Wireless Temperature Sensor Rev 1.0

Posted on Posted in Electronics, Projects

Well in the past I had talked about wanting to do a big home automation project and to start with that I wanted to design a battery powered wireless sensor node that I could place around my apartment. The first iteration of this design was posted here http://andrewswanton.com/?p=780 but I had problems with the PIC24 microcontroller I designed in to that one.

I have been wanting to get some experience programming Atmel AVRs since they seem to be very popular and look like very nice little 8-bit microcontrollers. I took the same basic design of the last revision and replaced the microcontroller with the Atmel ATmega168. Since these are very popular microcontrollers so I figured there would be a lot of libraries already done to me getting it up and running quicker. Although, this microcontroller doesn’t have all the fancy low power features of the low power series PIC24 used in the last version but I figure that I get get the power consumption down by having it sleep most of the time and then just quickly wake up every once and a while to read the temperature sensor and then transmit.

Here is picture of the populated board with the NRF24L01 wireless module.

Sensor Rev 1 Layout

DSC00506

Layout:

DSC00506

 

Schematic:

Wireless Temperature Sensor Rev 1_0

Now I actually designed this a while ago and am just getting around to posting about it now. Since designing this board I have been thinking about the whole system design and am thinking about taking a different approach. Instead of having this local network of sensors that talk to a main “server” in my apartment why not jump on the “Internet of Things” bandwagon that everyone else is doing and make it Wifi enabled. This eliminates having to deign a support the local server portion of the system and I could have the devices talk to some sort of “cloud” service. Anyway it’s just an idea and I will post more about it in the future and if it doesn’t work out I can always come back to this design.

Andrew