Viewing 6 posts - 1 through 6 (of 6 total)
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  • #23766
    Leo
    Participant

    Dear friends,
    e’ I haven't visited the site for a long time, but I remembered you, now that I have a need.

    In fact my little problem is’ straddling the PIC forum and the THEREMINO forum.

    As you know the Theremino Master has 12 pin that can be set as you see fit by associating driving stepper motor functions to each pin, servo, ADC, PWM etc etc.
    The problem I have is’ I'm sorry “waste” three precious PINs to manage the colors of an RGB LED when one would be enough.
    I was thinking, as I can easily generate frequencies with THEREMINO AUTOMATION LANGUAGE, why’ do not make a circuit with a PIC that, receiving a fast frequency, sends its PWM to the three pins of the multicolor LED to generate the desired color.
    A bit’ like DTMF, the tone sent generates the color.
    What do you think?
    Greetings

    Leo

    #23835
    Picmicro675
    Moderator

    If you need to expand, you can opt for a system with a higher number of I / Os or you can connect it to the I2C BUS. For this BUS you need two specific pins and connect the so-called IOexpanders such as PCF8754 for eight bits or an MCP23016 to 16 bit.
    In another perspective, the SP interface could be used with a shift register such as 74xx595, which requires at least 3 feet, specific. Maybe you can work around the CS and use only two feet or even the method with a pin and eventual timing with capacitors.
    You could also take a look at the datasheets of the TCA5405 to understand how to use the one-wire implementation.
    Last but not least, charlie-plexing could be implemented, which with high output drives an LED (with grounded cathode) and with low output the other LED is driven (with positive anode). Obviously there are three RGB, then another pin should do double duty.
    In the Theremino system, I don't know how to act with its Firmware for these types of protocol.
    Finally, it must be taken into account that what is not in hardware must be implemented in software at the cost of more demanding execution times.

    #23857
    Leo
    Participant
    #23855
    Leo
    Participant

    Hi Picmicro675.

    the options you offer are obvious if you are in control of the PIC firmware.
    The THEREMINO system and in particular the Master, which uses a PIC 24, has a consolidated firmware for years and can no longer be touched.
    Therefore I can use the PWM functionality on pin.
    The idea of ​​DTMF seemed to me the best and I'm thinking of using the MT8870 chip,

    PCBA MT8870
    PCBA MT8870

    Here in Shenzhen, I found a supplier who sells it to me for a dollar.
    https://chinese.alibaba.com/product-detail/MT8870-DTMF-Voice-Decoder-Module-Telephone-60317881539.html
    Ciao
    Leo

    #23859
    Picmicro675
    Moderator

    Where are you? In China or the Gulf 😀
    But the DTMF, it takes 4 inputs. I didn't quite understand what project you have in mind. If we can help, you should also know what circuit you want to get. If you want to vary the three colors with a remote command, I might even think about using Bluetooth, that you will surely find a variety of Apps to install on Android and even Apple.
    Now I don't know how to use Theremino, I see it from the side of a microcontroller and write a program suitable for the need.

    #23861
    Leo
    Participant

    I have lived in Shenzhen for almost China 10 years.
    Probably and’ an explanation of the system I am building is necessary.

    I am using the THEREMINO system (www.theremino.com), which has nothing to do (at least in the beginning) with Arduino, if not the city of origin (Ivrea) and the ending.

    The system Theremino unlike Arduino has the firmware of the PIC24 locked, in the sense that it has not been updated and / or modified for several years. It is formidably stable and allows you to carry out projects quickly and easily. It has its own programming environment and a number of applications already’ ready.
    The system is based on the concept of slots and connects at high speed’ (no emulated serial port) con l’USB 2,
    The whole system e’ OPEN SOURCE.
    The Master has on board a PIC24 DIL from 28 PIN that leaves the user free 12 confiburable pins with internal idevice.
    Twelve pins can be many and few at the same time. So “waste” three precious pins to drive the switching on of three LEDs e’ Such a pity, therefore I am looking for a simple solution to have the three traffic light colors with only one pin.
    There would be the solution to use a 74xx138 in order to use the three pins as an input and have 8 output pin for which in addition to the three colors, I have others 4 output pin you can use.
    The management of the functions is done with a simplified programming language called THEREMINO AUTOMATION which you can find here:

    I hope I have cleared up some doubts.

    Greetings

    Leo

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