Blog

PiCockpit showing CPU usage & temperature

The CPU information is updated live in your webinterface. No matter where your Pi will be in the world, if it has an Internet connection and can talk to the PiCockpit MQTT Broker, you will be able to monitor it.CPU Loaded with two hogs:The 51 % refers to overall system load – that is, if [...]

By | August 12th, 2019|PiCockpit|Kommentare deaktiviert für PiCockpit showing CPU usage & temperature

PiCockpit: online / offline states, and MQTT

In the upcoming PiCockpit release, we will have an online status tracking for Pi’s connected via picockpit-client. The online function is realized by MQTT’s Last Will & Testament feature. You can test it by unplugging your Pi from the network. I unplugged the Pi at: 17:59:10At about 18:00:05 it was shown as offline:Why is that? [...]

By | August 8th, 2019|PiCockpit|Kommentare deaktiviert für PiCockpit: online / offline states, and MQTT

VerneMQ how to disconnect clients forceably per command line

There is a commandvmq-admin session showwhich will show you the currently connected clients:Unfortunately, this output is truncated for a total width of 80 characters (no matter how many would fit) and there is currently no indication that it is.See this VerneMQ Github issue: https://github.com/vernemq/vernemq/issues/1200To disconnect clients you need the client_id and the mountpoint. Therefore, you [...]

By | August 8th, 2019|VerneMQ|Kommentare deaktiviert für VerneMQ how to disconnect clients forceably per command line

Paho failure to subscribe

ProblemAMQJS0005E Internal error. Error Message: Cannot read property 'show' of undefinedThis error is shown sporadically, especially when you Shift-Reload the whole page. SolutionI have a Vue.js Plugin to show “toast” messages (Vue.toasted). I currently use it for debugging purposes. Everything worked fine initially, as my code was executed after Vue was initialized and the whole [...]

By | August 8th, 2019|Development, Vue.js|Kommentare deaktiviert für Paho failure to subscribe

First message from picockpit client rendered!

Today, 7.8.2019, at around 18:16 the code is in place for the first message to have been rendered: Thus the Pi “Alexander” is shown as online. Thanks to the magic of vue.js, MQTT, VerneMQ, AdminLTE, Crystal Lang, Python, Paho, AXIOS and much much more!This is the effort of around 320 hours of work (total time invested [...]

By | August 7th, 2019|PiCockpit|Kommentare deaktiviert für First message from picockpit client rendered!

Getting POST requests to work with Axios, Kemal (crystal lang), vue.js

In picockpit.com, I am using AJAX requests to communicate with the backend for update operations. For instance,if you want to change the name of this Pi, you would select:which shows an inline form:how to show this inline form with vue.js is besides the point of this post (even though very interesting!)Clicking on Cancel will cancel [...]

By | August 6th, 2019|Crystal Language, Vue.js|Kommentare deaktiviert für Getting POST requests to work with Axios, Kemal (crystal lang), vue.js

VerneMQ MQTT connection lost (8): AMQJS0008I Socket closed. different mountpoints

In my setup, I am rewriting the mountpoints of clients from the ones set up by the listeners to individual mountpoints depending on client group.The idea behind this is perfect isolation of multi-tenancy on the server. Individual clients from different groups thus are not able to see each other, even when subscribing to “#” (everything). [...]

By | Juli 28th, 2019|VerneMQ|Kommentare deaktiviert für VerneMQ MQTT connection lost (8): AMQJS0008I Socket closed. different mountpoints

Shopify & Langify modify checkout link

Shopify checkout is multilingualThe shopify checkout is multilingual:The trick is to have a &locale=en or &locale=en at the end of the link:You can therefore create buttons, etc. which take your user to the checkout, under the links ofhttps://buyzero.de/checkout?locale=dehttps://buyzero.de/checkout?locale=enwhich will set the locale to the appropriate language.(replace buyzero.de by your domain).Shopify LiquidLiquid is the Shopify template [...]

By | Juli 21st, 2019|Development|Kommentare deaktiviert für Shopify & Langify modify checkout link

Booting Alpine Linux on the Raspberry Pi Compute Module

In our project for a client we are using the Raspberry Pi Compute Module, along with a custom compute module carrier board (called the PCCB – Pi Control Carrier Board) which provides RS485, CAN, RS232, LAN, USB and a step-down for input voltages of 6 – 24 V. (If you are interested in customized hardware [...]

By | Juli 7th, 2019|Alpine Linux, Raspberry Pi Embedded Development|Kommentare deaktiviert für Booting Alpine Linux on the Raspberry Pi Compute Module

Debugging File upload / multipart upload and other HTTP requests

Sometimes you want to see the request as it is received by the server, without any handling / obscuring of the original request.For instance, to see whether different browsers handle file uploads differently. On the other hand, you do not want to write up your own mockup server, just to handle these requests, or install [...]

By | Juli 1st, 2019|Development|Kommentare deaktiviert für Debugging File upload / multipart upload and other HTTP requests