Hobby grade R/C cars with high voltage batteries require some form of voltage regulation. The batteries in those vehicles are typically 11.1V to 22.2V, while the required voltage for the radio system components is 6.0V to 7.4V depending on their ratings. Current draw with some of these systems normally ranges from 3A to 6A, as well. Some electronic speed controls in the R/C industry have this capability, but many do not, and it is a common point of failure for those that do.
This circuit provides the necessary regulation and power supply for high powered R/C systems common today. The center of the circuit is the RT8298, a synchronous high voltage Buck Converter that can support the input voltage range from 4.5V to 24V and the output current can be up to 6A. The voltage dividers that set the output voltage to 6V or 7.4V are controlled by a simple switch that the user sets to the voltage they want.
R/C Car Voltage Regulator – [Link]
Voltset connects to smart devices and turns them into smart multimeters, allowing you to tinker, learn and collaborate with electronics.
Voltset is a module that plugs into a smartphone via a USB connection. It will then turn a smartphone into a smart multimeter. The multimeter is a must have tool for every DIY, tinkerer or hardware hacker. This project was started two years ago by two makers, Michael and Tom. They could not find a multimeter that was convenient to carry, yet powerful and versatile enough to be useful in their wide range of projects. So they set out to build their own. Almost two years later, they are ready to introduce Voltset to the world of makers.
Voltset – World’s Smartest Multimeter for Smart Devices - [Link]
by Tony Keith:
You have a project that accepts commands using a 16 button keypad and want to perform validation on the commands as each character is typed. But how? Use state machine logic / programming to solve the problem. If you aren’t familiar with or haven’t used state machine logic in programming, it is the easiest way to to break complex problems into manageable states and state transitions especially for handling serial input. One of the easiest ways to implement a state machine is to use a switch statement. In my opinion it is the only way to implement serial input commands.
Keypad Input Validation using State Machine Programming - [Link]
If you are doing any electrical work, one of these Non Contact Voltage Test Pens can be quite handy. Just touch the wire that you want to make sure isn’t live and check that the tester doesn’t beep and start flashing. This test pen is on all the time monitoring for AC between 90V and 1000 V. I would have preferred the device to have an on/off switch which would allow the battery to last even longer but I guess they figured that the 1.5 year life that they rate this for when in standby was good enough. This impressive life is because they got the current draw down to under 10 micro amps! Even when operating it only draws a handful of milli amps.
Non Contact Voltage Test Pen Teardown - [Link]
by Cabe Atwell @ edn.com
Every electrical engineer who does DIY projects knows that dozens of free resistor calculators are out there that can save quite a bit of tedious work. Other simple tools can be found, but traditionally the free tool arsenal would stop there. Sure, there are base platforms such as SolidWorks and Autodesk, but what happens when they are missing a feature needed at that exact moment?
Now we’re seeing a relative explosion in free tools for engineering electronics. It is easy just to hit the Net and use the myriad resources available. Some of those online tools prove to be worthless, and it’s back to blind searching or some paid tool, but free software extends far beyond the functionality of a simple calculator.
Top free DIY tools every EE needs - [Link]
To my computer, its simply a USB keyboard, nothing less, but to me its a remote I can use on any platform with no line of sight. I decided to name it the keyMote. Sounds a bit odd to my ears but its a fitting name.
Here is how it works. There are two parts to this system, the remote, which is battery powered, and the base, which is hooked up to a computer. The remote is a simple keypad (In the case of the prototype, its a numeric keypad, but really, it could be any interface) with a transmitter hooked up to it. The base, the other end, is a receiver with USB Human interface device functionality, in other words, a vanilla USB keyboard. When a button is pressed, the remote sends the identifier of that button to the base which then looks up in a table the keystrokes this identifier is mapped to and sends those to the computer via USB. What button is mapped to what keystroke is entirely configurable using a serial terminal interface (shell) to the base. It can be anything, Ctrl-C, Alt-Shift-F, PageUp, etc. Getting it to interface with your program is then simply a matter of configuring keyboard shortcuts.
keyMote: a simple wireless remote for computers - [Link]
VoCore is an open hardware runs OpenWrt. It has WIFI, USB, UART, 20+ GPIOs but size is only one inch. It helps you make a smart house or study embedded system.
VoCore is a coin-sized Linux computer with wifi. It is also able to work as a full functional router. It runs OpenWrt on top of Linux. It contains 32MB SDRAM, 8MB SPI Flash and using RT5350(360MHz MIPS) as its heart. It provides many interfaces such as 10/100M Ethernet, USB, UART, I2C, I2S, PCM, JTAG and over 20 GPIOs but its size is less than one square inch(25mm x 25mm).
VoCore: A coin-sized Linux computer with wifi - [Link]
A demonstration of the relative stability of the internal and external oscillators.
AVR Oscillator Stability - [Link]
Shabaz over at Element14 writes:
This post is about an interesting, low-cost sensor that doesn’t need much processing to use, and has some unique characteristics – a PVDF (polyvinylidene difluoride) Piezoelectric sensor. The sensors looks like a small strip of plastic, and can be used for detecting movement or vibrations even into ultrasound. Such devices can help sense in many practical, real-world scenarios. They are extremely sensitive, low cost and easy to use. Some simple practical experiments with these sensors are described, finally looking at detecting ultrasound.
Impact, vibration and ultrasound sensing with PVDF Piezo sensors - [Link]