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I'm brand new to the Arduino world.
I'm interested in building an Arduino app such that when a button it pressed, the Arduino connects to WiFi and through this Wifi connection accesses a publicly-accessible Web API over HTTP. Accessing the API takes less than 1 second. After this, the whole system should go to sleep until the next time the button is pressed.
The tricky thing is that I want to power this Arduino with disposable (ie: non-rechargable) batteries -- either a single 9V battery or two AA batteries. But I don't know if this is feasible. How much battery power will be consumed by connecting to a Wifi Network? How much battery power will be consumed simply to operate the Arduino chip? Is what I'm suggesting feasible? Do disposable batteries pack enough juice to power this application for hundreds of button-presses?
Yes, you can power an Arduino with disposable batteries. If you want to minimize the power consumption, I'd recommend bypassing the onboard voltage regulator and powering the Arduino through its 5V pin using a switching or an LDO regulator like the LM2936 - these are very efficient and will consume very little power when the board is asleep.
You didn't say which Arduino you're using, or what you're using for wi-fi connectivity, so I can't answer as to what the power requirements of your device would be. But I don't see any reason it would be unfeasable to power it with AA batteries.
I'd recommend against using a 9V battery if long battery life is a consideration. Use AA batteries instead, if you have room. You'll need 4 of them (1.5V x 4 = 6V) because the Arduino needs at least 5 volts to run. But 4 AAs will have a much higher current capacity than a 9V, so they will last much longer.
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The Beacon radiates signal. A nearby Bluetooth enabled device receives this signal. When a particular application recognizes its signal, it connects it to an action or content track stored in the cloud and allows the user to view it. By editing the application on your phone, you can set how it reacts to signals.
For example:
Beacon systems are installed in the shops within a mall. All Beacons have their own fixed ones. When the signal of Beacon, which broadcasts with its own private ID, reaches your phone, the application of the shopping center (which should be pre-installed) will process this signal and give you outputs such as the store discount coupon, navigation proposal varying according to the application's program.
When I set out from this example, I have the following question in my mind. Why is BLE beacon technology used instead of Wi-Fi infrastructure (already installed in phone and mall)? When we periodically scan Wi-Fi signals, we can access SSID, MAC and RSSI information. When we use this information as a query tool by using an application, the approximation recognition with the beacon is completed. In this way, we do not have to invest in BLE beacon infrastructure. What is the keypoint of BLE beacon technology? Why do people need to use this technology?
The simplest answer is in the fact that BLE devices are extremely power conscious (therefore the name, Bluetooth Low Energy). A BLE beacon can run on a coin cell battery for a year or even more without any issue. This is a huge advantage over WiFi which is relatively considered power hungry. It is also an advantage over other low energy wireless technologies (e.g. ZigBee, ANT, etc) in that phones and tablets have Bluetooth built in and therefore do not require any extra hardware. There may be other minor reasons such as indoor performance and interference, but the Low Energy aspect is the main differentiator.
There are many articles that discuss this in length, I recommend the following:-
Comparing Low Power Wireless Technologies
BLE vs WiFi: Which is Better for IoT Product Development
The Pros and Cons of Bluetooth Low Energy
Finally, I recommend posting a similar question in the future to other StackExchange networks (e.g. ElectricalEngineering) as StackOverflow is mainly for programming related questions and you'd probably get more traction and better answers in other sites.
I hope this helps.
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I want to experiment with some sensors with my Raspberry Pi 3. For that, I searched for sensors to buy online. During the search some websites says "buy sensors for Arduino" and some says "buy sensors for Raspberry Pi". So. if I buy sensors for Arduino, will they work with Raspberry Pi or not?
'it depends" being the answer.
The short answer is: yes probably it will work on both.
The longer answer is you'll be doing some work arounds. (and each is case dependent).
For example the arduino has analog pins, but AndroidThings boards do not - you would need to use a Analog to Digital converter (like this or any other ADC).
Android Things supports these protocols & interfaces
- I2C
- SPI
- UART
- PWM
- I2S
If the peripheral uses one of these, then yes it will more than likely work an AndroidThings (a raspberry pi).
AT also supports GPIO. However if the sensor only uses GPIO, it is likely to require a fast communication speed (in the range of 10's of nano seconds), but Android Things GPIO is slow (the frequency is in the range of 300± nano seconds) - so you'll probably find these sensors are not supported on AT (a raspberry pi).
If after all that you buy a sensor and it won't work with Android Things - you can still use the sensor with an Arduino board and then control the Arduino Board with a Raspberry Pi as a master (like this).
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This will probably go -4 in seconds, but I'm genuinely curious and googling hasn't resolved anything.
My potential project:
Power on a device from my smartphone.
I know raspberry pi can do this, but as I was reading through Arduino docs it sounds like if you need a very basic command to fire/read then Arduino is your way to go. At this point is there any advantage in choosing an Arduino over a Pi3?
I know I'm ignorant, but I can't figure out why I would choose Arduino ever again.
Price: The cheapest Raspberry Pi is $5 USD but unless you happen to live somewhere that you can pick one up in person you're going to be paying at least that much again for shipping. Add another $1 for an SD card and say $2 extra for a power supply good enough to make it run reliably. You can buy an Arduino Pro Mini clone for about $1.57 with free shipping or a Nano clone for < $3 with free shipping, any power supply will work, no SD card needed. So you're saving at least $10 on each device you make. If you're already familiar with Raspberry Pi the extra expense may be worth it for the time you will save not needing to learn to use the Arduino.
Bare metal programming: There is no operating system to deal with on an Arduino. This simplifies things greatly and improves reliability. The lack of an operating system on the Arduino means you can easily get very precise timing when that is important, though likely this is not relevant to your current project.
Power consumption: It's possible to run at extremely low power consumption with an Arduino, especially if you make a few easy modifications to the circuit board (removing the power LED and voltage regulator). It is possible to reduce the power consumption of Raspberry Pi but I don't think you will ever get close to what you can do on an Arduino. This will be more of a concern for a battery powered application.
Size: This could depend on which accessories you need to attach to either board but lets consider the likely choice of WiFi as your method of communication between your phone and device. In the Arduino world the cheapest and easiest way to accomplish this would be to use a WeMos D1 Mini, which is less than half the size of the Raspberry Pi Zero.
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I wonder if is possible to adapt a low speed fault tolerant CAN network (100kbps) to a high speed CAN network. I need this to connect a newer infotainment board (CIC) to my K-CAN inside my BMW e60 car. I already managed to wake up and control (on a workbench) the CIC via Arduino and MCP2515 shield.
Do you have any idea if is possible ?
Thanks!
The easiest thing to do is probably to simply replace the CAN transceiver IC on the infotainment board you're putting into the car, to one that matches the bus type you already have in the car. The different transceiver ICs are usually drop-in replaceable, so no problem with that.
However, even with a matching transceiver, the data bit rate needs to match as well, so you need to determine the bit rate used by the board and the one used by the vehicle's bus.
If the bit rates don't match, there's no point in replacing the transceiver IC - in this case the only solution is probably to create a bidirectional store-and-forward adapter/gateway.
One may construct such a gateway using an Arduino, but it'd have to have two CAN bus "shield" daughter boards - one for each bus, where each daughter board carries a CAN transceiver appropriate for the bus it'd connect to, and its CAN controller configured to the appropriate bit rate.
Each of the CAN controllers connects to the Arduino via SPI. It is very much possible for multiple slave devices to share a single SPI bus, with the master device (e.g., the Arduino microcontroller) selecting the device it wishes to communicate with using the chip/slave select (CS/SS) lines. For more information about SPI communication, including multi-slave, see here and here.
For off-the-shelf Arduino "shields" relying on SPI, additional shields (beyond the first) might requires physical rerouting of their CS/SS line to a different control line coming from the Arduino microcontroller, to allow slave selection. Consult the boards' pinouts and/or schematics to determine which modifications are required. Specifically, if using seeed's CAN bus circuit, check the "CS pin" section of its Wiki.
In terms of software, the gateway would basically need to constantly copy messages received in one bus to the other, with a small FIFO buffer to keep a few messages in case the target bus is busy.
Some modifications to the CAN bus library's source code might be required, to support multiple CAN controllers and switching between them using the CS/SS lines.
BTW, Stack Overflow is probably the wrong place for this question, as it's not really a programming question.
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I am a software developer with no prior experience in embedded programming. I have to develop a prototype project:(example) to generate Morse Code pulses which are to be output through a solenoid in the form of vibrations. I found that either Arduino Nano or Micro will do this job. Though I have choosen Uno for the project keeping in view later requiremenst will evolve.
I found Leonardo & Uno two close varianst. I selected Uno based on some research I did. Mainly I learned Leonardo is not good choice for beginners due to some of its problems and/or features. Uno also has more help available too being a seasoned variant.
It will be nice if I can have some opinion about it.
As you and Keshav Saharia said, assuming that the capabilities of Uno and Leonardo both meet your needs, the reason to choose the Uno is because it is older, more mature, and better supported. For example, most of the Arduino posts here and on EE.SE are either based on Uno or are compatible with Uno. Likewise, most of the Arduino guides work out-of-the-box with Uno, but not necessarily with Leonardo; Leonardo is always one of those footnotes: If you have Leonardo, you need to do this other thing instead.
Also, if, at some point, you decide to ditch Arduino and use a bare ATmega chip, ATmega328, the MPU in the Uno is the one you are likely to use, and also the one more people are familiar with. Leonardo uses a different AVR chip, the ATmega32u4, which, like the Leonardo, is not quite as popular (widespread?). These are good reasons to choose the Uno, as far as I am concerned.
On the other hand, if you are hoping to keep the prototype board for yourself, you might want to think about the Leonardo, since it is more powerful: more IO, second hardware serial port, etc.
You already asked this question and it has been answered. Your conclusion that the Arduino Nano or Micro won't do the job is wrong. Any version of Arduino will work, as will any other microcontroller (Basic Stamp, Picaxe, etc.). All you need to do to control a solenoid is to turn a digital pin from LOW to HIGH. You WILL need some external circuitry because of solenoid power requirements but the circuitry is trivial.