EternityForest
  • Member for 9 years, 2 months
  • Last seen more than 5 years ago
Maximum I2C Bus Length?
25 votes

The insane sounding lengths like 10,25, and 100m are perfectly possible, and I use the method often (with UART not I2C, but the method stands) when I need to put stuff together quickly. It's not ...

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Sending I2C reliabily over Cat5 cables
7 votes

I2C is not the way to go. CAN trancievers cost a dollar each, and you can use them as uart trancieves and write your own protocol so you dont need a can compatible micro of you dont want to use the ...

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Why 2.4 GHz Band?
3 votes

As others have said, it's an ISM band, and all of the other listed reasons are totally valid, but I think another part of of the reason it's more popular than other ISM bands is that it is available ...

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Connecting phone chargers in parallel
3 votes

The voltage drop in the diode will make the voltages in the two chargers unequal(as if they already weren't), and one charger will probably carry more current than the other, that one will hit its ...

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How do I get 12V 260mAh from 4x 6V 130mAh solar cell panels?
2 votes

Simple answer: two in series make 12v, two in parallel doubles the current. The more involved answer is that for the cost of 8x AA nimh cells you could probably get 1 small(5ah or so) lead acid ...

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Can AC current be switched using SPST EM-relay controlling "live" wire alone?
2 votes

This is exactly the right way to switch AC with relays , but do keep in mind the current rating of you io pins . The relay coil can use a fair amount of current. Also, it is what we call an "...

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Voltage Regulator: how to compensate for voltage drop in cable?
2 votes

What I would most likely do is just put a powered hub as near to the load as possible. Or if it's just for a charger, and you want a low voltage run for some reason, run a 12V cable(Use some speaker ...

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Running CAN bus with RS-485 transceiver
1 votes

Somewhere I heard that some of the earliest CAN applications used rs485. Not sure if modern CAN is still compatible but on the surface they look similar. The issue I see is that the RS485 transceiver ...

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Voltage regulators
1 votes

Capacitors between a power line and ground are like water towers, they provide the extra energy that a circuit might need for a few micro seconds, so that when the current the circuit uses changes ...

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Is there such a thing as a switch that can be actuated automatically?
1 votes

It might be possible to make one with a solenoid, but that sounds like a lot of work. You could fake it with a momentary toggle switch that returns to the center, and put an LED above and below it, ...

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Why IC 4081 is taking 2-5 seconds to set the output to low
1 votes

To add to Wouter's answer, I would guess that the either the chip or some dust or oil or dirt on the chip has a tiny bit of internal leakage which is equivalent to a pull down resistor of several ...

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Read Arduino pin from another Arduino
1 votes

Normally, this should work exactly like you would think, and nothing will be damaged. However, some people choose to put a resistor between the pins, just in case a programming error should ...

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Is an Arduino Uno capable of running 24/7?
1 votes

The Arduino was designed for prototyping but gets regular use in art installations and other 24/7 applications. There really isn't anything to wear out under normal conditions even running for years. ...

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Best way to reduce battery consumption for LED device?
1 votes

A trick I really really like is to let the user decide when he needs to know the status be having a pushbutton for status display. This does not work if you need "at a glance" visibility of the status....

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i2C : pull-up resistors "design pattern", Shielded cable and connector?
1 votes

i2c does have multi-master, 4x 4.7k would be about 3mA or so at 3,3, which could be a problem for some i2c chips but not many. The RasPi uses 1.8K pullups and they don't seem concerned with sink ...

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cable losses per meter (voltage > 400 and frequencies [50 Hz ... 60 Hz])
1 votes

Dielectric loss is an AC concept. It sounds like you are dealing with RF current, which is bound by much more complicated laws than DC. Ohm's law only tells a very small part of the story once you ...

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Is it possible to use a lead-acid battery as a power bank?
0 votes

6v is so close to 5V that a linear regulator will usually be about as good or better than a fancy switcher. A simple lm323 regulator is rated for 3A max the 323 does in fact need more than 6v and won'...

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Stiff, straight wire similar to LED legs
0 votes

Are tinned music wire shafts as used in lure making solderable? They should be if it's really tin. They sell them on eBay pre straightened in 0.045 inch by 13 inch. I think they are spring steel and ...

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Design considerations for powering microcontrollers with a 100 m cable
0 votes

On eBay, there are regulator boards that take up to 42 volts and have an adjustable output. They are about one inch by two inches and cost $1. They seem fairly reliable too, as long as you look at the ...

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Is it possible to make a usb charger to power multiple devices?
0 votes

A USB charger is not just a simple 5v supply and connector. The charger has to tell the device how much power there is. I believe that normally they put a resistor between the data lines. But for the ...

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Detect multiple corn bags through wood with a sensor
0 votes

To detect bags resting on the surface, I would wonder about piezoelectric impact sensors, or about putting some ferrite beads in the bags and putring coils under the wood to detect inductance change. ...

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Is it possible to run a photodiode plus op amp on a 3V battery?
0 votes

Heck, I've seen photodiodes directly connected to a DIGITAL IO pin used to measure the ambient light(I don't think it was accurate but it told you if the lights were on) by using the photocurrent to ...

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Control resistances with voltage
0 votes

Definately not the best way to make a VCO. But, the question deserves an answer, because it's an interesting and possibly educational way to do a VCO, and voltage controlled resistors are used for ...

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Switch that can be remotely switched
0 votes

I would actually suggest a momentary toggle, but with one LED above and one below the switch, to recreate some of the up/down/toggly feel of a toggle. I'd still want them to be different colors though....

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Piggy-backing off power amplifier outputs
0 votes

What you actually want is to reduce or attenuate the voltage down to headphone levels. A voltage divider(or L-Pad as audiophiles call them) will do that just fine, and only needs two resistors. The ...

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