Skip to main content

Lego Mindstorms – Sentry Robots


Sameer Kumar Shrestha, Northampton

The report presents the dissertation on title Prototype of Sentry Robots for Advanced Security which includes the use of LEGO robots showing interaction between each other with the help of wireless communication medium in Bluetooth. The purpose of the work is to build a communication between multiple LEGO robots using the wireless technology. For this task, the NXT version of LEGO Mindstorms has been selected. It is because there is need of complex communication which is possible through wireless medium such as Bluetooth and also a suitable processing device for the proposed task which is present in the LEGO Mindstorms NXT. The report has also focused on the background information about the NXT system and its great flexibility with LeJOS NXJ as the programming platform. The outcome is the implementation of developed work with the use LEGO Mindstorms NXT and the LeJOS NXJ as programming platform. The task was approached with one LEGO NXT robot maintaining the distance between the object in the environment and searching the object by rotating in case of lost. After the completion of the first task, the next task was to study the communication behavior of multiple robots communicating with each other to fulfill the same job. For this, three NXT robots were taken and programmed in such a way that they form the shape of triangle and keep tracking the object.  All three of them send and wait for the information from each other and process this information to produce a suitable output, i.e. to respond to the action from each other. Thus, it was found that the implementation of several processes to multiple LEGO based communication had faults, due to the technical hitches with the communication technology and limitations of the NXT systems.





All opinions in this blog are the Author's and should not in any way be seen as reflecting the views of any organisation the Author has any association with.

Popular posts from this blog

Micro:bit, Servo control with Micropython or blocks

You can control servos (small ones) from a Micro:Bit directly. Following a link from the David Whale (Twitter ) , thank you, took me to a Kitronik blog post, https://www.kitronik.co.uk/blog/using-bbc-microbit-control-servo/, which has the answer.

The code uses Microsoft Blocks taken from the post, runs the servos 180 degrees and back again, when button A is pressed. It does exactly what it should. I am also using the Tower Pro SG90 servo.
Can it be replicated in Micropython? This is a new mini project, there seems to be little out there yet on how do this but the best so far is this video by PHILG2864:



The closest I have is the following, it is essentially there.
from microbit import *
pin0.set_analog_period(20)
while True:
    pin0.write_analog(180)
    sleep(1000)
    pin0.write_analog(1)
    sleep(1000)

Setting the time period to 20ms  pin0.set_analog_period(20)seems by experiment (and used in the video above) to be best value so far. The reason for pin0.write_analog(1)  set to 1 i…

4Tronix Bit:Bot Neuron Controlled Edge follower

In thelast post I was playing with 4Tronix'sBit:Bot. In this post I will show the initial experimentation with an artificial neuron controlling the Bit:Bot to follow the edge of a line (it follows the left-hand side of the line).


The neurons (well two separate ones, S1 and S2) are produced using weighted sums - summing the weights x inputs [ right-hand sensor (rs) and left-hand sensor (ls)] plus a bias for each neuron in this case w[0] and w[3].







    net=w[0]+w[1]*rs+w[2]*ls           net2=w[3]+w[4]*rs+w[5]*ls

  If weighted sum >=0 then its output 1 otherwise 0 if net>=0:          s1=1     else:         s1=0
    if net2>=0:         s2=1     else:         s2=0
What actual causes S1 to be either 1 or 0 is all defined by a set of weights w (three for the first neurone, S1,  three for S2).
w=[0,-1,1,-1,1,-1]


Converting the outputs of the two neurones S1 and S2 into actions is shown below.

my robot BETT2017

I will start with a confession, I only had about 2 1/2 hours at BETT 2017 due to external time pressures so to say I didn't yet a chance for a good (or even a bad) look around is an understatement; so I am not reviewing the show just a few notes on what I did manage to see.


STEAM Village
First and mostly, it was great to talk to so many people, only few I had met face to face previously, about robots, micro:bits, Raspberry Pis and coding. Most of this happen in the relatively small (compared to the event space) STEAM village and nearby stalls. It was great to see the strong presence of both Raspberry Pi and Micro:Bit Foundation, along the variety of different activities and example usage of both, with Code Club (I know it is part of Raspberry Pi Foundation) there was well. This was all alongside some other companies

Four of these stuck in my mind.

1. DFRobot (https://www.dfrobot.com/) with their range of Arduino-based robots and non-programmable kits. The two kits that caught my eye w…