(04-14-2016, 03:42 AM)BnEc Wrote:(04-14-2016, 03:37 AM)DaveyDarko Wrote: Make sure you are getting enough power, I could foresee a scenario were the WiFi/BT module is drawing enough that, when added to the rest of the boards load, might overwhelm your supply and thus fail. Just a thought before sending it back.
Hi Davey,
Thanks for the reply, I'm currently using a 5v 2.4A power supply, as I have been struggling to get any joy with anything lower. I'll have to have a look around and see if I have a larger 5v charger.
It is not uncommon for wifi to have brief moments of high power load (like when sending files, negotiating with an AP or even searching for one). It sounds as if this is what is happening to you. I know on my Pi2 I can idle around 400ma used but if I try to send a large file I can push power usage to 2A really fast. And for many cheap power supplies the more current you draw the more the voltage sags. It is not uncommon for something that is capable of 5.0v at 100ma to drop to as much as 4.4v at 2A. Thats a crappy supply, but believe me they are out there. Of course when the voltage drops, chips sensitive to that may freeze, reset, or just act erratically. And this isnt limited to just wifi, every sensor, screen, usb device you add increases this drain. it only takes a heavy load on the usb bus seconds to drop voltage with a cheap supply and reboot a board.
You can use any power supply that is 5v with a current rating 2A or more. The 5v cant change but the current could be as much as 50A available.
Chargers are not the same as power supplies. Most are engineered for short duty cycles instead of constant load and usually have very poor heat dissipation and to be frank most arent meant to live for more than a year or two. Once phone chargers crossed the 1A boundary they got very proprietary. Since the Usb 1.0 spec current max is well under 1A most phone chargers will not put out more than 500ma without getting a manufacturer specific signal. For some its as simple as a pull down resistor, for others its complex communications. In short, I wouldn't use anything that is is not meant to be a power supply.
What I personally am using is a power supply adapter board with an old router wall wart supply that outputs 12v at 2A. ( this http://www.aliexpress.com/item/Free-Ship...11454.html ) Of course ordering from Aliexpress takes a bit longer but the same board should be available in many places, Amazon, Ebay etc. just keep in mind not every LM2596 board works as well as the next. Some designs suck. Also use caution with adjustable output boards that have a usb connection since you can easily set the USB port to a voltage high enough to fry anything you connect. An old laptop supply, or any DC output wall wart with a voltage of say 7v at 2A can feed one of these adapters (up to its rated input voltage, read the specs these vary).
There are good usable supplies out there but despite the many anecdotal "I used the charger for phone X to power my X for years" stories out there, save yourself trouble and buy a good power supply. If in doubt, just pick a reputable dealer like Farnell, MCMElectronics, etc and buy something at the voltage you need with more current than you need.
