Tips and Tricks | Embedded Lab

Category Archives: Tips and Tricks

RF detection using a common LED

Posted on April 26, 2015 by R-B Leave a comment

Hardware hacker b.kainka has posted on Hackaday.io a very interesting trick of detecting a RF signal using an everyday LED and ATtiny13 microcontroller (other microcontrollers should work too). I am using the ATtiny13 on the Sparrow board. https://hackaday.io/project/4926-cheepit-sparrow-dev-boards-for-smartphones LED2 is connected to port B.3 which is ADC(3) as well. So why not connect an Antenna here. The LED should work as a detector diode. A bias voltage is needed. So I should switch on the internal pullup. Now it works fine! Don’t believe it? Watch the video. To get it sensitive enough I had to use one more trick. I switch on

Improving PWM-to-Analog voltage conversion

Posted on April 22, 2015 by R-B One comment

Modern day microcontrollers are equipped with one or more dedicated PWM peripherals built-in that can be used to generate analog output voltages with varying range by just using a basic RC filter circuit. While this is a very simple and practical approach, it has some limitations such as it can only drive high impedance load and the processor should continuously output the PWM signal to maintain the output voltage constant, which prohibits the processor to be put into a low power shutdown state when required. This application note from Linear Technology describes the use of LTC644 and LTC2645 chips, which are dual

Making a high-altitude balloon cam

Posted on April 19, 2015 by R-B Leave a comment

Ray Visser posted an instructable on making a simple high-altitude balloon cam with minimal payload containing a smartphone to text its GPS location and a Canon Powershot digital camera to take pictures. High-altitude ballooning, or HAB, involves sending a payload of cameras, scientific instruments, or other items on a journey into the stratosphere, strapped to a weather balloon. When the balloon bursts, a parachute brings the payload gently back down, where it (and your data/photos/freeze-dried food) can be recovered! Most HAB systems are electronically complex, so we wanted to drastically simplify it. Our payload is only a smartphone designed to text

Tutorial on Thermocouple Amplifier

Posted on April 7, 2015 by R-B Leave a comment

Bill Herd at Hackaday has posted a new video tutorial on Thermocouple Amplifier that covers the most basic instrumentation required to interface a thermocouple to a microcontroller ADC channel for reliable temperature measurements. A thermocouple consists of a junction of two wires made of different metals and are characterized by a temperature coefficient that is required to convert the thermocouple output voltage to the sensed temperature. In addition, the thermocouple also needs to be calibrated to a reference temperature point. In his short tutorial, Bill explains a practical circuit to implement precise temperature readings from a thermocouple. Different thermocouples sensors

Turning an old Ardroid phone in to a WiFi webcam for remote monitoring

Posted on December 16, 2014 by R-B Leave a comment

If you have a spare Android phone lying around somewhere with no use, you would probably need to read this Instructable to turn it into an useful WiFi-enabled webcam that could be used for remote monitoring. The author explains the technique with Motorola Droid Razr Maxx Android device, and uses IP Webcam App for video feeding. IP Webcam allows you to view the WiFi webcam video inside your WiFi network without connecting to internet, as well as outside the WiFi through VLC player or web browser. The instructable describes well how to setup a permanent local IP for your phone

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