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Recent content by henninggs

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    Home automation: Human presence

    Hi I'm trying to build a smart house. To be smart, the house needs to know where people are located. Having all individuals to carry some sort of transmitter is not an option. I need the lights to turn on in the bedroom even if I'm wearing nothing but a towel. To detect human presence I think...
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    [SOLVED] Can a PIC be programmed over the SPI bus ?

    Your advice is more than enough. A google search for "PIC SPI Bootloader" uncovered among others this information:https://legacy.nrao.edu/alma/memos/html-memos/alma414/memo414.pdf Problem solved. The answer is: Yes, an established SPI bus will be sufficient. Thanks Abaz Regards Henning
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    [SOLVED] Can a PIC be programmed over the SPI bus ?

    Hi. I'm (trying) to design a CANbus node for my home automation project. Any given node consist of a main-board with a power supply circuit, a PIC18F26K80 and a demultiplexer to handle the chip select of up to 8 daughter boards. A daughter board will at have a (small) PIC running in SPI slave...
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    Creating a "Bus busy" signal.

    Thanks for all your replies. I have been reading up on the CAN bus and it seams that it better meets my needs. I think I'll give the CAN bus a try. Thanks.
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    Creating a "Bus busy" signal.

    Hi Alexandros. I do agree polling would be the standard way to go. The thing is I have to create a solution with very high focus on power efficiency. The network, when completed will have up to 200 nodes and it will be on 24/7. 90% of the nodes will just monitor some sensors and if the sensor...
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    Creating a "Bus busy" signal.

    It is a rs485 network. It is wired with cat5. Bus length max 100meters/300feet. 1 twisted pair for power, one for GND and one for rx/tx (The last pair is reserved) Nodes will primarily be monitoring temperature, humidity, smoke detector, PIR etc. in a building. I know I could implement...
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    Creating a "Bus busy" signal.

    Hi Let's say I have 10 nodes/microcontrollers on the same data bus. The nodes are powered by the same power line (Was thinking 24v). I was wondering if I could use this shared power line to send a signal when a node wants to use the data bus. I was thinking this: 1. When a node is turned on...
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    Adding a Master-Wake-Up signalto the rs-485 bus ?

    Would this work for signaling the master ?
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    [SOLVED] I need a a-fixed-value-device ?

    Thanks skogsjanne.
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    [SOLVED] I need a a-fixed-value-device ?

    Ah that's smart. What is a RC-link exactly ? (I assume it involves a Resistor and a Capacitate)
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    [SOLVED] I need a a-fixed-value-device ?

    I have 4 PCB's with a microcontroller on each. The boards are identically in both hardware and software. Now when powered on I would like MCU A to run subroutine A, MCU B to run subroutine B and so on. - so I need a way to tell each MCU what to run. This could be done with at dip switch and a...
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    Adding a Master-Wake-Up signalto the rs-485 bus ?

    It'll be a single-master system. Well, to save bandwidth and power. In a system where 99% of the traffic and a large part of the power consumption is "wasted" it just seamed a good idea. (Haven't done the math on the power consumption part, just guessing) That is a very good idea!
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    Adding a Master-Wake-Up signalto the rs-485 bus ?

    Adding a Master-Wake-Up signal to the rs-485 bus ? Hi. I have a rs-485 network with one master and multiple slaves. A slave is only speaking if spoken to by the master. Let's say I have a slave that monitors a sensor. If the sensor value gets outside a predefined range the master must be...
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    [SOLVED] Reading a dip switch using one pin ?

    Thank you cubanflyer, this is perfect.

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