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Project Guidance / Re: Adapting a sketch - dairy ...
Last post by wvmarle - Today at 05:36 am
This feels like one of those projects that begins with "All you have to do is...."
All we need is ...
You were really close :-)
Please provide convincing evidence that the file contents are not correct, and post relevant code.
You could do it yourself but it would be easier to search for and use the Bounce2 library.
What you want to do is possible BUT the voltage on the pin must NOT exceed the voltage supplied to your unspecified Arduino.

A pin can:
> Output a LOW (ground)
> Output a HIGH (3.3 volts or 5.0 volts depending on the Arduino)
> Output a HIGH through a series resistor of about 50 Kohms by setting to INPUT_PULLUP
> Appear to disconnect by setting to INPUT (which is not truly disconnected but the input impedance of several Megohms is very very close to being disconnected)

The setting of a pin to INPUT or OUTPUT is usually handled in the setup() function.  If you change the setting of a pin between INPUT and OUTPUT in the loop() function, then your comments better explain this completely and carefully.
General Electronics / Basic electricity
Last post by Paul__B - Today at 05:23 am
I have an external limit switch, that when pressed, will pass 12V.  When not pressed, it passes 0V.
Not good enough!  :smiley-eek:   From your further description, the limit switch actually disconnects the motor when pressed, so you need to explain why it "passes" 12 V when pressed.  So you actually need to show us (as described in the instructions for posting images) a complete circuit diagram of how the motor and switch are wired.

My last attempt was to connect the 12V lines (Pos. & Neg. ) from the switch to a ACS758 board and the corresponding vcc, grn, output to Arduino.   I got nothing of value on the Arduino analog pin... and the motor attached to the limit switch continued to run when the limit switch was pressed.... when prior, it stopped running as it was supposed too.
The ACS758 is a current sensor; connecting it in parallel across a switch will effectively short circuit the switch preventing it from turning off.  You could use it in series to determine whether the motor was running or not, but that would still not tell you whether it had stopped due to the limit switch or any other control.  Unless you provide a complete circuit diagram of how the motor and switch are wired, we cannot advise on how to correctly sense the specific operation of the limit switch.

A more detailed description of the purpose of your complete system would also assist.  This begins to sound like an XY problem:smiley-eek:
Hi, Hopefully this is a simple issue.

I'm using a Real Time Clock to awake a Mayfly data logger from sleep. Using the code at this website:

I'd like the code to wake every 15 minutes and record data on the 0:00, 0:15, 0:30, and 0:45 marks. I can acheive this just fine with the code above by adjusting (currentminute % 2 == 0)  to (currentminute % 15 == 0) from the code above (Line 65).

The problem is, when I do this, the Arudio wakes up EVERY minute and checks the time. I could perhaps set it to wake up every 5 or 15 minutes, but my fear is that it may wake up on the 0:01, 0:16, 0:31, 0:46 minutes for example, and the modulus test won't work.

Any suggestions on modifying this so the timer doesn't wake up the Arduino every single minute?

Project Guidance / Re: rtc to replace an arduino ...
Last post by wvmarle - Today at 05:21 am
You don't have to read an input for a pin to be an input. Upon startup all pins are set to input, high impedance, effectively disconnected from the circuit.

Then to ground it, simply set it to output, which unless set otherwise will be low.
Project Guidance / Re: What kind of components fo...
Last post by wvmarle - Today at 05:18 am
As I understand from your description you expect that the transmission of the beam that goes through the sample changes over time, right?

The first major problem with this whole setup is that your light is on for just 25 us. That's too short for the Arduino to measure as an ADC measurement takes about 100 us, and that is excluding time the ADC needs to charge itself and settle to the voltage it has to measure. So indeed you'd have to connect both LEDs to a peak detection circuit that holds the peak long enough for the Arduino to measure (holding for a few ms is already enough). The pulse is simply way too short for an ADC to measure - just about any ADC - unless you find one that can do a 10 us sample, so sample at 100 kHz.
Product Design / Cable Tester with remote
Last post by EnhanceAutomation - Today at 05:14 am
Hi I am looking at making a cable tester with the function of been able to test cables up-to 32 pins. We also want it to be able to test a cable remotely.


Cable installed where both ends can not be brought together to the tester. We were thinking maybe a arduino in the Master and one in the remote.

I have seen many ideas posted about thought the net on testers thought lets try here.

We would look at having a screen and be able to select the type of cable to test.

Be interested in peoples ideas on code & best board to use.
Project Guidance / Re: servo and mosfet
Last post by Wawa - Today at 05:14 am
Bottom line is that you can't use an n-channel fet (FQP30N06L) to switch high-side (the supply wire).
At least not without additional circuitry.
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