Connects the Adafruit 16-channel PWM/Servo Shield (PCA9685) to the Raspberry Pi via i2c.
Demonstrates the use of mono & c# to control a servo, stepper and 9V DC motor from the Raspberry Pi.
The project uses:
- PCA9685 16-channel, 12-bit PWM Fm+ I2C-bus LED controller (IC used in the Adafruit 16-channel PWM/Servo Shield)
- Raspberry Sharp IO for i2c comms
- SN754410 quadruple half-H driver for bidirectional DC motor control
- 28BJY-48 5V stepper
- ULN2003A darlington array IC to drive the stepper
A lego ping pong launcher was constructed to showcase the motors in action.
The Visual Studio solution expects raspberry-sharp-io to be cloned into a sibling directory.
ie:
+ +--RPi.Demo +--raspberry-sharp-io
The code intially targeted Mono 2.x with a WinForms UI to allow interactive control of the motors (WinForms running in X-Windows). It now targets mono 3.x which was compiled on the pi so as to take advantage of hard float and enable the use of async/await. WinForms on mono 3.x is broken at the time of writing so a web based UI was required.
SignalR is demonstrated in two ways
- Client-Server-Client topology (eg: pi-IIS-iPhone)
SignalR hub is hosted on IIS 8 with two hubs: one hub for a web browser remote control client using jQuery mobile; a second hub for the pi itself to connect to via the signalR c# client. This works well, apart from the requirement of IIS 8 as the mediator. see:
rpi.console/rpiconsole.exe -m=SignalRTest
- Self contained/hosted console app, using Nancy, SignalR and NoWin.
SignalR on mono cannot host websockets and the transport falls back to Server Side Events. Response is very slow while dragging a slider backward and foward with several seconds lag before the server sees this response. Response is even slower using Katana as the web server. see:
rpi.nancy/rpi-nancy.exe
A video of it all working is on youtube.