Wireless Strength Reading

Good afternoon! So I have a mini school project that I will be working on at the end of this semester. Its for a microcontroller class and we are using the MSP430 Microcontroller. So what I would like to do with the MSP430 is hook up an external component that will be able to read the wireless access points around me and send that that information to the MSP430 where I will be able to program that input and write the code to have several LEDs light up depending on the signal strength. My professor likes the idea but since its a small project he doesn’t want me to take on more then I should for this and he was worried about analog conversions. So would anyone be able to point me in the right direction in finding this component that I can attach to my MSP430? Thank you in advance.

Any wifi module with a serial output can be attached to a micro, and will report RSSI from a given access point (WiFly, ESP8266, etc.).

Keep in mind that RSSI depends very strongly on the relative orientation of the receiving and transmitting antennas, so unless you are careful with orientation, the measurements will be meaningless.

Thank you for the reply. Just out of curiosity do you recommend any wifi module in particular? (Previous experience or heard good things about).

As a follow up, you mentioned orientation, the AP (at my university) should be omni-directional, wouldn’t the wifi module also be (or wouldn’t it be the most common?). Also that RSSI report, will it be reported in a digital manor over an analog. Cause the issue my professor was worried about is the wifi module giving analog information and then we would have to do conversion for digital to have it work with MSP430 microcontroller.

Little more information. The building that I would be using for testing (and for my senior project, which is a different class then this assignment and different microcontroller involved) is squared shaped with classrooms on both sides of the squares and this pattern is repeated for 5 floors. For this, I will be based out of the first floor where from what i’ve noticed the AP are going around the square in the hallway (visible on the ceiling).

Hopefully this information is useful, if not, there is no need to really dig into this, like I mention, our professor wants a basic project so if it becomes to complex he would prefer us to change our ideas to something we can complete in a week.

This course could be considered more of an intro to microcontrollers, thus why i keep mentioning the simplicity of it. On top of that i’m currently take analog electronics concurrently, so since we are at the beginning of the semester I probably wouldn’t know how to do proper analog to digital conversions.

All antennas have an orientation for maximal signal strength, which you can verify by experiment. Wifi access point antennas are usually vertical dipoles, but many can be adjusted to be horizontal or any orientation in between. Omnidirectional is not the issue.

All information sent by wifi is digital, or presented by the wifi module over the serial port, is digital.

I’ve used the Roving Networks WiFly module, but the ESP8266 is very cheap and popular. You do not need a microprocessor to experiment with either of them. Just use a 3.3V USB-TTL serial converter to interface with any computer, running a serial port terminal program.

Sorry for the late reply. I wanted to wait to speak to my professor. Seems like the information you have provided was the info he needed. The only other thing he was worried about was the speed (I believe he said our MSP430 wasn’t that fast), but he said its something i’ll need to worry about. Thank you for the information.

SmoKeSoul:
Good afternoon! So I have a mini school project that I will be working on at the end of this semester. Its for a microcontroller class and we are using the MSP430 Microcontroller. So what I would like to do with the MSP430 is hook up an external component that will be able to read the wireless access points around me and send that that information to the MSP430 where I will be able to program that input and write the code to have several LEDs light up depending on the signal strength. My professor likes the idea but since its a small project he doesn’t want me to take on more then I should for this and he was worried about analog conversions. So would anyone be able to point me in the right direction in finding this component that I can attach to my MSP430? Thank you in advance.

Tell prof we pro's say he should move into this century with a small ARM M0 or M3 microprocessor!

The ESP8266 + an MCU can read/report RSSI (signal strength) of 802.11 SSIDs.

You do the assignment on how to use existing code to do so… and convert that number to a displayable form, like a bar graph LED set.

Better yet

https://store.particle.io/ (Photon)

Hint: RSSI is measured in dBm (decibels relative to 1 milliwatt). Read up on that. A WiFi signal will be in the range of -10dBm to -80dBm. Any less than -80dBm and the WiFi 802.11 signal is not useful.