In this project we'll be making "stupid" swarm bots that can be assembled in less than 10 minutes and cost less than $5 per bot. They are also extremely easy to make as there is no coding involved, no microcontroller, and no advanced circuitry. Vibrating motors cause these robots to move around, and when you make a few of these you will have created your own miniature swarm of minions to do as you bid! (Not really because they're actually pretty stupid and go where they please). Let's dive in!
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Step 1: What You'll Need for WORLD DOMINATION
Ok, maybe these robots won't take over the world as they basically just run around hitting things, but you'll still need a few things to build them:
3.7v 150 mAH or Similar Square LiPo Battery
These lithium-ion polymer batteries are small, rechargeable, just the right size to fit on a bottle cap, and can provide enough voltage and current straight out of the battery to power a few vibration motors. Here's an Amazon link for two batteries, but we only need one: LiPo Batteries from Amazon and another link from Adafruit: LiPo battery from Adafruit
2x Miniature Circular Vibration Motors
Believe it or not, these babies can actually pump out a fair amount of vibration. I've found that two per bot is enough to get them moving fast enough. Here's a lot of them for cheap: Amaon Link
2-Pin JST Connector
This will be the receptacle for the battery lead and will also serve as our on and off switch (plug and unplug battery lead). Here's a link to the one that fits best but is relatively expensive: Adafruit Link and here's a link to a cheap 120pc pack from Amazon that do not fit perfect but still work: Amazon Link
Small Bottle Cap
This will be the base for the lil' buzzing bot. Caps that are around an inch or two in diameter work the best, but as long as your cap is roughly the same size to mine it should be OK. The only important thing is to find a cap with a relatively shallow rim, such as from Aquafina water bottles.
Two Paper Clips
We'll cut these up to make the legs. I used the small variety.
LiPo Battery Charger
Here's what you'll need to build the bots:
Hot Glue Gun
Soldering Iron and optional soldering helper
Optional Spray Paint
Step 2: Build Those Bots!
This next part is actually fairly easy.
-Hot glue the battery to the top of the cap as shown in image 1
-Wrap and hot glue the lead around the side (image 2) leaving about as much unwrapped as shown in image 3
-Plug in the lead to the JST receptacle and figure out which header coming off of the receptacle is the ground and which is the voltage out
-Solder the voltage in (red) lead of each motor to the voltage out header on the JST connector. (Image 4)
-Solder the grounds on the motor to the ground header on the connector. You can turn off your soldering iron now, as we won't need it for anything else. (Image 4)
-Test the circuit by plugging the battery lead into the JST connector to see if the motors buzz.
-Insulate and secure the connections with a drop of hot glue if everything is OK. (Image 4)
-Hot glue the soldered connector in place to the bottom of the cap as shown in image 5.
-Secure the motors on top of each other with some hot glue, and place them in the center of the bottom of the bottle cap with more hot glue. (Image 6)
-Bend the two paper clips in a straight line and cut them down the middle as shown in images 6 and 7.
-Glue three of the legs in place as shown in image 8. It helps if you stick them inside the little lip found on the bottom of some bottle caps.
-Lastly, spray paint the bot as desired and adorn with googley eyes to make world domination that much more enjoyable and stylish.
-Repeat all steps until planet Earth is overrun by Buzzing Bottle Cap Bots. Recharge batteries when needed.
Step 3: Done!
If your robots look something like the one in the video above, then congratulations! You've successfully made your very own buzzing bottle cap bot! Please show your support by liking this instructable and commenting. More things to try:
-Adding more vibration motors: this can increase the robot's speed, to a point
-Adjusting the weight distribution: this can cause the robot to behave differently
-Adjusting the length of specific legs: having an imbalance in leg length can result in the same thing as above; different behaviors
-Adding an on/off switch: I didn't have any lying around but this might be a good idea. Just connect it to the positive lead of the LiPo battery.
Thanks for reading! I'll see you in my next instructable!