I want to build a home automation system by hooking up various sensors (e.g., passive IR motion sensors, magnetic door contact switches, etc.) around the house to detect things then send the sensor signals to a central command center / control station.

PIR Motion Sensor

I want to do this wirelessly and solderlessly with a budget of roughly $10 per sensor. So, for example, I could hook up a breadboard circuit that receives the sensor signal and sends it to a Wifi network.

Is there a simple circuit component or IC that can convert the analog sensor signal to a wireless signal and transmit it to the network via wifi without, say, hooking up an entire microprocessor (e.g., Raspberry Pi) to each sensor? A Raspberry Pi for each sensor would blow my budget.

I'm looking to install a simple component part in, say, a solderless breadboard circuit at the sensor level. Then read all the signals off the network at the control panel using a Raspberry Pi or laptop.

What kind of components and configuration would anyone here recommend?

Edit

Apparently, a USB wireless adapter or a network adapter might be the component I'm looking for. But would it be possible to build up a separate breadboard circuit for each sensor and pipe all the signals to the network? If so, how? I want to keep my budget to about $10 per sensor.

USB Wireless Adaptor