Solar Powered Circuit Waters Your Plants

November 9, 2014 by Rick Osgood 28 Comments

If you want your plants to stay healthy, you need to make sure they stay watered. [Dimbit] decided to build his own solar powered circuit to help automatically keep his plants healthy. Like many things, there is more than one way to skin this cat. [Dimbit] had seen other similar projects before, but he wanted to make his smarter than the average watering project. He also wanted it to use very little energy.

[Dimbit] first tackled the power supply. He suspected he wouldn’t need much more than 5V for his project. He was able to build his own solar power supply by using four off-the-shelf solar garden lamps. These lamps each have their own low quality solar panel and AAA NiMH cell. [Dimbit] designed and 3D printed his own plastic stand to hold all of the solar cells in place. All of the cells and batteries are connected in series to increase the voltage.

Next [Dimbit] needed an electronically controllable water valve. He looked around but was unable to find anything readily available that would work with very little energy. He tried all different combinations of custom parts and off-the-shelf parts but just couldn’t make something with a perfect seal. The solution came from an unlikely source.

One day, when [Dimbit] ran out of laundry detergent, he noticed that the detergent bottle cap had a perfect hole that should be sealable with a steel ball bearing. He then designed his own electromagnet using a bolt, some magnet wire, and a custom 3D printed housing. This all fit together with the detergent cap to make a functional low power water valve.

The actual circuit runs on a Microchip PIC microcontroller. The system is designed to sleep for approximately nine minutes at a time. After the sleep cycle, it wakes up and tests a probe that sits in the soil. If the resistance is low enough, the PIC knows that the plants need water. It then opens the custom valve to release about two teaspoons of water from a gravity-fed system. After a few cycles, even very dry soil can reach the correct moisture level. Be sure to watch the video of the functioning system below. Continue reading “Solar Powered Circuit Waters Your Plants” →

Inexpensive AVR Programmer Made From Five Components

November 2, 2014 by Rick Osgood 38 Comments

If you want to program an AVR chip as inexpensively as possible, then [Ian’s] solution might just be for you. He built an AVR programmer using only four components. This design is based on the vusbtiny AVR programmer design, with a few components left out.

[Ian’s] design leaves out two of the resistors and two diodes, leaving just four components. These include a 1.5k resistor, a small capacitor, a USB connector, a six pin header, and an ATtiny45. He admits that this may not be exactly up to USB spec, but it does work.

This is one of those projects that is really an exercise in “will it work?” more than anything else. The fact that you need to first program an AVR chip means that this wouldn’t be useful in a pinch, because you would already have to have a working programmer. Nonetheless, it’s always fun to see what can be done with as little as possible.

MacGyvered Optoisolator Is A Great Introduction

October 10, 2014 by Rick Osgood 17 Comments

Sometimes the best way to learn about a technology is to just build something yourself. That’s what [Dan] did with his DIY optoisolator. The purpose of an optoisolator is to allow two electrical systems to communicate with each other without being electrically connected. Many times this is done to prevent noise from one circuit from bleeding over into another.

[Dan] built his incredibly simple optoisolator using just a toilet paper tube, some aluminum foil, an LED, and a photo cell. The electrical components are mounted inside of the tube and the ends of the tube are sealed with foil. That’s all there is to it. To test the circuit, he configured an Arduino to send PWM signals to the LED inside the tube at various pulse widths. He then measured the resistance on the other side and graphed the resulting data. The result is a curve that shows the LED affects the sensor pretty drastically at first, but then gets less and less effective as the frequency of the signal increases.

[Dan] then had some more fun with his project by testing it on a simple temperature controller circuit. An Arduino reads a temperature sensor and if the temperature rises above a certain value, it turns on a fan to cool the sensor off again. [Dan] first graphed the sensor data with no fan hooked up. He only used ambient air to cool things down. The resulting graph is a pretty smooth curve. Next he hooked the fan up and tried again. This time the graph went all kinds of crazy. Every time the fan turned on, it created a bunch of electrical noise that prevented the Arduino from getting an accurate analog reading of the temperature sensor.

The third test was to remove the motor circuit and move it to its own bread board. The only thing connecting the Arduino circuit to the fan was a wire for the PWM signal and also a common ground. This smoothed out the graph but it was still a bit… lumpy. The final test was to isolate the fan circuit from the temperature sensor and see if it helped the situation. [Dan] hooked up his optoisolator and tried again. This time the graph was nice and smooth, just like the original graph.

While this technology is certainly not new or exciting, it’s always great to see someone learning by doing. What’s more is [Dan] has made all of his schematics and code readily available so others can try the same experiment and learn it for themselves.

THP Hacker Bio: Rusty Jehangir

September 5, 2014 by Brian Benchoff 18 Comments

[Rusty]’s project for the Hackaday Prize is extremely ambitious. He’s planning on sending an autonomous craft across the ocean, from LA to Hawaii, a distance that will end up being well over 2,500 miles The best part about this project? It’s already had some time in the ocean, cruising off the coast of southern California under its own power for a distance of 20km.

Why is [Rusty] doing this? Partly because he wanted to do something no one had ever done before. For him, this meant developing a cheap underwater thruster, building an autonomous solar-powered surfboard for a months-long voyage halfway across the Pacific. It’s a small step to the goal of exploring the deep ocean with his thruster and mostly off the shelf parts, but already [Rusty] has learned a lot about electronics in a marine environment and being confident enough to let a project go on its own for months at a time.

Interview below.

Continue reading “THP Hacker Bio: Rusty Jehangir” →

Solderless Noise-o-Tron Kit Makes Noise At Chicago Makerfaire

May 13, 2014 by Rick Osgood 37 Comments

Noise-o-Tron

Anyone who’s manned a hackerspace booth at an event knows how difficult it can be to describe to people what a hackerspace is. No matter what words you use to describe it, nothing really seems to do it justice. You simply can’t use words to make someone feel that sense of accomplishment and fun that you get when you learn something new and build something that actually works.

[Derek] had this same problem and decided to do something about it. He realized that in order to really share the experience of a hackerspace, he would have to bring a piece of the hackerspace to the people. That meant getting people to build something simple, but fun. [Derek’s] design had to be easy enough for anyone to put together, and inexpensive enough that it can be produced in moderate quantities without breaking the bank.

[Derek] ended up building a simple “optical theremin”. The heart of this simple circuit is an ATTiny45. Arduino libraries have already been ported to this chip, so all [Derek] had to do was write a few simple lines of code and he was up and running. The chip is connected to a photocell so the pitch will vary with the amount of light that reaches the cell. The user can then change the pitch by moving their hand closer or further away, achieving a similar effect to a theremin.

[Derek] designed a simple “pcb” out of acrylic, with laser cut holes for all of the components. If you don’t have access to a laser cutter to cut the acrylic sheets, you could always build your own. The electronic components are placed into the holes and the leads are simply twisted together. This allows even an inexperienced builder to complete the project in just five to ten minutes with no complicated tools. The end result of his hard work was a crowded booth at a lot of happy new makers. All of [Derek’s] plans are available on github, and he hopes his project will find use at Makerfaires and hackerspace events all over the world.

Custom Nixie Tube PSU Is A Lesson In Good PCB Design

May 11, 2014 by Rick Osgood 25 Comments

Nixie HVPSU

[Jan Rychter] was sick and tired of not being able to find the right power supply for his Nixie tube projects, so he decided to design his own. [Jan] started out designing around the MAX1771 (PDF) DC-DC controller, but quickly discovered he was having stability problems. Even after seven board revisions, he was still experiencing uncontrolled behavior. He ended up abandoning the MAX1171 and switching to the Texas Instruments TPS40210. After three more board designs, he finally has something that works for him. [Jan] admits that his design is likely not perfect (could have fooled us!), but he wanted to release it to the world as Open-Source Hardware to give back to the community.

The end result of [Jan’s] hard work is a 5cm x 5cm board that generates four separate output voltages from a single 12V source. These include both a 3.3V and 5V output for digital logic as well as a 220V out put for Nixie tubes and a 440V maximum output for dekatrons. The circuit also features several safety features including over-current protection, thermal shutdown, and slow-start. Be sure to check out [Jan’s] webpage to view out the schematics and technical information for this awesome circuit.

Need some Nixie tubes to go with that circuit? We know some resources for you to check out. Or you could always just build your own. How can you use this board in your next project?

Hackaday Links: May 4, 2014

May 4, 2014 by Brian Benchoff 8 Comments

We’ve seen a few builds from the Flite Test guys before, like a literal flying toaster, airsoft guns mounted to planes, and giving an electric plane an afterburner (that actually produced a little extra thrust). Now the Flite Test crew is gearing up for the Flite Fest, an all things remote-controlled flight convention in Malvern, Ohio during the last weekend in July. Seems like a pretty cool way to spend spend a weekend.

Unless you get one of those fancy resistor kits where every value has its own compartment in a case or plastic baggie, you’ll soon rue the day your loose resistors become disorganized. [Kirll] has an interesting solution to hundreds of loose resistors: packaging tape. If you want a resistor, just grab a pair of scissors.

Okay, these Adafruit “totally not Muppets™” are awesome. The latest video in the Circuit Playground series is titled, “C is for Capacitor“. There’s also “B is for Battery“, because when life gives you lemons, light up an LED. Here’s the coloring book.

A few years ago, a couple of people at the LA Hackerspace Crashspace put together an animated flipbook device – something between a zoetrope and the numbers in those old electromechanical clocks – and launched a kickstarter. Now they’re putting on a show, presented by Giant Robot, featuring the animated art of dozens of artists.

Vintage electronics? Yes. Vintage Soviet electronics? Here’s 140 pages of pictures, mostly of old measurement devices.