Project using Sparkfun`s IOIO for Android ( ) where power consumption is a concern. The IOIO board provides the phone with 500 mA charging if I`m correct, which is too much for continuous operation. There`s a trick I have in mind where I want to power the phone and the IOIO board separately from the same external power source (Of
Click here to download the full size of the above Circuit.
course the phone gets its 3. 7v while the IOIO gets 5v). The catch here is that I want to cut off the 5v line on the cable from the IOIO to the phone, leaving the GND, Rx and Tx (Which are good enough for any serial transmission). USB doesn`t have the notion of TX and RX lines, it`s not a UART. The data lines are D+ and D- used for bidirectional differential signaling. The VBUS line (which you refer to as Vcc) is essential for detection the presence of the host (IOIO in this case), so what you`re suggesting will not work. The best you can do is use the current limiting trimmer that`s on the IOIO. Start with it fully clockwise, then, with the Android connected, turn it counter-clockwise until the connection drops, then back some. The minimum current that can be achieved like that varies by phone model. Also, turning the screen and comms off on the Android will reduce current significantly provided the phone battery is fully charged. @AhmedFarid Ytai`s answer is correct. The VBUS/VCC on the usb cable is required for the connection to work. The trimmer is the only way to change how much current draw is allowed. But the real question is, if you are powering both from the same external supply, why Are you regulating the 5v down to 3. 7v The phone would be more efficient at doing that itself from it`s normal 5v charging. Passerby May 29 `13 at 5:36 Never thought the creator himself would answer my question! I never noticed the...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This....
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound,....
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
characters left: