In Part I of this series, I shared some images and thoughts about a set of projects I was providing to students at my sons’ school for an after-school class called Science for Young Makers. For this current batch of 28 students, I selected a set of projects that came from a book called Nick and Tesla’s Super-Cyborg Gadget Glove. The book is written by Bob Pflugfelder and Steve Hockensmith, and is the fourth book in a series that follows twins Nick and Tesla as they encounter various mysteries and build gadgets to help them in their investigations. The stories are fun, and the projects are perfect for younger makers.
In this particular book, the twins are trying to solve a mystery at a science museum and the projects all relate to a glove the kids. This glove has a number of features, and in Part I of this series I covered the first project that involved adding a super-bright LED to act as a flashlight. You can read Part I here, and see exactly what went into sourcing the parts and preparing it for the kids to tackle. Here in Part II, I’m going to discuss the next two items that were added to the glove — a very loud personal alarm and a 20-second voice recorder.
The Personal Alarm Project
With the LED flashlight project, the students wrapped a piece of exposed copper wire around their thumb. This would act as part of a circuit for activating the LED. The LED was glued onto the pointer finger knuckle (or near it) and a small coin battery was added to provide power. By touching pointer finger to thumb, the students closed the circuit and provided power to the LED.
The Personal Alarm cannot be powered by the small coin battery, however, so in addition to the alarm and its wiring, a 9V battery was needed to be added. Using double-sided tape, the students attached a 9V battery on the underside of the glove at the base of the wrist. 9V batteries aren’t cheap , and I was able to save some money by buying them in bulk at Costco at $15.00 for 8 batteries or about $1.88 each), but don’t forget to budget for a 9V battery if you attempt this project.
In addition to the 9V battery, the following items were needed for this project:
- small 90 decibel alarm
- two stripped wires, approx 4-6″ in length
- two wire nuts
- a 9V battery harness
I purchased a bunch of 9V battery harnesses from Amazon — total cost was $11.60 for 40 of them… shipping was free (Prime membership) so per-student cost was $0.29.
The alarm was a purchase made from eBay — again, make sure you investigate your seller. These were sold by a company out of Hong Kong BUT were shipped free from a USA location at a total cost of $34.95 for 50 of them… per-student cost of $0.70.
Note: Left over material is saved, and I have small baggies I’ve been collecting with parts/supplies to make an additional 12 gadget gloves. I’m hoping to repeat these projects at another school next semester, so I shouldn’t lose any money on the extra parts left over.
Wire nuts were bought at Home Depot in bulk — I use them often for my own projects, but they work out to about $0.10 each, and I have a small one and a larger one for each student. The small blue one is used for red wires (+V) and the larger (tan) wire nut is used for GND.
The alarms arrived, and the first thing I noticed was they didn’t have pre-soldered wires on them… very short (and stiff) wires about 1/4″ in length. Having the students solder wires wasn’t possible, and the small two-wire connectors (see Part I) would have worked but the leads on the alarms weren’t long enough to insert into the tunnels in the connector. This meant soldering on my own wires. I used 20 gauge wire… I like the thickness of the wires AND I like that they’re braided so I can twist them more easily with other wires. Total cost of the two wires was less than $0.10, but do add in a roll of wire to your budget. So far, with a 75′ roll of 20-guage wire, I’ve still got plenty of wire left for the 28 kids… more kids might mean buying an additional roll. Keep your receipt so you can return any unused rolls, obviously.
Each student was given a wire-and-alarm piece that they then placed on the top of the middle finger. An 1.5″ exposed bit of one of the wires was wrapped around the tip of the middle finger and hot glued at the very end of the wire to hold it in place. The other lead from the alarm was twisted with the red wire from the 9V battery harness. The black wire from the 9V battery harness was twisted into the wires covered by the tan wire nut (GND). This would allow the tip of the middle finger to be touched to the thumb and allow current to flow through the alarm. Just imagine the sound of 28 kids all setting off these alarms at once… yeah. After allowing each of them to test their alarm individually, I had them unplug the battery harness… to save my sanity.
Thus ended the personal alarm… up next was a project the kids (who had read the book) had been looking forward to for weeks — the 20-second voice recorder.
The Voice Recorder Project
A warning — the voice recorders are NOT cheap. Radio Shack sells them (if you’re lucky to find them) for $13 each plus tax. I found a place on eBay that sells them for about $8 each and purchased 35 for a total (with shipping) of $295.75 or a per-student price of $8.45. Definitely the most expensive item on the glove, but a project I felt I just couldn’t skip. That said, if you attempt this book’s projects for a large group of students, this may simply be too much money for you to budget. I’ve not found these little devices for a lower price, FYI.
The voice recorder device has four different wire-pairs coming out of it, and my students just loved how complex it looked. There’s a circuit board, a small speaker, a battery harness (9V) and a push button.
First things first — the 9V battery harness isn’t needed. You can clip it off (leaving as much left-over wire as possible) or have your students do it. Strip a 1/2″ or so to expose the wires. The book’s instructions are very clear and easy to follow here — you’ll be wiring the voice recorder into the existing 9V battery harness that was added for the Personal Alarm project. Remove the wire nuts and wire in the red wire to the +V wires (the one coming from the 9V battery and the wire from the alarm). The black wire from the recorder gets twisted into the GND wires (one of which comes from the thumb).
We hot glued the circuit board onto the back of the glove along with the speaker. The book shows the push button that records a message glued to the palm, but this push button has a long wire-pair and I let the students keep it unglued — they can tuck it inside the cloth that makes up the wrist covering of the glove OR they can glue it wherever they like. The other item that was glued to the glove, however, was the tiny microphone. We glued that to the ring finger.
The recorder works great — push and hold down the button and speak into the microphone. On the circuit board is a small gray button that plays back the recording when pressed. As you can imagine, the kids LOVED this. I let each of them test their glove and the wiring individually — I asked the students to be quiet and show respect and let each student record a personal message and then play it. All gloves worked right the first time! Woo Hoo!
Thoughts on Alarm and Voice Recorder Projects
With these three projects added (LED flashlight, Personal Alarm, and Voice Recorder), the glove is really looking cool. The kids want to keep wearing the gloves, even when we bring out the hot glue! (Note: DO NOT use hot glue on the gloves when the kids’ hands are in them!)
I have to admit that these gloves look amazing. Very cyborg-ish. The wires and batteries and wire nuts give them a very industrial look… not a polished product you’d find in the stores. I think most of the kids would agree that the exposed wiring really adds to the gloves’ appeal. Do note that for the kids (smaller) gloves, the speaker is glued more on the side of the glove… real estate on the top of the glove is very limited for these smaller kids gloves.
Do give your students warning about the loudness of the alarm. 90db is quite loud, and the high-pitched sound bothered a few students. I gave all the students firm warnings about NEVER triggering the alarm near someone’s ear… or a pet’s ears. We talked about decibels and I gave them different levels for things like normal voice, jet engine, lawnmower, and more. We chatted briefly about hearing damage and how our eyes and ears are so valuable. I further impressed upon them that they never shine the LEDs in someone’s eyes. We talked about light and lasers and how they can blind humans and animals — I think the kids have a good understanding of the dangers of light and sound and will (HOPEFULLY) use their gloves with care.
Total cost for the Personal Alarm was about $3.00 (9V, harness, wire, alarm, wire nut) and $8.45 for the Voice Recorder. At this point, total cost for these three projects (including glove) is floating at the $13.00 mark and we’ve got one more project to complete — the invisible ink UV LED reader. (Note: I haven’t included the cost of hot glue, electrical tape, or solder… if you don’t already have those, budget accordingly.)
Next week, I’ll wrap up this series with the UV LED project and offer up some suggestions for running a class. There’s not only the projects to perform, but there’s also the discussions of various science topics to go along with the glove projects. You can skip these, but I feel it’s important for the students to understand a bit about how the glove works as well as its components. More on that next week.
As always, if you have any questions about these projects just post it in the comments section and I’ll do my best to answer. My students have had a blast making their gloves, and I cannot wait for them to finish them and take home… although I suspect some parents might be questioning ever signing up their child again for one of my courses after they hear that personal alarm. Kidding. Maybe.