I am using the Arduino Wifi Shield and Arduino Uno board. Yesterday i had stack 2 wifi shield without the Uno by accident and have powered it with a 9V battery, after that when i tried to use either one of the wifi shield, it seems that it wouldn't work anymore, e.g the led on the side of the shield won't turn on. I have been troubleshooting but now i am thinking i spoiled it by stacking them. Can anyone clarify? Thanks.
I am also using a seven segment in my project that includes the uno and wifi shield. When i use the usb cable the seven segment, the seven segment is dimmer which is perfect but when i use 9v battery it seems to be brighter and the result is the same when i use a 5v power supply. The usb provides a voltage of 5v but why is it different from a power supply of 5v?
Can anyone help me answer this 2 questions?
I think that the WiFi shields don't support 9V, and one of them died, fortunately shorting the battery and saving the other one.
Please look at the data sheet, for the voltage and current of these shields. Most probably the USB port doesn't supply the required current, so that the voltage breaks down to something below 5V.
Be more careful with powering all the modules, or you'll risk more killed boards.
DrDiettrich:
I think that the WiFi shields don't support 9V, and one of them died, fortunately shorting the battery and saving the other one.
Please look at the data sheet, for the voltage and current of these shields. Most probably the USB port doesn't supply the required current, so that the voltage breaks down to something below 5V.
Be more careful with powering all the modules, or you'll risk more killed boards.
Hmm but to power the Uno, i would require the 9V to power it, it is possible right, with the WiFi Shield Stacked on the Uno? Then it seems odd as both doesn't seems to work. It was a pretty bad day for me to be honest, plus my submission for this project is end of next week. I don't really know what's wrong with the wifi Shield and seven segment or the power supplied... But thanks so much for answering..
The Arduino boards include an voltage regulator, which supplies proper power not only to this board, but also to all connected shields. If you supply power directly to any shield or module, consult its data sheet first. Some boards require 3.3V, others 5V. A higher voltage will kill the board, as you noticed already.
DrDiettrich:
The Arduino boards include an voltage regulator, which supplies proper power not only to this board, but also to all connected shields. If you supply power directly to any shield or module, consult its data sheet first. Some boards require 3.3V, others 5V. A higher voltage will kill the board, as you noticed already.
I see..however i can't find the data sheet for the wifi shield..but it did say "Operating voltage 5V (supplied from the Arduino Board" so does that mean i will have to use a 5v battery instead? I think i have killed both shield so i will have another one to test out with 5V tomorrow. Thanks.
Is it safe to say that 9v is too much for the 7 segement as well?
I strongly suggest to keep your hands off electrical devices without data sheets.
DrDiettrich:
I strongly suggest to keep your hands off electrical devices without data sheets.
But there is no datasheet for wifi shield isn't it? Well i can't really keep my hands off since i am needed to complete the project. It's ok if u can't help but thanks anyway...
WiFi shields use a lot of current, and it is not a good idea to use two of them with an Arduino as the voltage regulator may burn out.
Also, the rectangular 9V batteries used in smoke alarms can't supply enough current for an Arduino with even one WiFi shield.
jremington:
WiFi shields use a lot of current, and it is not a good idea to use two of them with an Arduino as the voltage regulator may burn out.
Also, the rectangular 9V batteries used in smoke alarms can't supply enough current for an Arduino with even one WiFi shield.
Thanks for replying, however i am only using 1 wifi shield, and i am using a rectangular 9v energizer battery used in smoke alarms, so may i know what do you suggest for me to power this circuit/project?
Use either a 9V wall adapter, capable of at supplying least 1 ampere, or 6 AA (or larger) batteries.
jremington:
Use either a 9V wall adapter, capable of at supplying least 1 ampere, or 6 AA (or larger) batteries.
hmm thanks for the help but it will be hard for me to do either that since it should be a portable device so wall adapter is out of the question.. as for the 6 AA batteries, it might be possible but i will have to get a larger box to place the circuit and board in. I will think it through.. Thanks again for the help.
How long do you want this device to run? You might get a couple of hours with AA batteries.
jremington:
How long do you want this device to run? You might get a couple of hours with AA batteries.
Well i will need to do a short demo for my supervisors to see, so just less than a day or just 5 minutes or less. Seeing the required size of the box, the most AA batteries i could squeeze in is probably 3. Thanks!
3 AA batteries provide about 4.5V, which are sufficient for the Uno. When your WiFi device runs on 3.3V internally, it should be happy with that voltage as well. Then the question is the voltage regulator, that reduces the input voltage to the internal 3.3V. When the board includes such an regulator, it should be sufficient as well. Otherwise you have to add such an regulator yourself, or try to connect the module's 3.3V pin to the lower 2 cells, supplying about 3V:
5V --- AA --- 3V --- AA --- AA --- Gnd
When you use an voltage regulator to supply 5V, then 4 or 5 cells should be sufficient (6V to 7.5V), or (better) some rechargeable battery of a similar voltage. Step-down regulators are available for 6V (or more) to 5V, while the Arduino on-board regulator requires at least 7V input for proper operation.