arduino

2896 Articles

Water Tank Monitoring System Is Now Slug-Proof

January 21, 2015 by 24 Comments
[Peter] is doing his part toward protecting the environment and conserving water. He’s built a rainwater collection system complete with an underground storage tank. Since he wanted to monitor the water level in the tank, he made a level indicating system. Everything was going well until one day out of nowhere it stopped working, only returning 0’s as the level. [Peter] took a look and found that I slug had made its way into the electronics enclosure and slimed up the traces on the PCB, causing short circuits.To fix the problem [Peter] decided to redesigned the system. This time it would be built into an all-weather electrical box. The system uses a standard hobby ultrasonic range finder to measure the distance from the top of the tank to the level of the water. Two holes cut into the electrical box allow the sender/receiver components to peek outside of the enclosure. Any gaps were then filled with sealant. [Peter] also added a thermistor to measure the temperature inside the tank.The sensor values are read by an Arduino and sent wirelessly to [Peter]’s computer via a pair of XBee’s and a second Arduino with an ethernet shield. The data are sent in 3 minute intervals and automatically stored in a MySQL database for quick reference of level and temperature trends. Now [Peter] can monitor his rain water remotely and adjust his usage habits accordingly. Want to read more about water tanks? Check out this overflow monitor system.

A Portable KIM-1

January 20, 2015 by 26 Comments

The KIM-1 was the first computer to use the 6502, a CPU that would later be found in the Apple, Ataris, Commodores, and the Nintendo Entertainment System. Being the first, the KIM-1 didn’t actually do a whole lot with only 1k of ROM and a bit more than 1k of RAM. This is great news for anyone with an Arduino; you can easily replicate an entire KIM-1, with a keypad and 7-segment display. That’s what [Scott] did, and he put it in an enclosure that would look right at home in a late 70s engineering lab.

The impetus for this build was [Scott]’s discovery of the KIM-Uno, a kit clone of the KIM-1 using an Arduino Pro Mini. The kit should arrive in a few weeks, so until then he decided to see if he could cobble one together with parts he had sitting around.

Inside a handheld industrial enclosure is an Arduino Uno, with a protoshield connecting the keypad and display. The display is an 11-digit, seven-segment display [Scott] picked up at a surplus shop, and the metal dome keypad came from a hamfest.

Getting the software working took a bit of work, but the most important parts are just modifications to the standard Arduino libraries.

Now that [Scott] has a KIM-1 replica, he can program this virtual 6502 one hex digit at a time, run Microchess, or use the entire thing as a programmable calculator.

LED Matrix Infinity Mirror

January 20, 2015 by 12 Comments

[Evan] wrote in to let us know about the LED matrix infinity mirror he’s been working on. [Evan] built a sizable LED matrix out of WS2812B LEDs and mounted them to a semi-reflective acrylic sheet, which makes a pretty awesome infinity mirror effect.

Instead of buying pre-wired strands of serial LEDs like we’ve seen in some other projects, [Evan] purchased individual WS2812 LEDs in bulk. Since the LEDs just had bare leads, [Evan] had to solder wires between each of his 169 LEDs (with some help from a few friends). After soldering up hundreds of wires, [Evan] drilled out holes for each LED in a piece of semi-reflective acrylic and inserted an LED into each hole.

To create the infinity mirror effect, [Evan] mounted the LED matrix behind a window. [Evan] put some one-way mirror film on the outside of the window, which works with the semi-reflective acrylic to create the infinity mirror effect. The LEDs are driven by an Arduino, which is controlled by a couple of free programs to show a live EQ of [Evan]’s music along with patterns and other effects.

HotWheels

DIY Hot Wheels Drag Race Timer

January 19, 2015 by 25 Comments

[Apachexmd] wanted to do something fun for his three-year-old son’s birthday party. Knowing how cool race cars are, he opted to build his own Hot Wheels drag race timer. He didn’t take the easy way out either. He put both his electronics and 3D printing skills to the test with this project.

The system has two main components. First, there’s the starting gate. The cars all have to leave the gate at the same time for a fair race, so [Apachexmd] needed a way to make this electronically controlled. His solution was to use a servo connected to a hinge. The hinge has four machine screws, one for each car. When the servo is rotated in one direction, the hinge pushes the screws out through holes in the track. This keeps the cars from moving on the downward slope. When the start button is pressed, the screws are pulled back and the cars are free to let gravity take over.

The second component is the finish line. Underneath the track are four laser diodes. These shine upwards through holes drilled into the track. Four phototransistors are mounted up above. These act as sensors to detect when the laser beam is broken by a car. It works similarly to a laser trip wire alarm system. The sensors are aimed downwards and covered in black tape to block out extra light noise.

Also above the track are eight 7-segment displays; two for each car. The system is able to keep track of the order in which the cars cross the finish line. When the race ends, it displays which place each car came in above the corresponding track. The system also keeps track of the winning car’s time in seconds and displays this on the display as well.

The system runs on an Arduino and is built almost exclusively out of custom designed 3D printed components. Since all of the components are designed to fit perfectly, the end result is a very slick race timer. Maybe next [Apachexmd] can add in a radar gun to clock top speed. Check out the video below to see it in action. Continue reading “DIY Hot Wheels Drag Race Timer” →

Arduino Calculator

High Cost Arduino Calculator Is Unwieldy, Still Cool Though

January 19, 2015 by 9 Comments

One of [Kale_3D]’s teachers had made an Arduino-powered calculator. It wasn’t robust and didn’t last too long in the classroom environment. After the non-functional calculator sat around the class for a while, [Kale_3D] decided he would give a shot at repairing it. Along the way the project didn’t just get repaired, it got a full rebuild.

This calculator uses a full 16 button matrix keypad. The Arduino deciphers button pushes with the help of the Keypad library, at which time the appropriate character is displayed on the 2×8 LCD screen. Selecting the function is a little different from normal since this project is limited to 16 buttons. Two of the buttons allow scrolling through not only standard arithmetic functions but trigonometric functions also. This was one of the features that the previous version was not capable of.

To protect the components, an enclosure was made out of 1/4″ laser cut wood. The pieces have notched edges to permit a nice fit. Even so, corner blocks were added to give the case even more rigidity.

Yes, this calculator is not practical, but that’s not the point. In the end [Kale_3D] felt that the project was definitely worth doing. He had learned a bunch of stuff about Arduino and especially code debugging! Most important of all he had a good time building it. There’s a video after the break showing how it works. The code and wiring diagrams are available for download on the project’s Instructable page.

Continue reading “High Cost Arduino Calculator Is Unwieldy, Still Cool Though” →

Dial

Dial Is A Simple And Effective Wireless Media Controller

January 17, 2015 by 26 Comments

[Patrick] was looking for an easier way to control music and movies on his computer from across the room. There is a huge amount of remote control products that could be purchased to do this, but as a hacker [Patrick] wanted to make something himself. He calls his creation, “Dial” and it’s a simple but elegant solution to the problem.

Dial looks like a small cylindrical container that sits on a flat surface. It’s actually split into a top and bottom cylinder. The bottom acts as a base and stays stationary while the top acts as a dial and a push button. The case was designed in SOLIDWORKS and printed on a 3D printer.

The Dial runs on an Arduino Pro mini with a Bluetooth module. The original prototype used Bluetooth 2.0 and required a recharge after about a day. The latest version uses the Bluetooth low energy spec and can reportedly last several weeks on a single charge. Once the LiPo battery dies, it can be recharged easily once plugged into a USB port.

The mechanical component of the dial is actually an off-the-shelf rotary encoder. The encoder included a built-in push button to make things easier. The firmware is able to detect rotation in either direction, a button press, a double press, and a press-and-hold. This gives five different possible functions.

[Patrick] wrote two pieces of software to handle interaction with the Dial. The first is a C program to deal with the Bluetooth communication. The second is actually a set of Apple scripts to actually handle interaction between the Dial and the various media programs on his computer. This allows the user to more easily write their own scripts for whatever software they want. While this may have read like a product review, the Dial is actually open source! Continue reading “Dial Is A Simple And Effective Wireless Media Controller” →

Alarm1

Adding WiFi And SMS To An Alarm System

January 16, 2015 by 17 Comments

[Don] wanted to bring his alarm system into the modern age. He figured that making it more connected would do the trick. Specifically, he wanted his alarm system to send him an SMS message whenever the alarm was tripped.

[Don] first had to figure out a way to trigger an event when the alarm sounds. He found a screw terminal that lead to the siren. When the alarm is tripped, this screw terminal outputs 12V to enable the siren. This would be a good place to monitor for an alarm trip.

[Don] is using an Arduino nano to monitor the alarm signal. This meant that the 12V signal needed to be stepped down. He ran it through a resistor and a Zener diode to lower the voltage to something the Arduino can handle. Once the Arduino detects a signal, it uses an ESP8266 WiFi module to send an email. The address [Don] used is the email-to-SMS address which results in a text message hitting his phone over the cell network.

The Arduino also needed power. [Don] found a screw terminal on the alarm system circuit board that provided a regulated 12V output. He ran this to another power regulator board to lower the voltage to a steady 5V. This provides just the amount of juice the Arduino needs to run, and it doesn’t rely on batteries. [Don] provides a good explanation of the system in the video below. Continue reading “Adding WiFi And SMS To An Alarm System” →