Line Follower has Lots of recycled Parts, but Zero Brains

Line Followers are a tried-and-true type of robot; both hardware and software need to be doing their job in harmony in order to be successful at a clearly defined physical task. But robots don’t always have microcontrollers and software, as [Mati_DIY]’s zero programming analog line follower demonstrates.

For readers used to seeing a Raspberry Pi or Arduino in almost everything, an analog robot whose “programming” exists only as a harmony between its discrete parts can be an eye-opener as well as an accessible project. A video of the robot in action is embedded below.

[Mati_DIY]’s design uses two CNY70 reflective sensors (which are essentially infrared emitter/phototransistor pairs) and an LM358 dual op-amp. Together, the sensors act as two near-sighted eyes. By using the output of each sensor to drive a motor via a transistor, the presence or absence of the black line is directly and immediately reflected by the motion of the attached motor. The more black the sensor sees, the more the motor turns. Electrically, that’s all that happens; but by attaching the right sensor to the left motor and the left sensor to the right motor, you get a robot that always tries to keep the black line centered under the sensors. Playing with the spacing of the motors and sensors further tweaks the performance.

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Delta 3D Printer Made From Unorthodox Parts

Over here at Hackaday, we love stuff made from other (unrelated) stuff. Maybe it’s the ingenuity behind the build or the recycling of parts… or it could be both. Either way, it’s cool and a side benefit of re-using parts from the junk drawer is that it keeps the project cost down, maybe enough that the project wouldn’t even be feasible without the re-use of parts.

That brings us to the topic of this post, a Delta-style 3D Printer made from recycled parts not typically seen in such a machine. It was built by DIYer [hesamh] and is almost unrecognizable visually. The usual extruded aluminum or precision shaft frame has been replaced with 5 pieces of MDF, finger-jointed together at the seams. Attached to the 3 vertical MDF frame pieces are rail and carriage assemblies scavenged from Epson dot matrix prints saved from the scrap yard. The best part is that these rail/carriage assemblies already had stepper motors and belts installed!

The end effector is also unique among delta-style printers. This one is made from aluminum plate and provides a mount for the extruder. There is no need for a bowden tube setup when the extruder is mounted on the end effector, although the increase in mass may reduce the printer’s top speed. That’s fine by us as we’d rather have a good-looking slow print than a fast ball of spaghetti. Another scavenged stepper motor is used for the extruder. The accompanying belt pulley acts as a direct drive feed gear.

The print bed is a re-purposed flatbed scanner. The guts were removed and a heating element was placed under the glass. The bed heater is controlled separately by way of a household thermostat. An Arduino Leonardo and 4 stepper drivers replace the normally used Mega/RAMPS/Pololu combo. Overall, this is a cool build that shows what is possible with a little thought and resourcefulness. The only part used in this build that was actually made for use in a 3D Printer is the hotend!

Recycled clock spins round and round to tell time


[duckcrazy] recently shared the details on a clock he built, using recycled components to tell time.

He began his project by dismantling a handful of carefully selected pop bottles and an old clock. The bottom and midsection of the bottles were saved, and he verified that they could be easily inserted within one another. The base of the clock is made up of a CD, on which the clock’s motor components were mounted.

He constructed two open paper cylinders bearing hour and minute designations, then glued the respective clock hands inside. The cylinders and clock hands were re-mounted onto the clock’s motor, and the entire thing was enclosed within the pop bottles.

It’s a novel way to build a clock, and moving beyond the plastic bottles and paper for a moment, there’s a lot of potential for some even cooler designs based on his work. We imagine that laser-etched cylinders powered by a micro and a continuous rotation servo would be pretty sweet, though that’s just the tip of the iceberg.

Cheap and easy PCB agitator from an old CD-ROM


Instructables user [mzsolt] enjoyed making his own PCBs, but he wanted to speed up the etching process just a bit. While some people put together elaborate bubble tanks and agitators, he wanted to keep his simple and more importantly, cheap.

He looked around the house and discovered an ancient CD-ROM drive that was collecting dust, which he figured would make a great agitator for smaller projects. He picked up a decade counter and a handful of other cheap components, then got busy pulling the drive apart. He connected the motor and the drive’s limit switches to the decade counter, which controls the entire setup.

When powered on, the drive ejects, taking his container full of etchant with it. When the drive hits the outer limit switch, the decade counter reverses the motor until it hits the inner switch, reversing the motor once again.

As you can see in the video below, it works reasonably well. He suggests using a variable power supply to regulate the motor’s speed, but a variable pot would probably work just as well. Obviously the agitator is best suited for smaller projects, but since it was so cheap to put together, you won’t hear us complaining.

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NES game pad guided robotic arm


Instructables user [Bruno] sent in his most recent creation, a robotic arm controlled using an old NES game pad. He scavenged the majority of his parts from a pair of old HP printers, including motors pulleys, belts and more. In fact, most of the metal and plastic components that he used come from the old printer chassis as well. He has included copies of the templates he used when manufacturing both the plastic and metal components, which should come in handy should anyone try to replicate his work.

[Bruno] also included all of the source code for the robotic arm and mentions that the project required two PICs due to pinout requirements. He ultimately decided to use two cheaper models over a single more expensive unit that would have supplied all of the pins he needed. His cost conscious build is impressive and undoubtedly demonstrates just how many old components can be reused in new projects if you really put some thought into it. Great job with this build, keep up the good work!

Be sure to keep reading to see some video of the arm in action.

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Econo Monome

[Mike] really liked the thought of the Monome, especially the green aspect of their construction. He felt he could take it a step further. After 40 years of electronics tinkering, he had quite a spare parts box. He constructed his monome clone from stuff he just had laying around.  All of his pieces were either rejected samples from his company or outdated parts destined for the trash bin. Great job [Mike]. If you are planning to build one and don’t have the buttons laying around, you can get a more typical monome look and feel by going with the sparkfun RGB pads, like we did back in March.

[via Makezine]