19 in a box

Update ! PCB is finish for test !Software: Neopixel control was implemented ! (up to 8-RGB-LED's)

Update ! PCB is finish for test !

Software: Neopixel control was implemented ! (up to 8-RGB-LED's)

ELWMS 2.0, the multitool with new hardware and additional functions: - Buzzer was added for sound indication (High, low) - Higher output frequency up to 4 Mhz - USB-Uart (transmission of measurement data, firmware upload) - 3 push-buttons - Voltage measurement up to 15 VDC - Servo-Out (1-2ms signal to control servos, controlled by push-buttons) - Toggle-Out (High/Low controlled by push-buttons) - DCF 77 decoding - NMEA decoding And more could follow... -difference voltage measurement/hold function -neopixel controling -DS1820 temperature decoding if detected in 1-wire mode

Projektelemente

prototyp (JPG, 1.12 MB)

pcb board for this project (JPG, 878.96 KB)

pb ready for test (JPG, 653.79 KB)

elwms-2-0-v2-max382.jpg (JPG, 2.11 MB)

elwms_2_099c_de.zip (ZIP)

Diskussion (4 Kommentare)

tdsnet vor 9 Jahren

Hi, the schematic link is dead.

It's possible to reactivate?

Thanks a lot

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tuecok vor 9 Jahren

Hi, I think you should be logged in, than you get all needed files...

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1 Kommentar(e)

tdsnet vor 9 Jahren

Hi, the schematic link is dead.

It's possible to reactivate?

Thanks a lot

Antworten

0 Kommentar(e)

JohnHind vor 9 Jahren

As I commented on the earlier version, I'm still not getting the need for the analog switch between the probe and the MPU. I would simply connect the probe direct to all the MPU IO pins and make sure in firmware that a maximum of one of these pins was driving as an output at any time. The other pins should not be harmed (by any voltage between 0 and VCC) as long as they are configured as high impedence inputs.

Also the I do not quite get the circuitry around IC3 and IC4. Is this all about measuring up to 15v? Would it not be simpler to use a resistive divider to divide the input by 3 to keep the range within 0-5v?

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JohnHind vor 9 Jahren

Simply hard-wire the probe to all the pins you need. For input pins it will not matter - just ignore the inputs the selected function does not need. For output pins, re-configure them in firmware to be inputs when not in use and then ignore them. I am assuming here that all pins with specialist output functions are also capable of being reconfigured "on the fly" to be inputs. This is true of the PIC processors I am familiar with and I believe the Atmel ones are similar. These chips already have a multiplexer internally so it should not be necessary to provide one externally. As for input conditioning, you could avoid the need for the different voltage rails by using a resistive divider to bring the maximum voltage down to 5v and then a programmable or switchable gain op-amp to boost lower voltages back up to the right level. This has the extra advantage that it can accommodate voltages below 5v as well as above. Does not allow output voltages higher than 5v. of course. (Edit: If you were able to look at other microcontroller families, the circuit could be simplified further and made even more versatile. Chips with USB built in and with internal Programmable Gain Amplifiers are available as are chips with full pin multiplexers able to provide any analogue or digital function on any pin. The Cypress PSoC range comes to mind and there are also PIC chips with some of these functions.)

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tuecok vor 9 Jahren

Hi John, there is no pin which can drive every function,e.g. Timer-out, counter-in, analog-in. So there is a need to work with an multiplexer in my opinion. A resistive divider would avoid correct levels for many functions. I think that is the best solution to seperate every function to a special pin if needed, especially for future development it will be easier.

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2 Kommentar(e)

Frank Sauer vor 9 Jahren

I asked it in the morning at the first version of the project. But this second version is much more interesting. Is it possible to get a eagle or gerber file of the PCB?

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0 Kommentar(e)