Practical Usage

Author: rt

  • VC-1: New circuit

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    The first circuit design for the VC-1 was a bit unstable and very dependant on the quality of the control signal. Since the goal here is to control the resistance with a PWM signal from the micro-controller, the control signal is going to be a fixed frequency square wave with a variable duty cycle (variable…

  • Tech Preview: Alesis Vortex (updated)

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    Update 16/1/31: The Alesis Vortex has been replaced by the Alesis Vortex Wireless . But the links below about in-depth reviews and complete user manual are still applicable and current. Update: 2012/12/21 – I am reviewing the Vortex in new posts. The first part is at: https://practicalusage.com/?p=781 Update: 2012/12/29 – Second part of the Vortex Review/Guide. Programming…

  • EM-1: Energy Monitor – Completed Hardware

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    Christmas vacations are for having fun. I did have fun! I completed a project that had been sitting idle for some time: The Energy Monitor for the house/office. The project is described over a few other posts. Most of the theory and practical application is explained in detail at openenergymonitor.org. I adapted their circuits for…

  • VC-1: Volume Control Beta

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    The VC-1 is. On the left, the Silonex Audiohm opto-couplers (OC) with the electronic drivers. it has been described here. On the right, the line-buffer/impedance-controller described there. It works as expected, using two digital pins on the Arduino micro-controller to change the volume. Partial specifications I use 2.2 Mohm metal film resitors as a voltage…

  • VC-1: More impedance control

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    In the previous post, I described the circuit that I’m using to emulate a potentiometer using a couple of opto-isolator (or opto-couplers?). There is one small problem with the circuit: the input impedance has to be quite low. If you just plug a guitar in the circuit, which generally has a high impedance output, it…

  • VC-1: Digital/Midi Volume Control

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    A user asked if I could design an FCB1010/PU-2 volume control. I love challenges… It took me weeks to get one working properly. The are two main parts to this: the analog side and the digital side. The analog side A potentiometer will generally be connected between ground and signal as: In this case, the…

  • PU-2: SD card capacity

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    I have just written a new version of the software that is used to convert a .CSV file into a Sysex file that the PU-2 can process. This version uses the SD card. Preleminary tests show that 2000 midi commands require about 16KB of storage. So, my (very) old 16Meg SD card can store approximately…

  • SD Card reader: No Voltage required!

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    While testing a slight modification on the PU-2 prototype, I decided to test the current draw of the SD Card reader described in the previous post. I placed my multimeter in series with the 3.3 volt pin and measured 11 milli-Ampères. Even while reading data, the current draw was constant. I then decided to measure…

  • PU-2: Data on SD card

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    Just in time! I received the SD card readers the day that I had planned to ship the first PU-2 Beta. I re-opened the boxes and fitted the card reader in each prototype. This is the SD card reader that I chose: It’s a generic card holder, that has the advantage of working with both…

  • FCB1010 vs PU-2: Why do it?

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    While waiting for parts (I do have to get a better inventory “system”) to complete the Betas for the PU-2, I went through a short period of discouragement. It’s hard to stay fully motivated when the project is bogged down by unforeseeable delays (or is it bad management?). But yesterday, I read an entry on…