Homebrew Multimode Digital Voice Modem adapter

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Florian Wolters made his own version of MMDVM adapter:

During experiments with digital voice mode in hamradio I discovered a nice project describing an adapter for D-Star, DMR and other digital modes based on an Arduino Due and a little PCB to be put on top. This unit is called the Multimode Digital Voice Modem or MMDVM (see [1]). It seems that this is getting quite popular because hard- and software is Open Source.

Homebrew Multimode Digital Voice Modem adapter – [Link]

Not a battery or a supercap, but a ‘thin laminate energy device’

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Murata’s UMAL is a low-profile high capacity energy device. Designed to meet the demand for a slim high capacity energy source with a maintenance-free extended life cycle in wireless sensor nodes, the UMAL has charge/discharge and life-cycle characteristics superior to conventional secondary batteries. By Graham Prophet

The UMAL has a nominal voltage of 2.3 VDC, can supply 12 mAh with a maximum discharge current of 120 mA and is able to withstand load fluctuations. It has a low internal resistance of 200 mOhm and can operate over the temperature range of – 20C to + 70C.

Not a battery or a supercap, but a ‘thin laminate energy device’ – [Link]

Accurately simulate an LED

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Jon Roman and Donald Schelle have a design idea on how to simulate a high power led to test your driver circuit.

Testing the driver circuit using LEDs, although easy, yields only typical results because the tests don’t factor in worst-case LED parameters and often generate undesirable light and heat during driver debugging. Although using a constant resistance might seem to be an appropriate approach, a resistor approximates an LED load at only one point on the current/voltage curve. An electronic load may prove to be a more useful approach. The control loops of the driver circuit and the electronic load, however, often result in system instability and oscillations.

Accurately simulate an LED – [Link]

Adjustable HV Power Supply for Stompbox

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This SMPS can be powered with low input voltage, from 5 VDC to 15 VDC and provided adjustable Output Voltage: + 92 Vdc to +340 Vdc.

Can be used too, as power supply, for the Xenon Lamp, Nixie tube Clock, VFD display, Magic Eye, Neon, and too many others electronics circuits who need HV power supply to work. Is great to use with many models of Nixie tube. It can drive 6 Nixie tubes, in multiplex mode, from 180 to 200V. Powered with low voltage from 5VDC to 15 VDC. With this SMPS you can power 250V @ current of 7.5mA! *In all case above, important note, DC and AC filters must be improved, if is desired reducing present HF frequency noises at output! Another fact, informed before, the RF energy is irradiated as magnetic and electric field, shielded assembly could be necessary!

Adjustable HV Power Supply for Stompbox – [Link]

Send and Receive SMS with GSM SIM900 Arduino Shield

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In this Instructable, you will learn how easy it is to send and receive SMS messages over GSM with Arduino.

One of the essential elements of building IoT project is the ability to connect devices. Wi-Fi and Bluetooth are good low cost choices, but they work only at close ranges, or in hotspot areas. When the device needs to be at a remote location GSM is a good and easy to setup option.

Send and Receive SMS with GSM SIM900 Arduino Shield – [Link]

How to Interface Stepper Motor With Arduino

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This tutorial is going to teach you some basics on using Stepper Motor while interfacing with Arduino and Stepper Motor Driver.

Bipolar Stepper Motor is DC motor that move in discrete steps. It has multiple coils that are organized in groups called “phases”. By energizing each phase in sequence, the motor will rotate, a step at a time. In order to be able to move the motor, you will need a motor driver. Thus, stepper motor driver A4988 is designed to play this role. A4988 stepper motor driver comes with heat sink. This stepper motor driver lets you control one bipolar stepper motor at up to 2 A output current per coil.

How to Interface Stepper Motor With Arduino – [Link]

ESP8266 temperature logger

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A ESP8266 temperature logger project from Facelesstech:

I decided to use the esp-01 module because I only need 2 GPIO pins since I was using the DS18B20 temp sensor and the WS2812 LED. This made the hardware really cheap and easy to reproduce too. I normally use FTDI boards when it comes to the USB to serial on my projects but I couldn’t find a FTDI board with micro USB that didn’t cost the earth. That’s why I went with the CP2102 which I hadn’t used before.
I think what really made me feel good about this project was the fact that I came up with the idea to use a Full sided male USB port for power teamed with a AMS1117 3.3v voltage regulator. This would allow me to just plug this straight into a USB wall wart or a phone charger battery bank.

ESP8266 temperature logger – [Link]

Iterated-map circuit creates chaos

DI5518f1Lars Keuninckx @ edn.com writes:

The Design Idea circuit shown below is a simple implementation of an iterated unimodal map, reminiscent of the logistic or Verhulst map encountered in the study of nonlinear dynamics. It is useful to show chaotic discrete-time dynamics to students, or as a random number generator. Specifically, the circuit implements: Vk+1 = rF(Vk), where F is a nonlinear unimodal function (a “bump”), implemented by the circuit in the dashed box. The response of this circuit is shown in the Vout vs. Vin plot.

Iterated-map circuit creates chaos – [Link]

Make Your Own Smartwatch From An Old Cell Phone

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Have an old cell phone laying around? Don’t know what to do with it? What if I told you that you could turn that old cell phone into a smartwatch!

What I’d like to do for this crazy/ambitions project is turn an old cell phone into a smartwatch. So obviously an old cell phone is required. The primary reason for this project is simply that I had an old cell phone laying around and wanted to find a creative way to repurpose it. The one I had is a Nokia 1100, but most other old cell phones would work, so long as you can find the schematics for the LCD online

Make Your Own Smartwatch From An Old Cell Phone – [Link]

RELATED POSTS

New PIC32MM family consumes as little as 500 nA

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by Clemens Valens @ elektormagazine.com:

The new PIC32MM family, currently Microchip’s lowest power 32-bit PIC32 family, features sleep modes down to as little as 500 nA. Filling the gap between the PIC24F XLP and PIC32MX families, the new family also offers so-called core independent peripherals that once initialized can function without intervention of or loading the MCU core.

New PIC32MM consumes as little as 500 nA – [Link]