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1 vote

How can I control a 5HP single phase motor with an Arduino UNO?

The required electrical parts and their ratings are as follows: F1 - Single-pole Miniature Circuit Breaker - 63 A. K1 - Motor Contactor - AC3, 32 A. F2 - Bimetal Overload Relay with manual reset - ...
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Failing diodes and shorting NMOS and PMOS in H-bridge at 19A

You can modify your existing circuit by adding large value gate resistors to reduce turn-on time along with Schottky diodes for fast turn-off time. Properly chosen for your particular MOSFETs, you ...
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4 votes
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Failing diodes and shorting NMOS and PMOS in H-bridge at 19A

Three problems: 1N4004 is rated to 1A, not 20A. And it is too slow. You can use the FET body diodes instead. They should not conduct often if the FETs are driven synchronously, so there should be no ...
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0 votes

Failing diodes and shorting NMOS and PMOS in H-bridge at 19A

To "limit" shoot-through, add an inductor series with your power supply (100 nH->1 uH). This should limit your di/dt to 120A/us - 12A/us. Simulated with 0.5 ohm load. Made with microcap ...
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3 votes
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Do you understand this circuit?

Those two buttons on the left are intended to be read using an analog to digital converter. They don't provide a simple digital signal. There's probably a pull up resistor on another circuit board. ...
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0 votes

Do you understand this circuit?

Left buttons are different. Press one button and current starts to flow via 39 ohms only. Press another button and current starts to flow via 39 ohms and 242 ohms. The right buttons are the same.
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How to make my sound reactive LEDs with Tip31C work?

The outputs of the PAM8403 are at half the DC supply voltage which will keep the transistors and LEDs turned on most of the time. You need series input capacitors feeding the 100 ohm resistors to ...
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0 votes

Interfacing OV7670 camera with STM32F4 (no FIFO)

So this is probably too late to be helpful but I would like to answer this for others who google this. There are a lot of missing details so I will try to answer it very generally: Firstly, It IS ...
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0 votes

ESP32 S2 hanging but only when not connected to serial

you're going to have to figure this our by trying different things, eg: disconnect the USB data lines and leave only the USB power lines, see what happens. try same with only the USB ground line ...
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2 votes
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Suitable sensor for very faint vibrations in metal

Piezoelectric wafer sensors work well for this, but using them effectively requires more knowledge than a hobbyist typically has, in terms of the circuit design needed. You can't simply connect them ...
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0 votes

Some Information Needed About Resistors

A few situations (by no means an exhaustive list): when you need to limit current, such as driving an LED, when you have a semiconductor driving in one direction and need a passive device to pull the ...
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0 votes

Some Information Needed About Resistors

The main applications are: voltage dividers conversion between current and voltage signals and vice versa in frequency filters in conjunction with e.g. capacitors coarse current limiting for safety/...
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0 votes
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Using Arduino LED instead of LiPo charger (TP4056) CHRG + STDBY LEDs

As @Lundin pointed out, just make the connection directly to the Arduino board. My suggestion is to replace the LEDs with 10k resistors, as in the modification shown below. The voltage to the Arduino ...
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1 vote

MOSFET being driven by an Arduino won't turn on without a 1M pulldown resistor

Your gate threshold voltage Vgs for that FET is 2..4 V. Your Uno processor may run from a 5 V supply, but is probably outputting a bit less. You don't want to be too close to the threshold, or you may ...
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0 votes
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Are these MOSFETs wired correctly?

One problem is the supply switch of the water-level sensor. You can turn off the sensor by disconnecting GND of the sensor as your circuit shows. But if you do so, the positive supply is still present ...
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1 vote

Making a simple (but useful) oscilloscope using an Arduino Uno

First: method n°1, namely a "non inverting amplifier" is only capable of amplifying a signal, not attenuating it. Method n°2 draws current from whatever you're measuring, so depending on how ...
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0 votes

Making a simple (but useful) oscilloscope using an Arduino Uno

You've got more problems than you realize. You've named two, and I'll add another two that you'll have to address. Voltage limits. You will have to scale large voltages down to fit the full scale ...
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0 votes

Making a simple (but useful) oscilloscope using an Arduino Uno

First: you need some time a divider (voltage too high) or an amplifier (voltage too low). A mix of the two is thus interesting. Second: don't forget that it takes some time for the Arduino to convert ...
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5 votes
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Arduino Uno prescaler, not measuring what I expected

Since you set TCCR1A = 0 and TCCR1B = 0000 1011 you are using clear-timer-on-compare mode (...
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3 votes
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2-stroke engine interferes with Arduino project

Are you sure it is the microcontroller that is crashing and not just the I2C comms to the LCD getting corrupted with noise? I can't see any pull-up resistors on your I2C bus in your schematic, so this ...
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  • 3,687
5 votes

Arduino Uno prescaler, not measuring what I expected

It looks to me like your code is dividing again by 2, by inverting PORTD_2 at each interrupt. That would explain why the frequency is half what you expected. If instead you set and reset PORTD_2 at ...
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1 vote

How to make water flow sensor work to measure flowed water and not flow rate

Looks like if you keep the flow rate between 600l/hr and 120l/hr you can use 2.05ml/pulse and get a fill within -1.8%/+0.9%. You can graph the flow rate during the fill and get an idea of how ...
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0 votes

Arduino Uno prescaler, not measuring what I expected

You are counting two counts with the timer so it does not generate overflows every prescaled tick but every two prescaled ticks.
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1 vote

How to make water flow sensor work to measure flowed water and not flow rate

Take the flow rate to frequency table and convert it into to fluid per pulse table, then every time a pulse comes count that as a bit more fluid delivered. look at the time ellaspsed since the last ...
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2 votes

How to make water flow sensor work to measure flowed water and not flow rate

You can expand the conversion table into lookup memory for more accuracy on interpolation as it has some nonlinearity. LPH / 3600 x 1000 = mL/s (milli-Litres per sec. Vs pulse per second) to get ...
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5 votes
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How to make water flow sensor work to measure flowed water and not flow rate

If you look at the flow rate vs output frequency, it's fairly linear. If you don't mind a few % error and just assume that it is linear that makes this very easy. Simply count the pulses coming out of ...
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0 votes

Power supply switching off and on again after load drop

OFTEN issues like this are caused by inductive spikes which occur when coils are powered off. These produce spikes on the power wiring and cause processor maloperation. If not already installed, add a ...
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4 votes

Why does a Pt100 RTD fail after immersion in thermally conductive and electrically isolating paste?

Seems pretty benign. Zinc oxide (the usual component in thermal paste) in a silicone grease carrier. The element itself in those bare sensors is passivated except where the connections are, and ...
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0 votes

Why does a Pt100 RTD fail after immersion in thermally conductive and electrically isolating paste?

It sounds like maybe the paste hardens near 10°C and places mechanical stresses on the Pt100
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16 votes
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Why does a Pt100 RTD fail after immersion in thermally conductive and electrically isolating paste?

These are "naked" RTD and are exceptionally fragile. Look at them in the wrong way and they break. Essentially, there's the platinum coated chip and the wires are simply bonded to it. No ...
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2 votes
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Capacitor keeps exploding on nixie HV power supply

From MC34063 datasheet the 680pF cap on pin CT sets the frequency to something like 45kHz. It's not very accurate but let's go with that. A 45kHz period lasts ~22µs. With 12V input and 160V output, ...
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0 votes

74HC595 8x16led matrix arduino

Separate from other aspects mentioned before, there is one simple fault: Writing decimal 250 to the shift register will only turn on 6 of the 8 bits because 250d = 0xFA = 1111 1010 binary. 255 is the ...
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0 votes
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Arduino USB Protection

Should I wire the power supply to the LED strip directly or should I use the power jack on the Arduino UNO directly? You should wire it directly to the LED strip. The LED strip and the power supply ...
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0 votes

Relays or MOSFETs

A normal bipolar transistor let the current flow, maybe you let 1mA flow into the base and 100 times of this current can flow through the collector. But the current must be delivered by the power ...
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2 votes

Suitable sensor for very faint vibrations in metal

Another suggestion - assuming this is a steel rail then glue a magnet to it and place a free standing coil over the magnet. Any vibrations will induce a current in the coil. Amplify/filter and ...
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2 votes

Relays or MOSFETs

(I´ve been told that MOSFETs amplify current signal) Not true. MOSFETs do not amplify current. However, a buck DC converter, often implemented with MOSFETs, can output more current than is input. As ...
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1 vote

Relays or MOSFETs

Should I connect more batteries in parallel or should I switch to a MOSFET H-bridge motor driver instead of the relays? (I´ve been told that MOSFETs amplify current signal) and if so, which driver do ...
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1 vote

Suitable sensor for very faint vibrations in metal

Gramaphone cartridge with the stylus resting on the rail and a suitable preamp? Capacitive displacement sensor? Laser interfeometer? Plenty of ways to measure small vibrations.
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1 vote

How can I change the output pin9 and pin10 into pin5 and pin6?

The program uses high frequency hardware PWM capabilities of TIMER1. The outputs are fix assigned in hardware to pin 9 (OC1A) and 10 (OC1B). There is no option to reassign them to other outputs. Pin 5 ...
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0 votes

Powering a 12V horn from an Arduino and generate siren wailing

The circuit is with one exception rather safe for the Arduino and the Transistor as well. The Arduino is protected by the collector-base diode of the transistor. If you want to increase safety margins ...
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1 vote
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Can a K-type thermocouple measure both air and surface temperatures?

There is no reason a thermocouple can't be used to measure surface temperature. This is done all the time. However, note that the air and the thermocouple wires will be conducting some heat to the ...
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1 vote

Can a K-type thermocouple measure both air and surface temperatures?

There are many different constructions of thermocouples. A thermocouple is simply two dissimilar metals joined at one point. Anything beyond that is optional. If you want to measure temperature up to ...
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1 vote

Controlling a 12V solenoid lock with 3.3V - IRLZ44N

Although it is stated that it is a "logic-level gate drive" where "Gate Threshold Voltage: 1<VGS<2" in the mosfet datasheet, mosfet is acting weirdly with a gate voltage of 3....
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1 vote
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Controlling a 12V solenoid lock with 3.3V - IRLZ44N

The Rds(on) is only guaranteed with a minimum drive voltage of 4.0V. 3.3V is less than 4.0V. Possibly the MOSFET is heating up which typically decreases the Vgs for a given current. If you got the ...
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1 vote

Is it possible for two MCUs to monitor the same analog voltage signal?

In principle there is no issue provided the source can drive both inputs without excessive error. There are not a lot of valid reasons to do this in a new design (as opposed to something being tacked ...
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2 votes

How to remove noise in ADC voltage measurement?

You need an anti-alias filter in hardware You say Filtering/averaging is not an option However if you don't low-pass-filter in hardware at the Nyquist rate or lower, aliasing is going to seriously ...
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8 votes

How to remove noise in ADC voltage measurement?

A differential measurement still needs a ground reference point, due to how most ADC front ends/signal conditioners are designed. You need to connect the (-) side of the battery to both one analog ...
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4 votes

How to remove noise in ADC voltage measurement?

Question 1: I do not expect ground currents in your analog path that could mess up your readings. The ADC is at an end point of the supply path. Question 2 and 4: Yes, absolut possible. A series ...
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3 votes

How to remove noise in ADC voltage measurement?

Could the problem be caused by the grounds? Yes and the cabling could also do this. Current going back through the cable between the ADS and the PLC can cause voltage differences on ground. Know what ...
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20 votes
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What does a function mean that doesn't have "void", "int", etc in front of it mean?

The functions are interrupt handlers, defined using the ISR(vector, attributes) macro. The macro generates a proper platform-specific function signature, including ...
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