PurpleDrop Software

This holds the control software for PurpleDrop, a digital microfluidic device. The hardware can be found here.

Overview

This software provides a driver and HTTP gateway for controlling a PurpleDrop DMF device. It supports the PurpleDrop rev6 and later -- i.e. a USB-based hardware design.

The pdserver executable provides a service which detects and connects to a PurpleDrop USB device, and provides access to it through the following endpoints:

1. A JSON-RPC interface is provided at http://0.0.0.0:7000/rpc. See http://0.0.0.0:7000/rpc/map for a list of RPC functions available.
2. A websocket streaming events (protobuf messages defined in protobuf/messages.proto) on ws://0.0.0.0:7001.
3. A javascript front-end at http://0.0.0.0:7000/.

The pdcli executable provides a command line interface for accessing the purpledrop. For example pdcli info will attempt to connect to the device and read its software version. See pdcli --help for full set of commands.

The pdrecord executable can be used to record the eventstream during experiments for later analysis or playback. Example: pdrecord --host ws://192.168.0.2:7001 experiment1.pdlog.

Installing

Clone the repository, and run pip install ..

Documentation

Documentation for this project is compiled using sphinx, lives in the docs directory, and is hosted at https://purpledrop-driver.readthedocs.io.

Rebuilding protobuf messages

purpledrop/protobuf/messages_pb2.py is auto-generated from protobuf/messages.proto. If the message definitions are changed, it needs to be updated manually by running: protoc --python_out=purpledrop protobuf/messages.proto

Javascript front-end

The jsclient directory contains a webpack project which provides a user interface for controlling a purpledrop. After running pdserver, point your browser at localhost:7000 to load.

Deployment

The javascript is bundled into a tarball and deployed with the python package as package data (purpledrop/frontend-dist.tar.gz). The tarball is under source control so that the python project can be installed without working node tools. To rebuild the node project and update the tarball, run make jsclient.

The jsclient project also supports a development server. For more information, see jsclient/README.md.