this is my first post in this community so please be patient with me. I'm new to the arduino-stuff and i have a litte project im working on.
I want to power a motor (Nema17) a pump (12v) and the arduino mega 2560 (with an Touchdisplay-shield) by a notebook powersupply (15V ,max 5 amps). The wiring and coding is working fine, but right now the arduino is still powered by the USB-connector. I know i can use the Vin-pin to power the arduino, but im not sure, if the 15V is too much for the arduino and will destroy it, furthermore im not sure how to wire/connect it to the powersupply.
im sorry for my bad english.
I hope someone can give me some advise.
Thank you.
15volt is in the danger zone for a Mega, especially if you want to draw some current from it (the shield).
Better use a buck converter between that 15volt (19volt?) supply and the Mega.
Adjust it to ~7.5volt if you are connecting it to V-in, or adjust it to 5volt for connecting directly to the 5volt pin of the Mega.
Leo..
Kassiopeia:
I know I can use the Vin-pin to power the Arduino, but I'm not sure, if the 15V is too much for the Arduino and will destroy it
Essentially, wrong on the first point. You misunderstand the "Vin" pin or "barrel jack" on the Arduino.
It is nothing more than a novelty included in the older Arduinox when a 9 V "plug pack" was a common object which could be used. Unfortunately, when these were nothing more than a transformer, rectifier and capacitor, their regulation was terrible and lightly loaded they might well produce more than 12 V.
It could be used to demonstrate the Arduino with a couple of LEDs connected, drawing no more than 60 mA or so. but the on-board regulator has virtually no heatsink, so will overheat and shut down if more is drawn. And at 12 or 15 V, it would be generating even more heat, so may not even be able to support the Arduino itself.
Please consider the "Vin" pin or "barrel jack" as nothing more than a decoration. For any serious project, you need to provide a regulated 5 V supply to the "5V" pin. If the total current draw will not exceed 500 mA, you can power it via the USB port - a "phone charger" with a USB connector is a quite inexpensive and readily available such source (but I would not recommend purchasing these through eBay).
If you have a 15 (or 19) V supply, the switchmode "buck regulator" modules available on eBay are the way to go to get your 5 V.
Alternatively do the sensible thing and use a cheap LM2596 buck converter set to 7.5V output or so to
power the Arduino's barrel jack, allowing the on-board regulator to produce a clean regulated 5V without
switching noise on it.
If you are doing anything with sensitive analog sensors, or audio, using the on-board regulator will reduce
the amount of noise on the 5V supply nicely. This gives you a second line of defence from noise and spikes
on the main power supply.
In the industry this is called point-of-load voltage regulation and it standard practice, not novelty.