read that the Vih was too high, so at least one stage was required. That's why I suggested you to invert the rPI output (and keep the transistor); the nMOS turns on with the 3.3V pulse from the rPI, and so you get a 5V output on the other side.Note, however, that if you want to power the inverters at 5V you'll need the LS family, not the HCT.As for the dual power supply, I think that if you want to properly isolate everything you'd better keep separate grounds too (and use opto-isolators on the data lines). This will also solve your level-adapting issue ;)

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  • There are some inefficiencies:1) why did you put the inverters too? You just need to invert the signal outputted by the rPI. Or, if you prefer not to invert it, use a 74LS04 hex inverter (TTL levels) and use two inverters in series (you have 6, so you can convert all the 3 channels). A 5V powered TTL port accepts voltages as low as 2V for the high value, so even 3.3V logic is ok for them.2) why didn't you use the 5V from the HDD cable to power the rPI? you can easily avoid another cable coming out of the box....

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  • First of all, this is impressive... O_OI just have a couple of questions, because here you showed a list of steps to assemble it, but there are a lot of unanswered mechanical, electrical, electronical and informatics questions (of course you could not write here a massive amount of steps, this instructable is already long on its own) ;)Mechanics: what are those springs under the shoulder? Why are they needed?Electric: this robot is a wired one, right? I mean, the power supply comes from the mains. Why did you use two power supplies?Electronic/informatic: so on the robot you have one arduino and one mobile phone. Are they linked (I mean, the mobile is used for "high level" control and the arduino for the "low level", i.e. the direct control of the servos) or the mobile …

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    First of all, this is impressive... O_OI just have a couple of questions, because here you showed a list of steps to assemble it, but there are a lot of unanswered mechanical, electrical, electronical and informatics questions (of course you could not write here a massive amount of steps, this instructable is already long on its own) ;)Mechanics: what are those springs under the shoulder? Why are they needed?Electric: this robot is a wired one, right? I mean, the power supply comes from the mains. Why did you use two power supplies?Electronic/informatic: so on the robot you have one arduino and one mobile phone. Are they linked (I mean, the mobile is used for "high level" control and the arduino for the "low level", i.e. the direct control of the servos) or the mobile is only used for displaying the face and the high level control is done through an external PC or something else?Mechatronic: what are its (or his/her, I don't want to offend if he/she is already sentient) capabilities? Optical recognition through the webcam, interaction, grabbing objects, walking, ...? Did you already program he/she/it or this is "just" the mechanical part (note the "just".. I feel a bit silly by referring to this work with a "just").And... Thank you for sharing. You really made this look very simple :)

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  • Is this just an advertisement of your service or an instructable? If it is an instructable, can you explain how it works?

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  • You are totally mad... This is impressive!Just one note: what if someone who can't swim follows the whole instructable and then at the end reads the last step? XD

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  • I'd point out that teh capacitors are "bulky", which means they are gone (the top side must be flat for the capacitor to be ok).Moreover when dealing with this kind of equipment I have the habit to pass a screwdriver on the contacts (particularly the ones of the input capacitors) before approaching with my hand, in order to completely discharge them. And a lot of times you can see sparks....

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  • In my opinion, that UNO is totally useless. You can save the money by just integrating the code inside the rPI.Also the two batteries are useless. Just use one (either the power bank or the lipo one) and use a proper circuit to power the other part (a buck converter if you keep the lipo, a boost - if needed - if you just keep the power bank)

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  • Sorry for the pretty noobish question but... How did you make the cuts for the saw blade? I see one is at 90° and the other at 45°, but how did physically make them? Maybe the 90° is easy, since you just have to try and follow the screws, but the 45° is a bit trickier for me

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  • Cool for demostration purposes, but with a relay rated even for 100k operations using it continuously for 140 operations per second will make it last for about 12 minutes...

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  • Maybe it'd be better to put some "delay" between the displays, in order to compensate for the doors, so that the text will appear to "flow" under the doors instead of appearing directly on the other display instantaneously

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  • Sorry, but... Why don't you use a 3D scanner instead of the MRI? You only need to remove the brain from the cranium, but just remember to put it back like it was before and you should be ok...

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  • frarugi87 commented on LarsWH's instructable Smart Rack for Headphone

    I like this, but there are a couple remarks I have to make:- First of all the Arduino here is overkill here. A simple op-amp or comparator would have been pretty enough.- If you want to use the Arduino, add some functionalities: make it less sensitive to ambient light by modulating the light output, for instance (you can sample the output of the sensor with and without light to see if there is change); or you can make it controllable by the PC, or... well, it has a lot of possibilities- From the HW point of view, not much to say except THE FLYBACK DIODE! Whenever you use an inductive load (motor, relay, ...) you have to put a diode to let the coil discharge at shutdown. The most classical way is to put a diode (best if it is a Schottky one, but for low power even a 1N400x is better than n…

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    I like this, but there are a couple remarks I have to make:- First of all the Arduino here is overkill here. A simple op-amp or comparator would have been pretty enough.- If you want to use the Arduino, add some functionalities: make it less sensitive to ambient light by modulating the light output, for instance (you can sample the output of the sensor with and without light to see if there is change); or you can make it controllable by the PC, or... well, it has a lot of possibilities- From the HW point of view, not much to say except THE FLYBACK DIODE! Whenever you use an inductive load (motor, relay, ...) you have to put a diode to let the coil discharge at shutdown. The most classical way is to put a diode (best if it is a Schottky one, but for low power even a 1N400x is better than nothing, even if it is usually slow - note: x is a number from 1 to 7; I usually use the 1N4007, since I don't find 1N4001 around and it cost almost the same) . So the diode goes in parallel with the load, in such a way tha in normal operations it does not conduct (so, in your case, the anode is connected to ground and the cathode to the collector of the transistor)

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  • Maybe it is a stupid question (I'm not much into wood-working) but... Why did you do the big holes first and then the small ones? Wasn't it easier to first drill the center holes and then use them to center the big ones? Or the big bit you used already left a center starting hole?

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  • frarugi87 commented on TheCircuit's instructable USB Mini PCB Drill

    Isn't the drill bit a bit (sorry) off-center with this kind of linking?

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  • For item 2 I think you are right.. My badAs for the led voltage, yes. As a rule of thumb usually red non-high-brightness leds (those with a red transparent cover) are rated at 1.5V, green non-HB at 1.8V, blue, white and high brightness ones (those with a clear cover) around 3V. But they vary a lot with the manufacturing and conditions (current, temperature, ...) even among the same lot. Usually I find cheap chinese torchlights with some (even 8 or 9) white leds in parallel and powered directly by 2 AA. They work, of course, but the LEDs last much shorter than they would if powered properly...

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  • This is just a start, but... I think your program can be much better.IMHO there are two major flaws with your program.1) you will need to keep the button pressed for on average 500ms (at most 1s) to have it opened, since the control is performed every second2) I think that the servo moves very quickly (usually servos move in a very short time)To solve point 1, you can simply reduce the "delay(1000)" line to, for instance, "delay(50)". After all, when it is closed you do not have to wait.To solve point 2, I'd suggest a complete rewriting of the program. My personal ideal implementation is the one of a finite state machine with 4 states:- CLOSED: when entering, print "Pay toll". Exit conditions: when button is pressed go to opening- OPENING: slowly open the gat…

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    This is just a start, but... I think your program can be much better.IMHO there are two major flaws with your program.1) you will need to keep the button pressed for on average 500ms (at most 1s) to have it opened, since the control is performed every second2) I think that the servo moves very quickly (usually servos move in a very short time)To solve point 1, you can simply reduce the "delay(1000)" line to, for instance, "delay(50)". After all, when it is closed you do not have to wait.To solve point 2, I'd suggest a complete rewriting of the program. My personal ideal implementation is the one of a finite state machine with 4 states:- CLOSED: when entering, print "Pay toll". Exit conditions: when button is pressed go to opening- OPENING: slowly open the gate (see details below). Exit conditions: when finished, go to open- OPEN: wait 2 seconds. Exit conditions: when finished waiting, go to closing- CLOSING: slowly close the gate (see details below). Exit conditions: when finished, go to closedTo slowly open/close the gate, you will have to have a part of code executed every X milliseconds that increments or decrements the current position towards the target position. Something likeif ((millis() - prevUpdate) >= 100) { prevUpdate += 100; if (currentPos > targetPos) { if (currentPos - targetPos > 5) currentPos -= 5; else currentPos = targetPos; } if (currentPos < targetPos) { if (targetPos - currentPos > 5) currentPos += 5; else currentPos = targetPos; } servo.write(currentPos);}You set the target position to what you want, then this code automatically moves the servo for you in the desired position.With these values, it will move the servo by 5 every 100ms (this means that the transition 0->90 will take 1.8s).As for rewriting it as a state machine, I implement it with a standard structure (this is pseudo-code). WARNING: very long code, which is a bit generic to show you MY best way to handle this kind of problemsFirst define the states and declare the variable to hold the current state of the state machine:enum SM_states { closed, opening, ... };SM_states current_state;then, in the loop, you have to1) evaluate if there is the need for a state change:SM_states next_state = current_state;switch (current_state) {case closed: if (button_was_pressed) next_state = opening; break;...}2) check if there is a variation in the state, and if so perform any exiting or entering condition:if (next_state != current_state) { switch(current_state) { // Exiting conditions; in this program there is none } // Actually change state current_state = next_state; switch(current_state) { // Entering conditions; for instance in closed you will print "Pay toll" }}3) perform the actions to be performed during the state:switch(current_state) {// In this case you can either put here the servo advancement or do nothing, and advance the servos all the time}With this structure, the program will be much more powerful (changing the program will be very easy, and it is very predictible). This structure can look very complicated, but it isn't and it is easily scalable

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  • Please beware that1) that one is NOT an USB-cable. Applying 5V directly to a LiPo battery will, if you are lucky, only produce the "Smoke-effect"(TM). If you aren't, well, check what an exploding LiPo battery does. If you want to charge it in a better way, embed a LiPo charging circuit in your application2) LiPo batteries should never be overcharged or be used for too long; if their voltage drops below a certain point you will make them unusable (that's what battery monitors are for). Your battey will not last too long without one (unless you constantly keep it well charged)3) Not putting a resistor in series is a really bad habit. This is the first image I found, and as you can see different LEDs behave differently. And can you see how steep is the curve above 3.4V? Very bad ha…

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    Please beware that1) that one is NOT an USB-cable. Applying 5V directly to a LiPo battery will, if you are lucky, only produce the "Smoke-effect"(TM). If you aren't, well, check what an exploding LiPo battery does. If you want to charge it in a better way, embed a LiPo charging circuit in your application2) LiPo batteries should never be overcharged or be used for too long; if their voltage drops below a certain point you will make them unusable (that's what battery monitors are for). Your battey will not last too long without one (unless you constantly keep it well charged)3) Not putting a resistor in series is a really bad habit. This is the first image I found, and as you can see different LEDs behave differently. And can you see how steep is the curve above 3.4V? Very bad habit...For the rest.. Well, I particularly like the effect of the silica balls. I will keep it in mind for the future ;) thanks

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  • Sorry but... Why are you posting the same article with different premises?https://www.instructables.com/id/PRINCIPLE-OF-MAGL...https://www.instructables.com/id/Generate-Electric...

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  • Sorry but... Why are you posting the same article with different premises?https://www.instructables.com/id/INFINITE-TIME-SPI...https://www.instructables.com/id/PRINCIPLE-OF-MAGL...

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  • Sorry but... Why are you posting the same article with different premises?https://www.instructables.com/id/INFINITE-TIME-SPI...https://www.instructables.com/id/Generate-Electric...

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  • Thank you for your reply..Just to point out, my "risky" was not about breaking the MOS (the Vgs max is 20V, so no risk on this side), but on the fact that you may not be able to fully turn it on. Ok, now you have only 2.5m of leds, and I think this equates to roughly 0.5A of current, but then why choose a 75A MOS? Moreover look at figure 1 on the datasheet: look at the differences between 5V and 4.5V to understand how features degrade quickly when near the Vgsth value; then consider these are the typical values (what is typical between 2 and 4V of Vgsth?). Personally, I'd think of using even a smaller MOS (with Id-max between 2 and 20A) but with a lower Vgs-th, to be sure to fully turn it on with 5V or 3.3V.On the other side, ok for the RSSI; but then I think the arduino is supe…

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    Thank you for your reply..Just to point out, my "risky" was not about breaking the MOS (the Vgs max is 20V, so no risk on this side), but on the fact that you may not be able to fully turn it on. Ok, now you have only 2.5m of leds, and I think this equates to roughly 0.5A of current, but then why choose a 75A MOS? Moreover look at figure 1 on the datasheet: look at the differences between 5V and 4.5V to understand how features degrade quickly when near the Vgsth value; then consider these are the typical values (what is typical between 2 and 4V of Vgsth?). Personally, I'd think of using even a smaller MOS (with Id-max between 2 and 20A) but with a lower Vgs-th, to be sure to fully turn it on with 5V or 3.3V.On the other side, ok for the RSSI; but then I think the arduino is superfluous. You are NOT using a DAC peripheral on the arduino, simply because there are no DACs on arduino. And moreover a DAC will not work correctly with your setup. What you are using is creating three PWM waves (you can see this with an oscilloscope on the arduino outputs: a DAC creates a steady DC voltage, while a PWM is a square wave and the ducy cycle is adjusted so that the average value is equal to the steady voltage); the rPI is capable of generating this voltage on his own.My personal suggestions are- if you want to change the MOS, choose one with a Vgs-th max of about 1V; this will enable you to use it directly with the rPI- if you don't want to change the MOS, put another stage in between, to power it with the 12V. For instance, put an NPN (or a small nMOS with Vgs-th low) with base towards the rPI, emitter to gound, emitter connected to +12 through a pull-up transistor and the gate of the MOS. This way you will be able to fully turn the IRF on and make performances better.Just a quick search on RS showed that the IRF1404 costs about 2.4€ each; if you change it with a SOT-23 packaged MOS (SMD mount, so smaller circuit - but they are easy to solder also on a perfboard) I found the FDN337N (2.2A of max Id, 30V Vds max, 1V Vgs-th max, 0.24€ each). If you want to stich with through-hole devices, the IRL2703 is in TO-220 case (24A Id max, 30V Vds max, 1V Vgs-th max, 0.98€ each). Again, this is a very quick search on RS; other suppliers will have lots of other devices, with different prices and characteristics. Just pick your favourite ;)

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  • I see three major flaws in your electronic design (I assume you are using IRF1404, since I could not find any IRF1504)* The MOS is not a logic level one; with a Vth of at most 4V it is risky to use 5V to power it...* Usually it is much better to put a resistor (about 200 Ohm) between any logic pin and the gate of the MOS, because at turn on a high current can flow* Using a rPI and an Arduino is totally overkill. I did not dig into the "machine learning" part, but if it is simple enough to be implemented on a microcontroller (e.g. by tracking the time when the user puts the phone nearby) then you can move it to an arduino (maybe with an HC-05 for the bluetooth). If it isn't, you can directly power the MOS from the rPI (of course, you need a logic level MOS - with a Vgs-th much lo…

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    I see three major flaws in your electronic design (I assume you are using IRF1404, since I could not find any IRF1504)* The MOS is not a logic level one; with a Vth of at most 4V it is risky to use 5V to power it...* Usually it is much better to put a resistor (about 200 Ohm) between any logic pin and the gate of the MOS, because at turn on a high current can flow* Using a rPI and an Arduino is totally overkill. I did not dig into the "machine learning" part, but if it is simple enough to be implemented on a microcontroller (e.g. by tracking the time when the user puts the phone nearby) then you can move it to an arduino (maybe with an HC-05 for the bluetooth). If it isn't, you can directly power the MOS from the rPI (of course, you need a logic level MOS - with a Vgs-th much lower). But.. Don't use another complete board just to avoid using a board properlyBest regards ;)

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  • A few comments.1) using 6 dip switches here can be, IMHO, a problem. You can leave two of them on (then what is the voltage you will have?), or you can open the connected one, maybe to switch the voltage, thus putting the output to 10+ volts, which may fry the board. Maybe it was better to put a switch also on the output..2) you made a board that could arrive to two lanes. Why didn't you make this dual channel? It is much better to have two power supplies...

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