Follow me 4WRD

Lynxmotion Rovers, Sumo, and Tracked
1

Hi Everybody,
I’ve made a lot of search on the net but i didn’t find any kit for a follow me robot.
So what i want to do is to buy the Lnyxmotion autonomous model.
I want to setup a utlrasonic sensor on the front and calculate the distance between this sensor and a remote control.

I have few questions i hope you guys as specialist can help me.

If i setup 1,2 or 3 sensor can i send a ultrasonic sound from an other ultrasonic sensor and calculate the distance.
For exemple the sensor on the robot will try to listen let say 40Mhz and the remote control will send the 40Mhz signal.

I’m a little bit suprised because nobody seems to done it before, so it’s probably so complicated.
Thanks for kind support.

2

40MHz? That’s a little high.

It would be hard to “sync” an external xmtr to an on-board sonar.

You can simply “range” to the “target” you are following, and by mounting your sensors slightly outward to the centerline of the 'bot, get some directionality out the the range reports. Calculate a course from that.

Alan KM6VV

3

Hi Alan,
It was my first idea but if somebody cross between me and the robot, the robot will follow me instead of me.
It’s why i had the idea of creating a kind of link between the robot and me with the ultrasonic sensor.

4

There are some IR beacon and receiver pairs that can give direction (and range?). Try Pololu.

I’ve wanted to play with them, but hadn’t gotten around to ordering them.

Alan
P.S. 20-40KHz is a typical sonar frequency.

5

Another place might be to check out Spark Fun Electronics they carry transmitter receiver pairs, possibly you could guide your bot by signal strenth.

6

Look for an RSSI signal for signal strength.

Alan KM6VV

7

Montaigne,

Check out this link: norrislabs.com/Projects/Foll … index.html

The project uses the original Lynxmotion 4WRD and a Devantech TPA81 thermal sensor (~$100 US).

I built one of these projects except that I used a BS2p to decode the thermal sensor output instead of the PIC used in the project.

Worked fine for me.

Regards,
TCIII

8

I think Montaigne is looking for a more personal locator/beacon , as in the robot only follows him and nothing else that is why a radio beacon of some type for the bot to follow would work. Thermal sensors will detect the heat from every heat source so two people or more could be giving the same heat signature and again the bot would not follow just you.

9

In order to do what he wants I would think he’s going to need multiple sensors working together. An RF signal is fine, but that with the thermal sensor would be useful to know it’s following a human with an RF source. :wink:

10

I agree, the more sensor input the better, I’m interested in this subject due to the fact that I’m slowly building a robot using an electric wheel chair for the base, the base is unaltered and I’m basically interfacing at the hand controller, the purpose is to have a bot/wheelchair robot that can follow a caregiver and also at the same time not run into things.
It sounds easy but getting the bot to follow without ping ponging from wall to wall is not an easy task, multiple sensor input of various kinds and a good hardware/software combination is the ticket.