You have all this C# coding knowledge and you want build hardware gadgets. Try Netduino, which is basically a powerful Arduino running .Net!

An open-source electronics platform using the .NET Micro Framework

Processor: 168MHz Cortex-M4 MCU; 2MB dual-bank flash; 256KB RAM.
Standard I/O: 22 GPIOs combined with SPI, I2C, 4 UARTs (1 RTS/CTS), 6 PWM channels and 6 12-bit ADC channels.
Advanced I/O: 802.11b/g/n (Wi-Fi) with SSL/TLS. MicroSD storage. 3 GoBus 2.0 ports for plug-and-play components.
MicroUSB cable and GoBus cable included. Design files and source code are included.
.NET Micro Framework combines the ease of high-level coding and the raw features of microcontrollers.

Price: $69.95

built a Windows Phone-controlled car with a Netduino and 3D-printed parts.

The Netduino and other .NET Micro boards don’t seem to get much love, but that doesn’t mean they’re not able to use one of the coolest chips we’ve seen in a while. [Valkyrie] has written a driver for TI’s new CC3000 all-in-one WiFi chip, giving any .NET micro device a very small and very cheap WiFi connection.

A while back, [Chris Magagna] created a TI CC3000 library for the Arduino. [Valkyrie] fell out of his chair when he saw that post, as it meant the .NET Micro devices such as the Netduino could finally use this device.

[Christian] is growing a tomato plant on his desk and wanted to capture some time-lapse images of its progress. To that end he built a rig that monitors moisture levels and snaps images at regular intervals.

The hardware he’s using is part of the Gadgeteer family. These run a .NET micro framework and are modular which makes for easy assembly.

The images and moisture readings are all pushed to a server. There is an Ethernet board near the base of the rig. It uses POST to send the image, which is saved by a server-side script. The moisture data is sent via a GET command.

Tomato: what is this?
http://tomatos.have.no.32leav.es/

Hardware
The whole thing is powered by Microsoft .NET gadgeteer. A FEZ Spider mainboard is attached to the back of the rig and connected to all other components using the Gadgeteer-typical ribbon cables. On the top panel, four multi-color LEDs surround the camera. At the bottom of the rig, the USB client module – for power and the ethernet model, share the same mounting hole. The irrigation sensor is not shown in the CAD drawing, but can be seen in the photo. It has not attachment to the rig and is directly placed in the soil of the plant.

Software
The software on running on the Gadgeteer hardware will take a photo and sensor reading every ten minutes. This data is then uploaded to a server via HTTP. On the server side is a simple PHP script, that takes the raw POST data – which is the BMP image of the camera – and saves it in a file. The sensor reading is transmitted as GET parameter and stored in a seperate file alongside the image.

how can I build my own?
You’ll need two things to build one of these: the Gadgeteer modules and access to a laser-cutter.