scratchClient ist Software, die einen Zugriff von scratch zur Hardware ermöglicht. Auf dem RaspberryPi ist das Ansteuern der GPIO möglich, Lesen von Analogwerten über SPI, aber auch Sprachausgabe oder Netzwerkkommunikation.

Download und Dokumentation hier.

The architecture of the scratchClient is centered around adapters. Broadcasts and variables from scratch are routed to adapters; adapters can send broadcasts/variables.
Which broadcasts/variables are routed is defined by configuration only and is very flexible. There is a mapping layer which converts scratch names to adapter method names.
The scratchClient is a framework, which communicates with scratch, reads configurations and brings adapters in action. A web interface complements for monitoring.
Adapters are small classes with a well defined interface towards the framework. Adapters can control one GPIO line, an ADC, Stepper or alike, but what the do with broadcasts is very flexible. I have build a text to speech interface, for example.
Not to forget: there can be multiple adapters active in one setup (4 buttons, two adc, one pwm or whatever is needed).
And as adapters have no ‘knowledge’ on other adapters, implementing new ones has almost no side effects to the system.

scratch Art Project

Having some spare time in the scratch course at school, we did a short ‘computer art project’. A short introduction to the topic was presented, some materials taken from the following web pages:–– Reichardt_Jasia_ed_Cybernetic_Serendipidity_The_Computer_and_the_Arts.pdf– The task for the kids, 7th class, was to use simple geometrical patterns combined with some randomness. Using […]

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Snap! integration with scratchClient

Some work was performed to integrate Snap! with scratchClient. Here a preview of current results. Snap! is a viable alternative to scratch. Scratch 1.4 on raspberry pi is quite fast, but latest implementation is buggy. Full screen display for example is no longer working. Scratch 2 was based on flash and is not recommended; scratch […]

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scratch 1.4 mesh network with scratchClient

Scratch 1.4 on raspberry pi allows to connect with other scratch instances on other computers. This is an experimental feature. This feature is not available in scratch1.4 for linux or windows, not in scratch2. With this feature multiple scratch 1.4 can share events and (global) variables. As this feature is experimental, there are some constraints […]

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howto: Edit scratchClient Config Files

There was a question on how to edit scratchClient config files. There was the need to add a Button to a GPIO. Button inputs are handled by a GPIOEventInput-Adapter. This short walkthrough will not explain all the details but will concentrate on where to find the files use an editor copy / paste an adapter […]

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scratch2 connected to scratchClient

Did you ever want to control GPIO from scratch2 ? Or other sensors connected to a raspberry pi ? The last days I worked on connecting scratch2 with GPIO on raspberry and more. To be precise, this is done by either using scratchx or since june 2017 with the standalone version of scratch2 for raspbian. […]

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Sonic Pi controlled from scratch

Sonic Pi is great software to produce sounds and to program melodies. Sonic Pi has an API which allows to use some of the program statements from an external program. There are some places in the web where this feature is used with erlang- or ruby-code. This adapter for scratchClient and the programming in scratch  […]

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scratchClient and scroll_phat_hd

There is a nice little led matrix moard from PIMORONI, “SCROLL PHAT HD”. The form factor is for the pi zero, but it runs well also with a pi 3. scratchClient offers support for this board. The interface allows to set pixel with brightness, write large and somewhat smaller text and of course clear the […]

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scratchClient with MQTT-Adapter

MQTT Description MQTT, Message Queue Telemetry Transport, is a is an ISO standard for a publish-subscribe based messaging protocol. It is based on TCP/IP (the ‘usual’ network protocol) and especially designed for small devices and low network bandwidth. A typical infrastructure contains at least one MQTT-Broker and one to many clients connected to the broker. […]

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scratchClient singleton reworked

scratchClient needs to run alone, as a ‘singleton’, on one computer. The reason is that concurrent access to GPIO, SPI or other resources could result in unpredictable results. First approach was to use a pid-file with some logic. At startup, scratchClient writes its own process identification ‘pid’ into a file When another scratchClient is […]

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pi and more 9, workshop ‘raspberry, scratch, gpio’

For the ‘pi and more 9‘ in Trier on 11 june 2016, I had the chance to run a workshop on how to use scratch with gpioserver and as an alternative to use scratch with scratchClient. Basis setup was to control three LED with a button. The introduction is available as a pdf-document. The tutorials […]

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