Skip to main content
12 votes

How to get HTTPS on Arduino?

(Disclaimer: I'm actually the author of the evothings.com article) The Arduino UNO is more than capable at doing TLS. I've just finished up a blog post series on the topic. I have a working example of ...
Aaron Ardiri's user avatar
7 votes
Accepted

WizNet W5100 not connecting to modern switches and routers

I think your problem is due to the MAC address that is being loading into the W5100. Try setting the 2 low order bits of the first byte to 0. These bits define whether the MAC address is unicast or ...
RFG's user avatar
  • 86
5 votes
Accepted

Is the arduino hackable when using communication shields?

You should be pretty safe, at least as long as your code handles the incoming data properly. When you upload a new sketch through USB, the USB-to-serial interface uses the Arduino pins TX0, RX0 and ...
Edgar Bonet's user avatar
  • 43.3k
5 votes
Accepted

if two arduinos are connected by I2C and one of them is using an ethernet shield, does that grant both of them access to the internet?

I2C does not automatically share resources between two connected devices. You would not be able to share an Internet connection from a Mega connected via I2C to another Mega which has an Ethernet ...
jose can u c's user avatar
  • 6,974
5 votes
Accepted

Using c_str() on String for IPAddress with NTPClient provides wrong values

The String object created as return from IPAddress.toString() as parameter to constructor of NtpClient is temporary. It contains the char array returned by c_str(). NTPClient doesn't copy the string, ...
Juraj's user avatar
  • 18k
5 votes
Accepted

Remotely uploading code to an Arduino board over the internet

You can upload to your Arduino board over Ethernet if you flash it with a special bootloader named Ariadne. You will need an Ethernet module or shield that uses the W5100, W5200, or W5500 Ethernet ...
per1234's user avatar
  • 4,178
4 votes

Arduino two Ethernet shields

The ENC28J60 Shields have a Chip-Select-Pin (CS) so you could select between the two shields with this. I'm using the EN28j60 with the Ethercard library and I'm not sure if this could handle two ...
Juergen's user avatar
  • 51
4 votes

MQTT client on Arduino + SIM900

MQTT Library for SIM800 GSM Modem is available at ElementzTechBlog, ElementzGithubRepository Functionalities: Auto connect Automatically connect to TCP and to MQTT server. connect function This ...
Dhanish_Elementz's user avatar
3 votes

Can a 9V battery be used as a backup power supply (to Arduino Uno) while plugged directly into Vin and ground?

No, when you have 9V hooked up to Vin and 5V coming in from the USB, it will use power from the 9V battery, not usb and the battery will quickly be depleted.
mwwalk's user avatar
  • 446
3 votes

Can a 9V battery be used as a backup power supply (to Arduino Uno) while plugged directly into Vin and ground?

My problem with that is that the other side of the diode on the Arduino is normally powered up. So for example if you have a 12V supply in the power jack you'll have 11.3V at Vin (because of the diode ...
Nick Gammon's user avatar
  • 38.4k
3 votes

Disconnect Ethernet Shield

You have correctly determined the root of the problem, both shields are trying to use the same pins. To work around this we need to know which pins are being used, and for what. The Ethernet Shield ...
djbeadle's user avatar
3 votes
Accepted

How to send information from a web-site to the arduino?

Yes of course! First things first - Yes, it is possible to accomplish what you're thinking. The idea is to create a server on the Ethernet Shield and open the webpage hosted by it on any device and ...
Manav's user avatar
  • 426
3 votes
Accepted

How to connect arduino with local network

To connect to a network you need a network interface. This could be an Ethernet interface, a Wifi interface or something that supports TCP/IP. The easiest way of doing this is with ether an Ethernet ...
Code Gorilla's user avatar
  • 5,637
3 votes

My Arduino Ethernet shield is not working

If your Arduino can not get an IP address, it could be because there is a problem with your code, your shield or your network. There doesn't seem to be a problem with your code from a quick glance, ...
Code Gorilla's user avatar
  • 5,637
3 votes

is there a timeout for Ethernet.begin?

The default timeout is 1 minute for DHCP. There is also a response timeout, and in the library millis is used for timeouts. I don't know if there is a timeout for everything, but I suppose there is. ...
Jot's user avatar
  • 3,246
3 votes
Accepted

Arduino Ethernet Shield 2: How can I automatically determine the MAC Address?

No, the W5500 chip does not have a mac address. You can give it any mac address that you want. The router might not like some mac addresses though. There are online mac address generators. The ...
Jot's user avatar
  • 3,246
3 votes

Multiple SPI device

Some card reaaders (as well as display boards with built-in sd socket) use 10-kOhm resistors in series to the CS, DIN and CLK lines, to perform a cheap 5V to 3.3V level translation. This is really not ...
next-hack's user avatar
  • 401
3 votes
Accepted

Is there an Arduino library that uses ARP to get list of connected devices on network?

ARP isn't generally used the way you described. Per the spec, to resolve an IP address into a MAC address, you broadcast an ARP request for the IP address, and receive a unicast response from the ...
romkey's user avatar
  • 1,554
3 votes

2 SPI devices conflict

I had the same problem with my SD card module. I don't have too much knowledge about all details, but it is related that most SD card modules (the simple ones) do not have tri-state functionality, ...
Michel Keijzers's user avatar
3 votes

Leading Zeroes on Arduino Ethernet MAC Address

Writing this in case someone in the future might be interested. The values passed in the Ethernet library is correct. The last value, 0x01 must be 1 and is written correctly, 0x01 in the registers of ...
noobiejp's user avatar
  • 115
3 votes

How to make an arduino webserver over USB? without ethernet shield nor wifi chip

You cannot change what the Arduino's USB does. The USB is not provided by the ATMega2560, but by the USB to UART interface chip. On a genuine Arduino that may be an ATMega16U2 which could be ...
Majenko's user avatar
  • 105k
3 votes

Simple GET request is failing silently

I made it by using EthernetENC library, as suggested by @Juraj. To install the library, simply use the library manager and search for EthernetENC. For those in need, below is a working code #include &...
user2959923's user avatar
3 votes

Arduino shield stacking issue

Both those boards use pin 10 for chip select by default. You will need to change that. Probably the simplest one to change is the LoRa board. If you look at the WiKi page you link to it lists a set of ...
Majenko's user avatar
  • 105k
3 votes

Arduino does not connect to MQTT local broker

The issue was coming from mosquitto local broker, which was being blocked by windows 10 firewall. When I executed mosquitto with the correct permissions on its folder (read and write for "all ...
bardulia's user avatar
  • 141
2 votes

Is an Arduino capable of running 24/7?

Is an Arduino capable of running 24/7? This is a reliability question. In reliability, there are a lots of things to consider. The software. There are more robust softwares. There are less robust ...
next-hack's user avatar
  • 401
2 votes
Accepted

Where can I find a better pinout diagram for "Arduino Ethernet" board?

That's a better one from : https://pinoutguide.com/images/arduino/ethernet.png This one also presents the Arduino Ethernet R3 board and has the extra I2C pins (SCK=A5,SDA=A4) next to the AREF pin.
skourkos's user avatar
2 votes
Accepted

Wired IoT sensor network with PoE?

I think I am using a setup like you wish at my home: PoE Switch (for example Cisco SG300-28P) Arduino Ethernet's with PoE Module (https://www.arduino.cc/en/Main/ArduinoBoardEthernet) I bought one ...
PowerStat's user avatar
  • 190
2 votes

Arduino-like ethernet only board?

Yes, there's the Arduino Ethernet. Available from Sparkfun for example
jogco's user avatar
  • 273
2 votes

Can't connect to my Arduino via W5100 Ethernet shield

"...Please any help? Do I have to assume that my shield is faulty?..." Before trashing the shield, I'd run through a sligtly more comprehensive troubleshooting approach, from the lowest level of the ...
Damiano Verzulli's user avatar
2 votes

W5100 Ethernet Shield to Custom Board Problem

A bit late to the party but... it may be that you are using pins 1, 2, 3 and 4 instead of 1, 2, 3 and 6 on the RJ45. It is unclear whether you are connecting via a header, in which case you my ...
Ian B's user avatar
  • 21

Only top scored, non community-wiki answers of a minimum length are eligible