Lil’ ESP32 Bot Does Remote Surveillance, And It’s Easy

February 19, 2020 by Lewin Day 7 Comments

Digital cameras have been around for a long time, as have small remote control robotics platforms. However, combining the two has really only come into its own in the last decade or so, as more bandwidth has become available to the home tinkerer. This ESP32-CAM surveillance bot is a great example of what was once hard becoming trivially easy.

It’s a case of standing on the shoulders of giants. The ESP32-CAM is a device that allows one to stream live video images over a network using existing example code. In this case, it’s combined with an L298N DC motor driver which allows the Adafruit robot platform to be steered like a tank via its two wheels. A pair of SG90 servos then serve as a pan/tilt mechanism to further improve the robot’s field of view.

If you aimed to attempt this back in 2010, you’d have spent six months figuring out how to get a microcontroller to talk to a small camera module. Only then could you consider solving the multitude of other problems presented by getting the video feed off the bot to somewhere useful. These days, you can order a bunch of parts online and have it up and running in a couple hours. This project from 2013 serves as an example of how much things have changed in the intervening years. Video after the break.

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Simple 3D Printed Robotic Arm Uses Compliant Mechanism

February 9, 2020 by Danie Conradie 5 Comments

Learning through play is effective for humans of all ages, and since 2016 [slantconcepts] has been designing STEM kits that help teach kids to build their future overlords. They are launching version 3 of their LittleArm robotic arm, and the progression from version 1 is an interesting study in simplification and parts count reduction without sacrificing functionality.

In all of the LittleArm versions the main mechanical components are 3D printed, and driven by 3 servos for motion plus one additional servo to run the gripper. These kits are specifically intended to be built and disassembled repeatedly, and classrooms are a great place for small screws to easily disappear, so reducing the number of screws was a big goal for v3. The gripper/forearm shows the most dramatic improvement from the previous versions, being simplified from 8 separate components to a single 3D printed part by using a compliant mechanism — that squiggly pattern that allows the gripper to flex into place. The gripper tips also feature a simple “cutout” that allow it more easily grasp horizontal objects.

An Arduino Nano based expansion board is used to control the arm, with a HC-06 Bluetooth module to allow it to be controlled via a smart phone app. Various sensors can also be added to expand the kit’s capabilities. Unfortunately the mechanical design is not open source, but it can still be a source of inspiration for your own design projects.

Hopefully this kit will inspire some future hackers to build a more advanced 3D printed version, or even a giant hydraulic powered arm.

Rollbot Crams Ten Arms Onto One Wheel

February 6, 2020 by Donald Papp 9 Comments

It’s not every day that we see someone trying something new with robot locomotion, but [kong]’s robot Rollyboi was made to do exactly that by mixing up the usual robot-wheel-motor layout. Instead of the robot using motors to drive wheels, Rollyboi is itself the wheel, and uses multiple simple arms (legs?) attached to hobby servo motors to propel itself. The idea is that the arms swivel out one at a time to roll the robot along as needed.

It’s a novel idea, but how well does it work in practice? The first version was blind and mechanically unstable, with no idea which way was up and therefore no way to effectively control which arm needed to be extended, but was nevertheless able to roll along. The next version implemented a simple control system: buttons installed along the outside rim let the robot know how it is moving and which arm to extend next. With two sets of arms (one on each side) the robot becomes capable of executing simple turns by extending one arm more than the other.

In the end, Rollyboi could move but still lacks a means to perceive and navigate its environment. This is made more challenging by the fact that the robot’s body (and therefore any sensors mounted to it) would be in constant motion as the robot moves. Still, it’s interesting to see how far the idea went using only simple hardware, and its motion gives off a certain radial solenoid engine vibe. You can watch a brief video below.

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Robo Pony Greets Hackerspace Visitors

January 24, 2020 by Lewin Day 9 Comments

Robotic animal companions were once all the rage, though their limited personalities and annoying sound effects often relegated them to the bin fairly quickly. This makes them all the more ripe for hacking. [David Bynoe] had a Baby Butterscotch that was in need of a new home, and he decided to put the pony to work at his local hackerspace.

The Baby Butterscotch pony is a charming beast in stock form, yet highly menacing once its skin is removed. Mounted to a plaque, the pony has three PIR sensors that detect movement. These sensors are used to allow the pony to act as a door greeter, waking up when people enter the hackerspace and following them around the room. The additional hardware interfaces with the pony’s stock electronics by using floating capacitors and relays to activate the original capacitive touch sensors. The final piece is finished with a coat of gold paint and some RGB eyes to complete the look.

It’s a fun project that gives Vancouver Hack Space a little personality, and we’re sure it’s enjoyed by the members. We’ve seen other companion toy hacks before, with the Furby always being a ripe target for projects. Video after the break.

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Experiments In Soft Robotics

January 19, 2020 by Gerrit Coetzee 6 Comments

[Arnav Wagh] has been doing some cool experiments in soft robotics using his home 3D printer.

Soft robots have a lot of advantages, but as [Arnav] points out on his website, it’s pretty hard to get started in the same way as one might with another type of project. You can’t necessarily go on Amazon and order a ten pack of soft robot actuators in the way you can Arduinos.

The project started by imitating other projects. First he copied the universities who have done work in this arena by casting soft silicone actuators. He notes the same things that they did, that they’re difficult to produce and prone to punctures. Next he tried painting foam with silicone, which worked, but it was still prone to punctures, and there was a consensus that it was creepy. He finally had a breakthrough playing with origami shapes. After some iteration he was able to print them reliably with an Ultimaker.

Finally to get it into the “easy to hack together on a weekend” range he was looking for: he designed it to be VEX compatible. You can see them moving in the video after the break.

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The Internet Controls This Monster

January 6, 2020 by Rich Hawkes 5 Comments

What’s worse than unleashing a monster on the internet? Allowing the internet to control the monster! But that’s just what [8BitsAndAByte] did, created a monster that anyone on the internet can control. Luckily for us, this monster only talks.

This is a very simple project and most of the parts are off the shelf. Hardware wise the monster’s body is made out of a plastic flowerpot; its mouth is a bit of wood that covers the top of the flowerpot; its eyes, two halves of a plastic sphere painted white with some felt for irises. And then whole thing is covered in some blue fake fur.

Electronics wise, a Raspberry Pi is running the show and handling the text-to-speech is an AIY Voice Hat. A servo fits inside the flowerpot to open and close the monster’s mouth. On the software end of things, a bit of Python has been written that waits for a bit of text, sends it off to the Voice Hat’s text-to-speech module and moves the servo to open and close the mouth. The scary part, connecting the monster to the internet, is done with remo.tv, which is some open-source code hosted on GitHub specifically for allowing control of robots over the internet.

This is a neat little project which is simple enough that kids could build one themselves. The instructions and the python script are up on the Instructables page, and you can see the monster in action at its page on remo.tv. Perhaps [8BitsAndAByte] could add a couple of these internet controlled robot arms to the monster to create a monster that could create some real havoc!

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FET Based Motor Driver Is Better Than L298N

December 29, 2019 by Al Williams 20 Comments

If you want to build a small robot with a motor, you are likely to reach for an L298N to interface your microcontroller to the motor, probably in an H-bridge configuration. [Dronebot] has used L298N chips like this many times. In the video below, he uses a TB6612FNG instead, taking advantage of the device’s use of MOSFETs. The TB6612 may be a little more expensive, but it’s clearly worth it.

You can get breakout boards for the tiny chips. [DroneBot] looks at several ready-to-go breakout boards. They are not drop-in compatible, though. For example, the L298N can operate motors from 4.5 to 46V while the TB6612 can go from 2.5 to 13.5V on the motor voltage. The L298N also handles more current. However, because of its relatively low efficiency, it needs a heat sink. The TB6612 boasts up to 95% efficiency and also has a low current standby mode. Of course, the TB6612 drops much less voltage which is great if you are using low voltage motor.

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