I have an arduino UNO and I'm looking to trigger the start of the main code bloc using wireless buttons. I also need to print on a wireless lcd. I have been looking at various shields for bluetooth, rfid, wifi etc. The range of communication isn't particularly important now as I'm simply doing feasibility project. In the future the range will be around 100m.
When you purchase a shield do you have to buy additional pieces to actually make the shield come to life?
Do you need two UNO's, two shields and two chips to make the wireless communication work?
amhenderson:
I have an arduino UNO and I'm looking to trigger the start of the main code bloc using wireless buttons. I also need to print on a wireless lcd.
I don't think there is such thing as a wireless LCD but any LCD can be installed on a wireless-equipped Arduino.
I have been looking at various shields for bluetooth, rfid, wifi etc. The range of communication isn't particularly important now as I'm simply doing feasibility project. In the future the range will be around 100m.
Bluetooth is only good for about 10m or so and you are probably wasting your time trying with it. Also, there isn't much information around on Arduino to Arduino comms by bluetooth. This is probably because it is hard and not a very good idea. There are other wireless systems like Xbee that are more suitable but you might think about whether you really need Arduino to arduino communication. It can be easier and cheaper to have the Arduino talk to PC, laptop, or phone. I suspect this would particularly apply over the distance you have in mind.
When you purchase a shield do you have to buy additional pieces to actually make the shield come to life?
Typically a shield is a shield because you plug it in and go. At most you also connect the peripherals it is intended for, like plugging motors into a motor shield etc.
Do you need two UNO's, two shields and two chips to make the wireless communication work?
By chip I assume you mean a communications module but no anyway. See above.
You can try two xbee's...the kit I got had a ttl-USB converter on the adapter board so there was no need for another arduino to communicate with the computer.
amhenderson:
I have an arduino UNO and I'm looking to trigger the start of the main code bloc using wireless buttons.
Perhaps you could use an infrared sender / receiver for the wireless communication. The advantage over a RF approach is that with IR you could potentially just use an existing TV remote control handset, or something derived from it, and wouldn't need all the complexity of Arduino, RF transceiver, packaging this with its power supply, etc.
If you do try an nrf24l01, get one with an aplifier and a decent antenna. The ebay-modules I have with pcb antenna won´t reach 100 meters (not even at lowest baudrate with lots of retransmits). The ones with amplifiers and good antennas reach a lot further, I only use it through a few walls, about 15m distance only, but it´s good for that, which makes me think 100m in "open air" would be no problem. More expensive but worth it.
The rf433 modules reach a bit further than the nrf24l01´s with pcb antennas but 100m is difficult with the ebay modules I bought from china.
(433 mhz have longer range, but in order for it to reach 100m I had to get one with a proper antenna and an encoder and a receiver with a good antenna and a decoder (it basically drives a few pins either high or low, so it´s no good for transmitting data, but works ok for "status messages") the one I got claims to do 4km in what I suppose is "thin air" )
I just built an automate light switch with the nRF24l01 modules as mentioned above. They work well and theres a lot of support out there for them but range is weak. It sometimes has trouble with only one wall and a 5m hallway. I would recommend the RFM12B module, its still cheap and has a much greater range. Stats say 300m, we'll see about that. The moteino board mentioned below incorporates that same module. Seems like a good fit for the project.
I got a 315 MHz RF Wireless modules. Not shields, just the modules. But the hardware interface couldn't be simpler. I wired it up and ran the programs during "hack night" at the local hackerspace. It did fine for about 10 feet, but couldn't receive data across the room. The modules cost about $1 for the receiver, and $.90 for the transmitter.
Next day I attached a couple of wire whip antennae. Basically 27 cm lengths of hookup wire. I wanted it for a mailbox detector, and the mailbox is about 150 feet from the house. I was hoping to get it to send at least to the house. I thought maybe I could put the receiver on the inside wall closest to the mailbox. I was surprised when I went into the back room where the receiver was running, and it was scrolling away. So it's receiving fine through 170 feet of air and two walls and a bed. I haven't tested it to see if it will reach 100 meters, but I haven't tried maximizing the antenna orientations or adding ground planes or anything else, either. It is already exceeding my needs.
I understand 315 MHz is longer wavelength than the 2.4 GHz modules, or even the 433 MHz modules. That means it will go farther through air and walls but you get lower data speeds and the antenna has to be longer.
I use an ATtiny85 for the transmitter. The hardware hookup is very simple. The software--not quite so simple. I used the RCSwitch library but had to modify it to send the data I wanted to send instead of "switch on" messages.
The nrf24L01 modules look like the best solution. I have found some tutorials on how to connect the pins to the arduino. Does each of these nrf modules require an arduino?
amhenderson:
I have an arduino UNO and I'm looking to trigger the start of the main code bloc using wireless buttons.
Perhaps you could use an infrared sender / receiver for the wireless communication. The advantage over a RF approach is that with IR you could potentially just use an existing TV remote control handset, or something derived from it, and wouldn't need all the complexity of Arduino, RF transceiver, packaging this with its power supply, etc.
Good thinking, but....OP stated final range will be approx 100 metres. I don't know any IR solution with that kind of range. Plus...it would have to maintain line of sight.
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