Mission Possible (Engineering an Alarm) #4826


The mirrors would definitely be a challenge for students. If they have the “growth mindset” they will probably succeed. However, many of my students will try for a short while and then give up. Many are not used to the engineering process, the constant trying to solve problems, and just use to textbook type answers.


The mirrors and setup were definitely a challenge. I did it myself and should probably be a team/group activity.


Change it to a light sensor (LED) or maybe some sort of vibration/touch alert. Not sure if they have one, but that would be cool.


That’s interesting to also incorporate lessons on types of lasers and quality! That’s a great tip!


The first part of the engineering challenge was fine. However, the mirror and laser were definitely a challenge for me. I needed more mirrors and a good laser. I just ordered them from Amazon. I will feel comfortable assigning the challenge when I master it.
It will be a great activity to do with Middle schoolers. We’re a boarding school; it will be a great activity for the boarders to monitor who goes into their room.


It was definitely a fun and challenging activity!

I would probably break up the activity into mini-lessons so my 5th grade students can follow along better. The topics of lasers and how we can use mirrors will be an extension the light unit they studies a few months ago. We haven’t discussed lasers in detail, and the hands-on activity will give them some first hand experience as to how they behave versus other light sources. It definitely will also tie in with math and the angle of the mirrors.

Students might require support in understanding how the circuitry functions and works. Another area might be being safe with the lasers, so the laser doesn’t get into anyone’s eyes.

My role would be to explain the overall idea of lasers, mirrors, and the technology. I would then help students with understanding how the mirrors reflect the laser at specific angles.

Students will have independence in improving this project or trying out another use for it. The lesson would be successful if students understood the nature of lasers, and were able to describe how what they created works.


I agree that 3rd and 4th grade students would be able to participate in a way with this activity. We talk about sensors in 3rd grade, and get into more detail with 4th grade. Our 4th graders are interested in robots that could help the environment, and this technology might be something that could spark more ideas from them.


At my school we are trying to figure out how to progress from Little Bits to the next level. I agree that starting with something simpler and then adding more complicated technology as students progress is the way to go.


I really like that this experiment brings together more elements - coding, sound, trig/geometry, lasers, etc. My students are coding majors. The coding parts they’ll get… but they’ve spent little time close to hardware. I like this experiment gets them thinking on how the code and hardware relate.

I’ve noticed challenges with trig & geometry when I have students in astronomy & physics classes. I think it would be fun to do in one of those classes but I’d really love to do this in a Trig or geometry class as it’s applied math. I think students that have a hard time looking at pictures of math problems often “get it” more when lining up how the mirrors need to be and thinking on why. I like the teamwork that they can use to get 3-4 mirrors lined up. In fact it might be fun to see who can get an alarm system covering the largest area or most sensitive to tripping the alarm.


This is probably my favorite activity so far, I really enjoyed the engineering aspects and the problem solving nature of the exercise.

If I were to teach this I would first do a mini project using mirrors and lasers and maybe putting the photo-resister at the end so students can see that the light from the laser is being reflected.

I feel the online walkthrough does a good enough job that most students could work through this without aid. However students will probably have difficulties with setting up the breadboard.

My role in all this would be to do a couple introductory activities beforehand to make sure all students have an understanding of the basic concepts we will be using.

A successful activity would look like students completing the task and able to do a write up explaining what they learned.


I love the idea of setting up a laser maze! The only difficulty I can foresee is that weak lasers cannot transmit very far without having the beam be lost.


I would probably use this with my technology club to make an alarm for the door.
My students would need helpwith the placing of pins.
the teacher monitors and encourages and asks the right questions to help them brainstorm.
Students are able to take this information and apply it to something else.


I can see using this in any of my classes. There is the coding that needs to be modify. And then setting up the mirror angle.

I think there will need to be some direct instruction at the very beginning where the students can ask questions. But the way its set up the students can work through it slowly and be able to work on their own.

I think with the direct instruction at the beginning and the way the activity is broken down I would still be mostly facilitating allowing the student to come up with their own way to set up the mirrors.

Student success would “look like” the students actually completing the activity. The would also have an understand of what they have accomplished and be able to adjust and/or modify to use is a “real” situation.


Great idea to add in the math concepts as well!


Yes–with the weaker lasers definitely setting up a smaller distance will be important to ensure success.


We’ve definitely seen that one of the challenges that STEM classes face is advancing from tools like Little Bits. You can explain to your students that now they get to work with tools that are used in real life products that are used every day!


Impressed with you using two mirrors! Great observation on loss of brightness with each mirror added and need to calibrate the threshold value.


Wow! I would have never thought of this! I think my 5th graders would be challenged, but would 100% love doing this as a challenge! I think there are a lot of applications we could use this with. We study balanced and unbalanced forces. They could even incorporate this is a part of our investigation we do using a marble run and investigating how the mass of objects affects the time it takes to travel. This could be the “finish line”. I’m excited to incorporate this into my curriculum!


I love this application!


As someone stated much higher in the thread, I see this having an awesome application related to student traffic throughout the school.

I have mentioned in previous threads that one big project I do involves the monitoring of a series of abiotic factors in our classroom. I would love to use this activity to try and gather data on movement through some specified areas of the school. I would love to then use that data to supplement our other readings.

How does student traffic in certain areas of the school affect our other readings?

I don’t see there being much in the way of difficulty for the boys. This is a rather straightforward activity with really clear instructions. (And the activity page starts with an ACE gif!)