for my project (LED lights) I need a 12V power supply. I also plan to power arduino uno board with the same voltage through the connector. My question is, a few threads here mention 12V to be a "limit" voltage and potentially needing a heatsink. I only plan to use the Arduino for SPI control of the LED stripe plus powering one temperature sensor + an LED. So I guess that the current draw @5V is not going to be more than 200mA. Would this be OK for a 24/7 operation?
Also, if not, is there any point on using a simple voltage divider (maybe down to 8V) to burn off the excess energy and "help out" the regulator? If so, what would be the most appropriate resistor sizes?
for my project (LED lights) I need a 12V power supply. I also plan to power arduino uno board with the same voltage through the connector. My question is, a few threads here mention 12V to be a "limit" voltage and potentially needing a heatsink. I only plan to use the Arduino for SPI control of the LED stripe plus powering one temperature sensor + an LED. So I guess that the current draw @5V is not going to be more than 200mA. Would this be OK for a 24/7 operation?
Yes that should be fine. The problem with running at 12vdc Vin value is if you utilize the shield 5V pin to supply too much current for external circuitry, or run too many digital output pins at high output current the 5 volt regulator has to dissipate more and more heat. I ran my first serial arduino board for a long time on a regulated +15vdc lap top power module with no problems, and while the regulator did run pretty warm at times it never shutdown due to auto over temp or current protection limits being met.
Lefty
Also, if not, is there any point on using a simple voltage divider (maybe down to 8V) to burn off the excess energy and "help out" the regulator? If so, what would be the most appropriate resistor sizes?
If you have a few diodes laying around, you can put 2 or 3 in series to the arduino connector. Each normal diode will drop about .7 volts, getting you down a couple volts, keeping your onboard regulator cooler. If you want the very best voltage into the onboard regulator it would be about 7 volts. But in most cases, it is not that critical.
But be aware, not all 12 volt power supplies are 12 volt. So you will want to use your volt meter to test it and see what is really provided.
