Category: Coding

Scratch

A few of the books I got for Anya are introductions to programming — Python, C++, and this GUI block-based system called Scratch. She likes using Python because Scott and I use it, but she absolutely adores Scratch. She has A Beginner’s Guide To Coding (Marc Scott) that I picked up from Book Outlet (I get a bonus 10$ when someone uses my referral link) for a couple of bucks. We’ve got a studio of our games online, and she’s excited to share the games with family members.

Tricks we’ve leaned so far:

  • The UI will not match a book written a few years ago 🙂 This reminded me a bit of the “Internet Directory” book I had in 1994 … an obviously silly concept today, but a completely reasonable thing in 1994 when a decent bit of the content was still modem numbers. A book about a UI … it’s a good base — providing great first projects. But it took Anya a little while to accept that, while the book quite clearly told her to click an icon that looked like this … in the intervening 18-24 months, the UI had changed. How did I know this is what you click now? I mean, other than the fact it goes into the thing that has the same function as the one your book describes? A good guess!
  • You can create variables with the same name. I am certain they are assigned some underlying UID that you never see, but if you have two variables named ‘score’ and the score doesn’t seem to be incrementing … look at your variable list.
  • Variable scope of “this sprite” and “all sprites” is straight-forward until you create clones. “This sprite” means “this clone of a sprite”. We had a “all sprites” variable for speed and all of the clones will change speed each time a new clone pops in. This is cool if it’s what you want to do. I’ve also created variables scoped to “this sprite” to build clones that move at different speeds.
  • You cannot, unfortunately, change a variable’s scope after you create it. You need to make a new one.
  • The “glide” motion isn’t good for sensing collision. While the glide is in progress, that’s the block that is executing. Anya has a game where a crab collects crystals while avoiding divers which uses the fact you cannot check if Thing1 is touching Thing2. The grab can move through gliding divers with impunity. If you want to detect collisions, use a loop where the X and Y coordinates are changed in small increments instead of glide. Technically, there’s no collision detection while my X coordinate is changing, but that’s such a brief time interval that you cannot effectively avoid bumping into the other sprite while it moves.

  • You can avoid the sprite being moved off of the screen to avoid collision by adding a bounce when the sprite is on the edge.

  • You need to zero out your variables when the green flag is pressed, otherwise replaying the game by clicking the green flag again produces really strange behavior (you’ve already won or lost)
  • Fractions can be used in places where they have integer examples. Specifically, you can pause for fractional seconds.
  • When using clones, hide the “base” sprite that exists in the ‘when green flag clicked’ instantiation; use a ‘show’ in the ‘when I start as a clone’ block. Otherwise you have one sprite sitting at the edge of the screen

  • “My Blocks” is used to build functions. In Anya’s Simon Says… game, we use the pseudorandom number generator to select “Simon’s” instructions and call a block based on the generated number.

Filtering HTML Drop-down

I’ve got a few drop-downs that I’ve added filtering on the drop-down – start typing and you’ll see the options that match your string. But I needed to mirror an application functionality where you select a category and are then presented with a list of options that fit the category.

Here’s the drop-down selector for the categories

    echo "      <div class=\"row\">\n";
    echo "          <div class=\"col-md-12 col-sm-12 col-lg-12 col-xs-12\">\n";
    echo "              <div class=\"row\">\n";
    echo "                  <div class=\"row\">\n";
    echo "                      <div class=\"col-md-2 col-sm-2 col-lg-2 col-xs-2 text-left\">\n";
    echo "                          <span><strong>Animal Category:</strong></span>\n";
    echo "                      </div>\n";
    echo "                      <div class=\"col-md-10 col-sm-10 col-lg-10 col-xs-10 text-left form-group\">\n";
    echo "                          <select name=\"strAnimalType\" id=\"strAnimalType\" readonly/> \n";
    echo "                              <option class=\"NoSelection\" value=\"-----\">-----</option>\n";
    echo "                              <option class=\"Feline\" value=\"201\">Feline</option>\n";
    echo "                              <option class=\"Canine\" value=\"202\">Canine</option>\n";
    echo "                              <option class=\"Equine\" value=\"203\">Equine</option>\n";
    echo "                              <option class=\"Other\" value=\"204\">Other</option>\n";
    echo "                          </select>\n";
    echo "                      </div>\n";
    echo "                  </div>\n";

And here’s the drop-down selector I want to filter based on category — there are a lot of options. The class for each option includes the category selectors that will include the option in the drop-down.

    echo "      <div class=\"row\">\n";
    echo "          <div class=\"col-md-12 col-sm-12 col-lg-12 col-xs-12\">\n";
    echo "              <div class=\"row\">\n";
    echo "                  <div class=\"row\">\n";
    echo "                      <div class=\"col-md-2 col-sm-2 col-lg-2 col-xs-2 text-left\">\n";
    echo "                          <span><strong>Pet Breed:</strong></span>\n";
    echo "                      </div>\n";
    echo "                      <div class=\"col-md-10 col-sm-10 col-lg-10 col-xs-10 text-left form-group\">\n";
    echo "                          <select name=\"strPetBreed\" id=\"strPetBreed\" readonly/> \n";
    echo " <option value=\"-----\" class=\"selectors All\">-----</option>\n";
    echo " <option value=\"101\" class=\"selectors Feline\">Domestic Shorthair</option>\n";
    echo " <option value=\"1275\" class=\"selectors Feline\">Flame Point Siamese</option>\n";
    echo " <option value=\"1069\" class=\"selectors Equine\">Arabian</option>\n";
    echo " <option value=\"1071\" class=\"selectors Equine\">Tennessee Walking Horse</option>\n";
    echo " <option value=\"1072\" class=\"selectors Other\">Chicken</option>\n";
    echo " <option value=\"1073\" class=\"selectors Other\">Snake</option>\n";
    echo " <option value=\"1074\" class=\"selectors Canine\">Australian Shepherd</option>\n";
    echo " <option value=\"1075\" class=\"selectors Feline\">Burmese</option>\n";
    echo " <option value=\"1076\" class=\"selectors Canine\">Siberian Husky</option>\n";
    echo " <option value=\"1077\" class=\"selectors Feline\">Sphinx</option>\n";
    echo " <option value=\"1078\" class=\"selectors Other\">Rabbit</option>\n";
    echo "                          </select>\n";
    echo "                      </div>\n";
    echo "                  </div>\n";
    echo "              </div>\n";
    echo "          </div>\n";
    echo "      </div>\n";

In the JavaScript, I’ve got a quick function that repopulates the rather long drop-down menu based on the selected category

// Filter strPetBreed options based on strAnimalCategory value
$(document).ready(function () {    
    var allOptions = $('#strPetBreedoption')
    $('#strAnimalCategory').change(function () {
        $('#strPetBreed option').remove()

        var classN = $('#strAnimalCategory option:selected').prop('class');
        var optsCat = allOptions.filter('.' + classN);
        $.each(optsCat, function (i, j) {
            $(j).appendTo('#strPetBreed');
        });

        var optsAll = allOptions.filter('.All');
        $.each(optsAll, function (i, j) {
            $(j).prependTo('#strPetBreed');
        });

    });
});

Since it’s possible there are options you’d want to always appear (in my case, it’s just the “—–” to indicate no selection has been made … but there could be real items that fall into each category too), I’ve got an “All” classification that will get popped onto the top of the list.

NodeJS Unit File

For future reference, this is an example unit file for running a NodeJS server with systemd. The NodeJS code we use reads from a local MariaDB, so I’ve added a service dependency for the database server.

Create /etc/systemd/system/nodeserver.service

[Unit]
Description=SiteName Node.js Server
Requires=After=mariadb.service

[Service]
ExecStart=/path/to/binary/for/node /path/to/nodeJS/html/server.js
WorkingDirectory=/path/to/nodeJS/html
Restart=always
RestartSec=30
StandardOutput=syslog
StandardError=syslog
SyslogIdentifier=nodejs-sitename
User=web-user
Group=www-group

[Install]
WantedBy=multi-user.target

Use systemctl daemon-reload to register the new unit file, then “systemctl start nodeserver.service” to start the service. Assuming everything works properly, use “systemctl enable nodeserver.service” to have the service start on boot.

LDAP Authentication: Python Flask

This is a quick python script showing how the flask-ldap3-login module can be used to authenticate and gather user attribute values

from flask_ldap3_login import LDAP3LoginManager
from ldap3 import Tls
import ssl

config = dict()

config['LDAP_HOST'] = 'ad.example.com'

# Use SSL unless you are debugging a problem. Clear text port is 389 and tls_ctx needs to be removed from add_server call
config['LDAP_USE_SSL'] = True
config['LDAP_PORT'] = 636

# Base DN
config['LDAP_BASE_DN'] = 'dc=example,dc=com'

# User Base DN, prepended to Base DN
config['LDAP_USER_DN'] = 'ou=UserDN'

# Groups Base DN, prepended to Base DN
config['LDAP_GROUP_DN'] = 'ou=SecurityGroupDN'

# Server will be manually added to establish SSL
config['LDAP_ADD_SERVER'] = False

# Domain component of userprincipal name
config['LDAP_BIND_DIRECT_SUFFIX'] = '@example.com'

# Search scope needs to be subtree
config['LDAP_USER_SEARCH_SCOPE'] = "SUBTREE"

# Attributes to return
config['LDAP_GET_USER_ATTRIBUTES'] = ("mail", "givenName", "sn")

# Setup a LDAP3 Login Manager.
ldap_manager = LDAP3LoginManager()

# Init the mamager with the config since we aren't using an app
ldap_manager.init_config(config)

# TLS settings to establish trust without validating CA issuance chain. 
# Can use CERT_REQUIRED and ca_certs_file with path to cacerts that includes issuing chain
tls_ctx = Tls(
    validate=ssl.CERT_NONE,
    version=ssl.PROTOCOL_TLSv1,
    valid_names=[
        'ad.example.com',
    ]
)

ldap_manager.add_server(
    config.get('LDAP_HOST'),
    config.get('LDAP_PORT'),
    config.get('LDAP_USE_SSL'),
    tls_ctx=tls_ctx
)

# Validate credentials
response = ldap_manager.authenticate_direct_credentials('e0012345', 'P@s5w0rdG03sH3re')
print(response.status)
print(response.user_info)

LDAP Authentication and Authorization: PHP

Blah

<?php
    error_reporting(0);
    #=== FUNCTION ==================================================================
    #      NAME: ldapAuthenticationAndAuthorizationWithAttributes
    #      PARAMETERS:
    #                    $strLDAPHost                   String  LDAP Server URI
    #                    $strUIDAttr                    String  Schema attribute for user ID search
    #                    $strSystemUser                 String  System credential username
    #                    $strSystemPassword             String  System credential password
    #                    $strUserBaseDN                 String  User search LDAP base DN
    #                    $strLogonUserID                String  Input user ID
    #                    $strLogonUserPassword          String  Input user password
    #					 $arrayAttrsToReturn			String	Attributes to be returned
    #                    $strGroupBaseDN                String  (optional) Group search LDAP base DN
    #                    $strGroupNamingAttribute       String  (optional) Schema attribute for group search
    #                    $strMembershipAttr             String  (optional) Schema attribute for group membership
    #                    $strAuthGroup                  String  (optional) Group name
    #     DESCRIPTION: Verify authentication and authorization against AD server.a
    #
    #     RETURNS: array(BindReturnCode, Authorized, array(returnValues))
    #                        BindReturnCode:    -1 indicates LDAP connection failure, -2 indicates system account auth failed, -3 indicates user auth not attempted, >=0 is IANA-registered resultCode values (https://www.iana.org/assignments/ldap-parameters/ldap-parameters.xml#ldap-parameters-6)
    #							NOTE: 0 is successful authentication in IANA-registered resultCode
    #                        Authorized:        0 authorization not attempted, -1 is not a member of the located group, 1 is member of the located group
    #						arrayUserAttributeValues	Array with values of $arrayAttrsToReturn
    #
    #     USAGE: $arrayUserAuthorized = ldapAuthenticationAndAuthorizationWithAttributes("ldaps://ad.example.com","sAMAccountName","ldapquery@example.com", "Sy5t3mP@ssw0rdG03sH3re", "ou=example,dc=example,dc=com", $strInputUserName, $strInputUserPassword, array('givenName', 'sn'), "ou=securitygroups,dc=example,dc=com","cn", "member", "LJRTestGroup")
    #===============================================================================
    function ldapAuthenticationAndAuthorizationWithAttributes($strLDAPHost,$strUIDAttr, $strSystemUser, $strSystemPassword, $strUserBaseDN, $strLogonUserID, $strLogonUserPassword, $arrayAttrsToReturn, $strGroupBaseDN=null, $strGroupNamingAttribute=null, $strMembershipAttr=null, $strAuthGroup=null){
        $arrayAuthResults = array();
        $arrayUserAttributeValues = array();
        // Validate password is not null, otherwise directory servers implementing unauthenticated bind (https://tools.ietf.org/html/rfc4513#section-5.1.2) will return 0 on auth attempts with null password
        if( strlen($strLogonUserPassword) < 1){
            $arrayAuthResults['BindReturnCode'] = -3;
            $arrayAuthResults['Authorized'] = -1;
        }
        else{
            // Connect to the LDAP directory for system ID queries
            $systemDS = ldap_connect($strLDAPHost);
            ldap_set_option($systemDS, LDAP_OPT_PROTOCOL_VERSION, 3);

            if ($systemDS) {
                // Bind with the system ID and find $strLogonUserID FQDN
                $systemBind = ldap_bind($systemDS, $strSystemUser, $strSystemPassword);

                if(ldap_errno($systemDS) == 0){
                    $strLDAPFilter="(&($strUIDAttr=$strLogonUserID))";
                    $result=ldap_search($systemDS,$strUserBaseDN,$strLDAPFilter, $arrayAttrsToReturn);

                    $entry = ldap_first_entry($systemDS, $result);

                    $strFoundUserFQDN= ldap_get_dn($systemDS, $entry);

                    if($strFoundUserFQDN){
                        $userDS = ldap_connect($strLDAPHost);
                        ldap_set_option($userDS, LDAP_OPT_PROTOCOL_VERSION, 3);

                        $userBind = ldap_bind($userDS, $strFoundUserFQDN, $strLogonUserPassword);
                        $arrayAuthResults['BindReturnCode'] = ldap_errno($userDS);

                        ldap_close($userDS);

                        if($arrayAuthResults['BindReturnCode'] == 0){
                        	$objFoundUser = ldap_get_entries($systemDS, $result);
							for($arrayAttrsToReturn as $strAttributeName){
								$arrayUserAttributeValues[$strAttributeName] = $objFoundUser[0][$strAttributeName];

							}
							$arrayAuthResults['AttributeValues'] = $arrayUserAttributeValues;
                            //////////////////////////////////////////////////////////////////////////////////////
                            // If an auth group has been supplied, verify authorization
                            //////////////////////////////////////////////////////////////////////////////////////
                            if($strAuthGroup){
								// Escapes in DN need to be double-escaped or bad search filter error is encountered
                                $strGroupQuery = "(&($strGroupNamingAttribute=$strAuthGroup)($strMembershipAttr=" . str_replace("\\","\\\\", $strFoundUserFQDN) . "))";

                                $groupResult = ldap_search($systemDS,$strGroupBaseDN, $strGroupQuery);
                                $authorisedState = ldap_count_entries($systemDS ,$groupResult);

                                // If a group matching the filter is found, the user is authorised
                                if($authorisedState == 1){
                                    $arrayAuthResults['Authorized'] = 1;
                                }
                                // Otherwise the user is not a member of the group and is not authorised
                                else{
                                    $arrayAuthResults['Authorized'] = -1;
                                }
                            }
                            else{
                                $arrayAuthResults['Authorized'] = 0;
                            }
                            //////////////////////////////////////////////////////////////////////////////////////
                            ldap_close($systemDS);
                        }
                        // If the bind failed, the user has not logged in successfully so they cannot be authorized
                        else{
                            $arrayAuthResults['Authorized'] = -1;

                            ldap_close($systemDS);
                            ldap_close($userDS);
                        }
                    }
                    // User not found in directory
                    else{
                        $arrayAuthResults['BindReturnCode'] = 32;
                        $arrayAuthResults['Authorized'] = -1;
                    }
                }
                // system bind failed
                else{
                    $arrayAuthResults['BindReturnCode'] = -2;
                    $arrayAuthResults['Authorized'] = -1;
                    ldap_close($systemDS);
                }
            }
            // ldap connection failed
            else{
                $arrayAuthResults['BindReturnCode'] = -1;
                $arrayAuthResults['Authorized'] = -1;
            }
        }
        return $arrayAuthResults;
    }

    print "User password not supplied:\n";
    $arrayNullPassword = array();
    $arrayNullPassword = ldapAuthenticationAndAuthorizationWithAttributes("ldaps://ad.example.com","sAMAccountName","ldapquery@example.com", "Sy5t3mP@ssw0rdG03sH3re", "ou=example,dc=example,dc=com", "e0012345", '');
    var_dump($arrayNullPassword);

    print "Bad password:\n";
    $arrayBadPassword = array();
    $arrayBadPassword = ldapAuthenticationAndAuthorizationWithAttributes("ldaps://ad.example.com","sAMAccountName","ldapquery@example.com", "Sy5t3mP@ssw0rdG03sH3re", "ou=example,dc=example,dc=com", "e0012345", 'N0tTh3P@s5w0rd',"ou=SecurityGroups,dc=example,dc=com","cn", "member");
    var_dump($arrayBadPassword);

    print "\nInvalid user:\n";
    $arrayUserNotInDirectory = array();
    $arrayUserNotInDirectory = ldapAuthenticationAndAuthorizationWithAttributes("ldaps://ad.example.com","sAMAccountName","ldapquery@example.com", "Sy5t3mP@ssw0rdG03sH3re", "ou=example,dc=example,dc=com", "xe0012345", 'xDoesN0tM@tt3r');
    var_dump($arrayUserNotInDirectory);

    print "\nGood password without authorization:\n";
    $arrayUserAuthenticated = array();
    $arrayUserAuthenticated = ldapAuthenticationAndAuthorizationWithAttributes("ldaps://ad.example.com","sAMAccountName","ldapquery@example.com", "Sy5t3mP@ssw0rdG03sH3re", "ou=example,dc=example,dc=com", "e0012345", 'Us3rP@s5w0rdG035H3re|Us3rP@s5w0rdG035H3re');
    var_dump($arrayUserAuthenticated);

    print "\nGood password with authorized user:\n";
    $arrayUserAuthorized = array();
    $arrayUserAuthorized = ldapAuthenticationAndAuthorizationWithAttributes("ldaps://ad.example.com","sAMAccountName","ldapquery@example.com", "Sy5t3mP@ssw0rdG03sH3re", "ou=example,dc=example,dc=com", "e0012345", 'Us3rP@s5w0rdG035H3re|Us3rP@s5w0rdG035H3re',"ou=SecurityGroups,dc=example,dc=com","cn", "member", "cfyP_Unix_UnixUsers");
    var_dump($arrayUserAuthorized);

    print "\nGood password with unauthorized user:\n";
    $arrayUserNotAuthorized = array();
    $arrayUserNotAuthorized = ldapAuthenticationAndAuthorizationWithAttributes("ldaps://ad.example.com","sAMAccountName","ldapquery@example.com", "Sy5t3mP@ssw0rdG03sH3re", "ou=example,dc=example,dc=com", "e0012345", 'Us3rP@s5w0rdG035H3re|Us3rP@s5w0rdG035H3re',"ou=SecurityGroups,dc=example,dc=com","cn", "member", "WIN AM Team West");
    var_dump($arrayUserNotAuthorized);

    print "\nBad system account:\n";
    $arrayBadSystemCred = array();
    $arrayBadSystemCred = ldapAuthenticationAndAuthorizationWithAttributes("ldaps://ad.example.com","sAMAccountName","ldapquery@example.com", "xSy5t3mP@ssw0rdG03sH3re", "ou=example,dc=example,dc=com", "e0012345", 'Us3rP@s5w0rdG035H3re|Us3rP@s5w0rdG035H3re');
    var_dump($arrayBadSystemCred);

?>

LDAP Authentication: PHP and Active Directory

This is a very brief function that authenticates a user against Active Directory. Because you can authenticate using a fully qualified DN, sAMAccountName, or userPrincipalName … there’s no need to use a system credential or search for the user provided you’ve got a single domain in your forest (i.e. you know what to prepend to the sAMAccountName or postpend to userPrincipalName).

If you need to perform authorization as well as authentication, you’ll need the user’s FQDN so use the generic LDAP authentication and authorization function.

<?php
    error_reporting(0);
    #=== FUNCTION ==================================================================
    #      NAME: activeDirectoryLDAPAuthentication
    #      PARAMETERS: 
    #                    $strLDAPHost                   String  LDAP Server URI
    #                    $strLogonUserID                String  Input user ID
    #                    $strLogonUserPassword          String  Input user password
    #     DESCRIPTION: Verify authentication againt Active Directory server.
    #     
    #     RETURNS: int BindReturnCode:    -2 indicates LDAP connection failure, -3 indicates user auth not attempted, >=0 is IANA-registered resultCode values (https://www.iana.org/assignments/ldap-parameters/ldap-parameters.xml#ldap-parameters-6)
    #							NOTE: 0 is successful authentication in IANA-registered resultCode
    #
    #     USAGE: $iBindResult = activeDirectoryLDAPAuthentication("ldaps://ad.example.com", $strInputUserName, $strInputUserPassword)
    #===============================================================================
    function activeDirectoryLDAPAuthentication($strLDAPHost, $strLogonUserID, $strLogonUserPassword){
        $iBindReturnCode = null;
        // Validate password is not null, otherwise directory servers implementing unauthenticated bind (https://tools.ietf.org/html/rfc4513#section-5.1.2) will return 0 on auth attempts with null password
        if( strlen($strLogonUserPassword) < 1){
            $iBindReturnCode = -1;
        }
        else{
            $userDS = ldap_connect($strLDAPHost);
            if($userDS){
                ldap_set_option($userDS, LDAP_OPT_PROTOCOL_VERSION, 3);

                $userBind = ldap_bind($userDS, $strLogonUserID . '@example.com', $strLogonUserPassword);
                $iBindReturnCode = ldap_errno($userDS);
                ldap_close($userDS);
            }
            // ldap connection failed
            else{
                $iBindReturnCode = -2;              
            }        
        }
        return $iBindReturnCode;
    }

    $iBadUser = activeDirectoryLDAPAuthentication("ldaps://ad.example.com", "xe0012345", 'N0tTh3P@s5w0rd');
    print "\nInvalid user: $iBadUser\n";

    $iUserAuthenticated = activeDirectoryLDAPAuthentication("ldaps://ad.example.com", "e012345", 'Go0dP@s5w0rdH3r3');
    print "\nGood password: $iUserAuthenticated\n";

    $iBadPassword = activeDirectoryLDAPAuthentication("ldaps://ad.example.com", "e0012345", 'N0tTh3P@s5w0rd');
    print "\nBad password: $iBadPassword\n";

    $iBadHost = activeDirectoryLDAPAuthentication("ldaps://abc.example.com", "e0012345", 'N0tTh3P@s5w0rd');
    print "\nBad host: $iBadHost\n";

?>


Maven Deploy To Github Packages – Error 422: Unprocessable Entity

There is logical consistency to this error, but it would be nice if the error message was a little more indicative of the problem. Scott deployed a JAR to Github Packages. He needed to make a few changes and then was unable to upload the package in his deployment. The error indicted the jar was unable to be transferred to/from Github with error 422. Which was a new one on me — quick search produced the fact 422 is “Unprocessable Entity”. And, yeah, the maven error said exactly that if I’d bothered to read the whole error. I suggested incrementing the version, and the deploy succeeded.

Since GitHub doesn’t allow you to delete public packages, it seems logical that they wouldn’t allow you to overwrite public packages either (if nothing else, I could overwrite it with a text file that says “DELETED” and essentially have deleted the package). Since he was able to deploy the package successfully with a new version tag, it appears that you cannot delete or overwrite public packages. Each new push needs to have a unique tag.

ESP8826 (12e) Multisensor

We’d set up a prototype multi-sensor with an environment sensing kit that Scott picked up at MicroCenter a few years ago. There’s a little LCD display … but we wanted to report readings back to our OpenHAB server. Which required a network connection. Checking out prices for network cards to add to the Uno … well, it wasn’t a cheap add-on. But we found these ESP8266 modules that support 802.11b/g/n and provide the memory/processing for small programs. At about 3$ delivered, that was exactly what we needed.

I ordered a bunch of components to make multi-sensors – pressure sensors, luminescence sensors, temperature/humidity sensors. The sensors connect into a CP2102 ESP8266. The device is powered by a couple of 18650’s in a little box — another buck. There’s some miscellaneous wiring and a little breadboard, too. The total cost for the multi-sensor is about 8.50$. We could add a vibration sensor for another 0.50$, a PIR sensor for 2$, and a UV sensor for 2.50$. That’s 13.50$ for 7 different sensors — and we don’t need seven sensors everywhere.

I kind of want to make a weather station too — add a water level sensor, a precipitation detector, and a wind speed sensor. Those are surprisingly expensive! I want to check out the process to build your own anemometer. But I’d probably buy a nice Davis Anemometer 🙂

Connecting to a WiFi network with the ESP8266 is really easy:

  • Add a library to the Arduino IDE
    • In the Arduino IDE preferences, select File>Preferences menu.
    • In the “Additional Boards Manager URLs” field, add ‘https://arduino.esp8266.com/stable/package_esp8266com_index.json’
    • Select the Tools > Board menu and open the Boards Manager. Search for “esp8266” and install the platform.
    • From the Tools > Board menu, select the appropriate board. I ordered the CP2102 ESP8266 module, and we’re using “NodeMCU 1.0 (ESP-12E Module)” as the board.
  • Configure the WiFi network connection details in your code
  • Compile
  • Upload
  • You’ve on the network!

We’ve used an MQTT library and send sensor readings to our MQTT server.

 

Composer Hangs

I don’t use composer often, and it generally just works … so I don’t know much about it beyond “another package manager”. But every once in a while, it just hangs. Nothing happening, nothing instructive in strace. Fortunately, composer has several levels of verbosity on the output. While the default output is minimal and offers absolutely no clue that it’s doing something … adding -vvv is a nicely verbose output that lets me see that the package install isn’t actually hung. It’s just going to take a long time.