Dhananjay Gadre & Nidhi Sharma writes:
Microcontrollers, the heart of all modern electronic gadgets, are increasingly powered with sub-5V power supplies. This complicates the control of external loads powered by higher voltages. The reduced I/O supply voltage leads to increased complexity in handling high-side voltage switching. Figure 1 illustrates the conventional solution for controlling a 5V high-side switch, driven here by a 3.3V signal.
Zener level-shifter drives high-side switch - [Link]
by brmarcum @ instructables.com:
I hate Christmas tree lights.
Well not really, I just don’t enjoy having to climb under the tree every time I want to plug in or unplug the lights. In the interest of saving my sanity, I decided to build a motion activated switch that can power the lights for me. It has an integrated adjustable timer so they will stay on for as long or as short as I want. Here’s a video showing the final test on the fish tank light.
Motion Activated AC Switch - [Link]
App note from International Rectifier on their IR331x part which offers a bunch of power protection and control all in one chip. [via]
The new IR331x devices designed in P3 technology provide more accuracy of the current feedback. The IR331X devices suit for any application where the load current sensing is required. IR331X is fully protected: programmable current shutdown, over temperature shutdown and reverse battery protection. The current sensing features offer current readout accuracy, high frequency bandwidth, a versatile way to control the current shutdown and replaces the shunt resistor.
App note: Current sensing high side switch - [Link]
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]
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]
by Viktor Safronov:
Sometimes you may need a group of switches where, if any switch is activated, it deactivates the previously active switch. This Design Idea implements such a function with relays.
This “one and only one” function is often implemented as mechanical switches in which an actuator (usually a movable metal bracket) is used to switch contact groups on and off. When any switch is pressed, this bracket first deactivates all switches, then activates the pressed switch.
Exclusively select 1 of N relays - [Link]
The era of the MEMS switch may finally be here thanks to the research efforts of GE. Its MEMS chip, as small as 50 microns square, swathes as fast as 3 GHz and can handle up to 5-kiloWatts of power, making it a candidate for everything from industrial power control, to turning on light bulbs to switching antennas inside a smartphone.
MEMS Switch from GE claims fastest/highest Power Crown - [Link]
Do you have an application where a black switch is not suitable? We have an elegant white one for you.
Rocker switches are available in a vast majority in a black version. When we take a look at catalogues of renowned producers we´ll usually find there mainly black types and only a few white ones. However a switch in a black version can be advantageous in many applications like office devices, PC, “white” (home) goods, lighting, equipment, but also in many other devices having enclosure other than black, or where just a white version can be an interesting design element. Even in our electronic branch it´s particularly true, that a “package sells” and an aesthetic design of a device can be one of the factors of a market success.That´s why you can find in our stock two novelties – a white rocker switch 1832.3311 ((DPST, 20A/250VAC) as well as a round 1881.1105 (SPST, 12A/250VAC). Both novelties belong to well proven series with widely known properties. Detailed description can be found in 1830 and 1881 series datasheets.
Recently we added into our standard stock offer also many other types from Marquardt and you can find them below this article.
Black or white? - [Link]
vpapanik demonstrates the EM-1712 magnetic on-off switch on the breadboard:
Ultra-low standby current (less than 0.1 mA) magnetic on-off switch based on the AKM micropower hall bipolar latch EM-1712 and Microchip MCP1801 3.3V LDO. Of course, any regulator with EN (or SHDN) pin can be used. Ideal for touchless power switching, e.g. battery operated devices in watertight enclosures.
Micropower magnetic on-off switch - [Link]
The Ethos lite is a tiny unmanaged Ethernet switch that has 5 ports, supports 10/100mb data rates on a board measuring just 1.75″ x 1.75″ and weighing only 15 grams. One primary area where the Ethos lite stands out is in situations where weight and power are high priorities such as Unmanned Aerial Vehicles or robotics. All 5 ports are fully shielded with magnetic couplers for common mode rejection meeting Ethernet wiring specifications. This allows designers the ability to skip the large RJ45 connectors and wire directly onto connected peripherals or place the connectors in a more flexible location.
The Ethos board can accept a wide range of voltage input from 5-15V making it an ideal fit for Unmanned Systems that provide battery power. The Ethos board can also double as a 3.3V regulator providing up to 1 Amp of current. Under full load (all 5 ports actively sending data) the Ethos consumes less than 2 Watts.
Connections to the Ethos lite are provided by Molex PicoBlade headers with one for each port and an additional connector for power. As an added feature the MDIO lines to the Ethernet switch IC have been exported allowing developers access to management data registers.
Included with the Ethos lite is the main board along with 6 Molex PicoBlade cables (5 with RJ45 connectors, 1 with bare wires for power). The Ethos lite costs $250 with the ability to purchase extra Molex cables in a variety of configurations.
Gadgetsmyth releases the Ethos lite – A tiny Ethernet Switch – [Link]