Circuit Lake

This electronic project used to remote control and power on/off the PC. The extended guide for the infrared receiver with hardware side function to remotely switch the PC on and off as full USB variant is now available and got the name “USB Ultra infrared receiver” or briefly “USB Ultra IR”.
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I think this is Cool idea related to Microcontroller project created by J. Lepot. This USB scope is based on a Atmel Tiny45 cpu and cost less than 5€ with a homemade pcb. It has 2 analog inputs and can supply 5V on the 4 pins header on the right. One of the inputs can be scaled down with the trim pot.

The firmware in the Tiny45 is written in C and compiled with Winavr and usb source code from obdev. (more…)

I want to build high quality preamplifier with built-in DAC from SPDIF or USB for my power amplifier Leachamp. I tried to design DAC from USB with this circuit on one-sided PCB and I was successful.

Schematics is from datasheet of PCM2902. Circuit includes DAC and ADC, SPDIF output and input and HID part with 3 buttons for MUTE, VOL+ and VOL-. I used only DAC part. Other parts are not used. For high quality playback is needed to use external low-drop voltage stabiliser for DAC part. I used LP2951CM which was available at local store. Output voltage is set to about 3.7V with two resistors. Circuit board is designed regarding to good ground placement and separating of analog and digital ground. These ground are connected in one point at USB connector.
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