Using multiple shields

Hi. New to arduino here.

Can I stack multiple shields on an arduinio board? I have bought an mega2560 board + TFT LCD Board + Touch Screen SD Reader (http://www.ebay.com/itm/301834280329?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT). But it would be also nice to give it wifi capabilities.

So, how can I know if wifi shieds on the market are compatible with the board + shields I allready have? Can you recomendo an wifi shield for me?

If I can't use a wifi shield with my system, is there another way to conect my board via wifi?

Thank you!

, is there another way to conect my board via wifi?

ESP8266

uderman:
Can I stack multiple shields on an arduinio board? I have bought an mega2560 board + TFT LCD Board + Touch Screen SD Reader (http://www.ebay.com/itm/301834280329?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT). But it would be also nice to give it wifi capabilities.

So, how can I know if wifi shieds on the market are compatible with the board + shields I allready have? Can you recomendo an wifi shield for me?

If I can’t use a wifi shield with my system,

Yes. The whole concept of Arduino is based in stackable shields in combination and one should simply go between your Mega and the display. Any WiFi shield manufacturer who made a shield you couldn’t use would be quickly out of business. You can stack as many shields as you can sensibly provide power to. Four would be common.

Ty all for the answers.

Nick_Pyner:
Yes. The whole concept of Arduino is based in stackable shields in combination and one should simply go between your Mega and the display. Any WiFi shield manufacturer who made a shield you couldn’t use would be quickly out of business. You can stack as many shields as you can sensibly provide power to. Four would be common.

@Nick_Pyner,

I understand shields can be stacked, but only if they don’t use the same arduino pins, right?

I understand shields can be stacked, but only if they don’t use the same arduino pins, right?

Absolutely !
Another thing you need to consider is the amount of power your shields will drain from the 5V arduino regulator !

Some pins should be in common:
+5V, +3.3V, GND, VIN, Reset

Some pins can be in common and used by both for I2C: SCL, SDA, as long as the shields have unique I2C addresses.

Some pins can be in common but need some uniqueness for SPI: SCK, MOSI, MISO, but need unique pins for Slave Select. Pin 10 needs to be an output on the Arduino if it is to be SPI master; pin 10 can be Slave Select to one of the shields.

Some pins can be in common if only one of the multiple boards uses the pin as an output and the others use it for an input. For example, if the Arduino is sending data out over serial and the slaves are all listening/monitoring it.

If the shields have output pins that cannot be disabled, those pins need to be unique.

uderman:
@Nick_Pyner,

I understand shields can be stacked, but only if they don't use the same arduino pins, right?

Read CrossRoads, not rmartins. Plenty of pins may be common and boards that are power-hungry are likely to have their own regulators, or even their own power supply. Shields typically have a full complement of pins but few are used, they are mostly pass-through, in order to maintain the system.

Nick_Pyner:
Yes. The whole concept of Arduino is based in stackable shields in combination and one should simply go between your Mega and the display. Any WiFi shield manufacturer who made a shield you couldn't use would be quickly out of business. You can stack as many shields as you can sensibly provide power to. Four would be common.

That's not been my experience. I've found that most shields have components on them that are too tall, or have connectors or other important things on them like antennas or displays that are blocked if another shield is on top. Also very few shields have jumpers for pin selection to prevent pins from different shields being connected together inappropriately.

aarg:
That's not been my experience. I've found that most shields have components on them that are too tall, or have connectors or other important things on them like antennas or displays that are blocked if another shield is on top. Also very few shields have jumpers for pin selection to prevent pins from different shields being connected together inappropriately.

Sounds like bad luck, and very bad planning. If you want to put a shield on top of a display shield, I guess you deserve all the grief you are sure to get - part of that being finding a display with female headers.. And I suspect that those shields that need jumpers usually have them. Some have quite a lot. If you are short of height, you can always get a set of headers and, if you are seriously short of height, you can get headers with seriously long pins.

Nick_Pyner:
Sounds like bad luck, and very bad planning. If you want to put a shield on top of a display shield, I guess you deserve all the grief you are sure to get - part of that being finding a display with female headers.. And I suspect that those shields that need jumpers usually have them. Some have quite a lot. If you are short of height, you can always get a set of headers and, if you are seriously short of height, you can get headers with seriously long pins.

I grant you that the display example is unique, obviously it is mandatory that it be on top by design. But the bad planning is not mine. I never had the consequences of bad luck from lack of planning with using shields, because I scope them out thoroughly before I purchase them. Consequently, a lot of ideas I have had for stacking shields were not implemented - instead, I used external modules and connected them with wires.

It is quite common to see shields with fixed pin assignments. From time to time you will see threads here where someone is having problems with them, often the advice involves cutting traces and rerouting with jumper wires.

I totally agree that shields should stack painlessly, I'm just saying that many, many of the shields that are available, don't. That's not my failing. How many shields actually make use of the end space that is not blocked by the connectors to locate connectors and LEDs where there is no interference? Very few.