DIY Touch Sensor. How-To: Make a digital synthesizer. This week’s How-To comes from our newest contributor: Logan Williams. This simple guide will show you how to build a digital synthesizer that generates and manipulates square waves. Your synthesizer will have one oscillator, which produces a variable pitch controlled by a potentiometer, as well as an LFO which modulates that pitch at a variable frequency. The part count for this project is quite low, and it can be built for under $20. Finding the Parts The first step in building this digital synthesizer is to procure the parts that you will need. Not Pictured Tools Note: The potentiometers and audio jack must be either taped or soldered to 22 AWG solid core wire. Creating an oscillator Before we can begin with the digital synthesizer, we must generate the correct voltage.
The most basic circuit in any synthesizer is the oscillator. The problem is that it oscillates much too fast. To build the oscillator, assemble the schematic below on a breadboard. Controlling the oscillator Creating an LFO. Ultrasonic Range Finder with an ATtiny85 (With Shield) Now that you’ve put the Arduino into its Programming state, and connected the shield, it’s time to program the ATtiny85 chip, now I’ll show you how to make the LED on the board blink.
Go to this link and follow those instructions to get the core library for ATtiny’s loaded into the Arduino IDE, Once you’ve done that then copy the code below into the IDE and upload it (Once you’ve selected the correct board.) Hear with Ultrasound Using a DIY Flanagan 'Neurophone' UPDATE: Neurophone inventor Patrick Flanagan has since confirmed this design CAN produce Neurophone effects, though it's still probably not as good as the real thing. Some research suggests this is why: TL494's square-wave output gets differentiated by the piezos (which are capacitors), producing a "Lilly wave"-like signal that mimics signals produced by nerves. (The Lilly Wave, as far as I understand, is a sharp positive spike followed by an equal but negative one. The idea is the first peak transports something, I think ions, across the barrier between nerves while negative spike brings them back so the nerves can use them again.)
Overall, I did get it pretty wrong. Also, it turns out "earplug-style" in-ear-monitor headphones produce some of (but probably not all) of the same effects a Neurophone does. By mixing an audio signal with ultrasound, you can hear the audio as if it's inside your head... even if the 'headphones' are nowhere near your ears. Have a look at the schematic. Ultrasonic Tape Measure. Arduino $17.60 (Duemilanove 2009) ebay.com HC-SR04 Ultrasonic $ 4.61 ebay.com LCD Keypad (Arduino) $ 8.88 ebay.com Now I realize this is about $30 where the Stanley is available for around $24 but these parts are not committed to one function like the Stanley is.
Parts selection: I wanted an Arduino that was shield compatible. I already have two, a Freeduino and Seeduino so I decided to buy a third. Right now, one of the best deals I liked is for a standard Arduino Duemilanove 2009 on ebay. The LCD keypad also has Arduino support plus five user pushbuttons and a 16x2 (16 characters x two rows) display. Ping Organ. Ultrasonic Batgoggles. Wish you were bat? Want to Experience Echolocation? Want to try to "see" with your ears?
For my first Instructable, I will show you how to build your own ultrasonic batgoggles using an Arduino microcontroller clone, Devantech ultrasonic sensor and welding goggles for around $60 or less if you already have standard electronics components. You could also skip the electronics and make a simple bat-mask perfect to wear to the next Batman movie. In that case, the cost would only be about $15.
These goggles allow you to experience what it is like to use auditory cues like a bat and is intended for children in a science center setting to learn about echolocation. The goal was to keep costs as low as possible, avoid making the form of the interaction to be generic or unrelated to its educational purpose and to ensure that the physical form of device embodies the subject matter. Overriding PSU Safety Features. So I have one of those computer PSUs that I converted into a "bench power supply;" not really that elegant, but it does the job.
However, when I pull too much amps from it, it shuts off. This is a good thing, but one annoying part of it is that I have to disconnect the green wire from ground to reset the safety feature. Especially annoying when both my hands are occupied, holding wires to a capacitor. I did the only sensible thing and overrode that safety feature, with the help of a certain programmable chip. My very professional-looking schematic of the circuit. Pin 1 - D/C Pin 2 - Input - Button with pull-down resistor (1KΩ Brown Black Red) Pin 3 - Input - Red Wire (+5 VDC from PSU) Pin 4 - Ground Pin 5 - D/C Pin 6 - Output - Status LED Pin 7 - Output - Green Wire (PSU Power control) Pin 8 - Vcc - Purple Wire (It provides +5 VDC even if the PSU is "off") Prototype stage Perfboard stage When I just press the button, the PSU turns on, no safety features overridden. How to design and build a combat robot. Combat robots come in many sizes from 75grams to 340lbs each one of them has their pros and cons.
The first thing to do when thinking about building is to find the competition which you want to compete and see what weight classes are going to be there, because what is the point of building a bot you can never fight. Listing of robotic competitions are available on and Large robots: 60lbs + There is nothing like the thrill of seeing two large machines hitting each other with the force of a small car wreck. When most people think of combat robots it is these larger machines which first cross your mind. If you are fortunate to live near one of the large robotic events these machines can be fun builds, but at the same time the level of engineering required can be quite difficult. On the good side of larger machines is that many times you can find surplus parts online which can reduce the cost of the machine. Small Robot: Easy AM Transmitter! Basic Simple Bots Electronics. The next very important consideration to keep in mind is that electricity must be used. In other words, there needs to be something wired between positive and ground that adds resistance to the flow of electricity and uses it up.
If positive voltage is connected directly to ground and does not first pass through something that adds resistance, like a motor, this will result in a short circuit. This means that the positive voltage is connected directly to ground. When positive voltage is connected directly to ground, your battery will get painfully hot and, after a while, may do something bad like leak nasty burning chemicals. It is very important to prevent short circuits by making sure that the positive voltage is never wired directly to ground.
Note: A switch does not add resistance to a circuit and simply adding a switch between power and ground will create a short circuit. Security System Power Saver. Ericbarch « The Tech Junkies. In this episode of The Tech Junkies, we follow up with our prior solar installation and show how to add pre-built solar panels to a shed. A new solar panel is born – More Power! As we learned from our feedback, solar cells must all be of the same size/power capacity to hook them in series properly. In the original solar panel we had snapped our third row of cells in half to get them to fit down the remaining glass and make it easy to solder together. That essentially limits the current output of the entire panel because the full size cells are choked by the limited current that can pass through the snapped cells.
So we built another panel using all complete cells. It made it take a little longer wiring the cells together since we couldn’t just run down the straight line of them all, but we found that using tabbing wire for everything worked good. Laying out the new solar panel Read the rest of this entry » Make sure to read both the Wind Turbine Build and the Solar Panel Build.