Jack O' Sentinel

Jack o' Sentinel is the upgraded version of Jack o' lantern, it looks like a cyborg pumpkin! or perhaps the terminator? who knows?!

Anyway, who or what comes close to our friend Jack o' Sentinel will be sensed, and jack will light up to scare away the trespassers.

This project is great if you're low on time or want to add a little extra to your pumpkin this Halloween.

As previously mentioned if you are low on time, this is a great project! Guess what, I haven't had much time to make this project all pretty and nice, so it was a bit trown together with "spit and tape".

I'll show you the ugly stuff, but first what you'll need:

1. Tape/duct tape/double side tape (yeah, "spit and tape" remember. Actually don't spit on it)
2. Pumpkin Jack (I bought a generic plastic one, short time remember, but you can make your own)
3. 1 arduino nano (can be a clone)
4. 1 WS2812B LED matrix (in this case 8x8)
5. Ultrasonic sensor (in my case the HC-SR04)
6. breadboard jumper wires
7. powerbank
8. and usb cable (programing and power)
9. Hot glue gun

To make a great project you should make a plan or a layout of your steps or procedures to develop your idea.

Well I took a quick look and figured out that I would route the cables to the back of the pumpkin where the original color changing LED assembly was mounted.

Then I started testing the lenght of the wires and connections to see if they would reach. Depending on your pumpkin you should test the lenght of the connections before gluing or taping anything.

Well, I selected one of Jack's eyes since it makes sense, right? And it will make it look like terminator pumpkin! *Schwarzenegger laugh*

After the great plan I devised... I connected f-f (female-female) jumper wires to the sensor and added m-f(male-female) wires to extend the lenght. I taped the connection zone with packaging tape (only tape I had avaible on hand)

Due to my already mentioned lack of time, I made a great job with the hot glue gun and just glued the ultrasonic sensor as straight as possible to the left eye and routed the cables to the hole in the back.

As simply as possible, I attached a bit of double side tape to the back of the matrix and hoped for the best.

yeah, exactly like that attach a bit of double side tape to the back and slap it in the inside of "Jack's guts" (inside the pumpkin of course!), just make sure the connections reach the hole in the back.

After this you can tape or hot glue the connections in the back. well I mixed and matched both but you know I just lacked the proper time to make it properly.

you're now questioning how come it look so nice in the thumbnail with so many "" done! Can't say the word. And yes I'm a bit ashamed of the "quality" or the lack of it. But this was the quickest I could build, after a long work day and before children would knock on my door asking for treat or trick.

Make the ultrasonic sensor connections to the Arduino nano:

(Sensor) Trig (trigger) to D9 (Arduino)

(Sensor) Echo to D8 (Arduino)

(Sensor) GND to GND (Arduino)

(Sensor) VCC to 5V (Arduino), 5V in the top header pins in this case

Make the LED matrix connections to the Arduino nano:

(Matrix) GND to GND (Arduino)

(Matrix) VCC to 5V (Arduino), 5V in the normal pins in this case

(Matrix) Data to D2 (arduino) but add a 220R resistor in between 2 jumper wires and make the connection.

And that's it, is that simple!

Yeah! Your project is almost done!

Well, not quite. Maybe for you, but not for me.

This was the part that took more time, since I had to create the code and test it. Not super hard or long code, but still took me a bit of testing and finding what would be the best light effects for added spookiness.

Upload the sketch and test it, you can ajust the distance for your requirements and the sensor detection range.

Note: The ultrasonic sensor as a cone of detection, and the further the detection range the more wide that cone is, so beware, it can be ativated by placing it near a wall or on a hallway.

Well, as you know it could help a bit to improve it's build quality. but if you're in a rush it is actually a quick and cool project to make.

If you need longer detection distances and to place your Jack o' Sentinel in a tight space it would be better to use a TOF sensor, but I'm afraid the cyborg look would no longer be a reality.

Other great upgrade would be to add sound effects, that would certanly increase the spookiness!

Have fun and experiment with this and other projects!