nevdull @ instructables.com writes:
Tactile switches (a specific type of momentary switch) are everywhere and they are especially popular on DIY electronics and microcontroller boards because they are well suited to act as a boot option or reset switch. Particularly, momentary switches are switches that don’t save their state when you depress the switch. That is, when you push the switch (and while you have the switch depressed) the circuit is ON, but once you let off the switch it reverts back to OFF.
Use a Momentary or Tactile Switch as a Pushbutton Switch - [Link]
With Texas Instruments’ WEBENCH Schematic Editor, engineers can customize power-management designs and simulate the circuit created within the WEBENCH environment. According to the company, the new feature reduces design and verification time from hours to minutes. The editing and simulation package maintains a library of over 40,000 components. As a result, it’s possible to incorporate multiple mixed output capacitors, filtering, board parasitics, and snubber circuits into WEBENCH power-supply designs. Then those customized power designs can be simulated (using the WEBENCH Power Designer’s Spice simulator) before they’re exported to CAD development platforms like Cadence OrCAD Capture CIS, Mentor Graphics Xpedition xDX Designer, CADSoft EAGLE, and Altium formats (e.g., Altium Designer). The WEBENCH environment consists of online tools such as Designer and Architect that enable end-to-end analog circuit design.
Customize Power-Management Designs With Editing/Simulation Environment - [Link]
Acidbourbon posted a step by step guide of his digitally controlled HIFI amp with 4 way mixer build:
The amplifier section is trivial. You just buy a TDA1554Q, bolt it to the inside of an aluminum box, solder some resistors and capacities to the pins of the IC according to the application note in the datasheet and you have a small HiFi amplifier.
Because the volume control has to be digital, I’m using digital potentiometers. Sadly there are no (affordable) logarithmic digipots available. However I found this method which employs a linear potentiometer in combination with a fixed resistor to “fake” a logarithmic potentiometer.
Digitally controlled HIFI amp with 4 way mixer - [Link]
by Claude Haridge:
Microcontroller-based products sometimes require rotary switches. As many microcontrollers have an onboard ADC, it is easy to replace the rotary switch with a low cost potentiometer, when a rotary switch is too expensive or unavailable.
Although digitizing a potentiometer setting to act like a switch requires only a few instructions, an immediate problem is that instabilities in value occur at the switching threshold between one value and the next due to electrical or mechanical noise. The solution is to introduce upper and lower hysteresis thresholds about each transition so that the potentiometer needs to move beyond a threshold before another switch state is validated. For every updated switch state, another pair of thresholds replaces the previous. In this manner, the hysteresis provides clean switching between states.
Replace a rotary switch with a potentiometer - [Link]
Nabil Tewolde build a bluetooth OBD-II adapter. He writes:
The board is basically the reference schematic for the STN1110, which converts many OBD-II physical layers into RS232. The bottom of the board has a bluetooth module from Deal Extreme. The plan is to connect a smartphone or tablet to the device and log data.
Bluetooth OBD-II Adapter - [Link]
New GSM/GPRS/GPS/GNSS modules Quectel offer also special functions, able to make your product exquisite.
Development in the field of communication modules is fast and there are still more segments for their applications. That´s why company Quectel always comes with novelties or at least with enhanced versions of existing modules. This is also the case of two novelties M95EB and UC15.
Module M95 is certainly familiar to you from several our articles like for example Even the Vodafone confirmed quality and reliability of Quectel M95 GSM module. M95 belongs to a TOP in the segment and recently we announced you an eCall support. Meanwhile, this version came to a mass production and we can easily differentiate it by the „EB“ suffix. New version M95EB also supports Dual SIM function (DSSS), what makes it extra reliable even for emergency systems and similar applications. A previous M95 as well as new M95EB are compatible and they will be on the market in parallel, that´s why company Quectel recommends to use the new version (EB) only for applications where you plan to use these new functions.The second novelty is the UC15 module (UMTS/ HSDPA), which is similar to UC15 in many respects, but it´s smaller (29x29x2.5mm) and it has only 66 pins. The main difference is that UC15 doesn´t support GPS/ GNSS and it´s also somewhat slower (upload). UC15 is cheaper than UC20 and in many applications it can represent a very interesting alternative for a very attractive price.
A comprehensive description and comparison of Quectel modules can be found in the Quectel brochure as well as in the datasheets in particular types.
With modules Quectel UC15 and M95EB you’ ll gain Dual SIM, eCall, HSDPA and other functions - [Link]
High-performance Easy-to-use Mini Power Modules for Makers. Innovative circuitry enables positive/negative supply in one module.
PNMini is a family of high performance, easy-to-use DC/DC Power Modules for DIY electronics.
PNMini can be used as positive supply or negative supply. If both positive and negative supply rail are needed, just connect two PNMini modules together. No hardware changes are required.
PNMini is available in a small PCB package that enhances thermal performance and allows for hand soldering or plugin use. It provides +3.3V/-3.3V, +5V/-5V, or +12V/-12V output directly to your circuits requiring no external components.
PNMini – Positive/Negative Power Supply Module for Makers - [Link]
A beginner’s guide to AVR programming on instructables. It cover the basic setup to light up some leds.
Beginner’s Guide – AVR Programming - [Link]
Build this homemade “one-size-fits-most” speed controller for use with your hobby projects. It’s small, it’s flexible, and it’s built with off-the-shelf components around the venerable 555 timer IC.
Dial-a-Speed Motor Controller - [Link]