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what's your recent fail?
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Ice-Tea:

--- Quote from: exe on April 29, 2021, 03:19:38 pm ---...(but in weird qty of 24)...

--- End quote ---

Tube?
galvanix:

--- Quote from: WattsThat on April 29, 2021, 03:01:05 pm ---FWIW, TPS65253RHDR DigiKey has 4300 pieces in stock.

I’m putting in an order tomorrow. Can post them in a padded bag to Germany for cheap if it’s just a couple of pieces.

--- End quote ---

Thanks for the offer, but I actually had a typo in the part number. I was looking for a TPS652353 which is a voltage regulator specifically designed for universal LNBs. I wanted to make my own LNB bias tee for receiving the QO-100 amateur radio satellite using off-the-shelf universal LNBs.
josh132:
cap in reverse polarity.
AndrewNorman:
Getting 5V and 12V power supply outputs mixed up when playing with a LED/resistor pair to test brightness.

One very bright followed by one very dead LED later.
mindcrime:
As part of this reflow oven project, I bought an Adafruit MAX38556 breakout board for reading temperatures from a thermocouple. Last night I broke that out, soldered the headers on, and jumpered it to an Arduino and loaded the sample sketch. And BOOM, I got temperatures.

In Celsius.

I live in the USA. To us, Celsius barely exists... it's some weird abomination that's used by people from weird places like the UK, Europe, Australia, etc. So of course being the flag-waving nationalist that I am, I just had to convert the temperature to good ole Fahrenheit. So I wrote code that looked something like this:


--- Code: ---Serial.println( ( maxtemp.readCurrentTemperature() * (9/5) ) + 32);

--- End code ---

And none of the numbers that got displayed looked right. The thermocouple was apparently reporting the ambient temperature in the room as off by about 10°. Moving the thermocouple tip close to a lightbuib had the effect of sending the numbers higher, but still off by quite a bit.

Does everybody see my mistake? It's subtle in a sense, but very obvious in another sense.


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The problem is integer division. Dividing an integer by an integer (9/5) yields an integer (1). To get the expected value there [1.8] I had to either make one (or both) of those literals a float, or cast one of them to float during the calculation. The easy fix was just to change that expression to (9.0/5.0). D'oh.


And of course I'm just kidding about the nationalist bit. But an (unfortunate?) side effect of having lived in the USA my whole life, is that using Fahrenheit does, indeed, come much more naturally to me. So when it comes to recognizing something like, say, the ambient temperature in the room, I can only really process something like that in F° without jumping through hoops to do conversions.

When implementing the reflow oven, I expect all the temperature stuff will be done in C° as that's probably how the solder paste manufacturer specifies their temperature profile.
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