rAtTrax or rAceTrax with MUI, SpinOFF All-in-one

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designer2k2
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Re: RaceTrax with MUI, SpinOFF All-in-one

Post by designer2k2 » Fri 9. Jan 2015, 07:01

D1-6 was intended as a debugging feature, but D4-6 is messing up the multiplexer, they draw too much current -> voltage drops -> bad signal.
You should only put D1-3 on it, they serve the purpose for debugging (if they are blinking, it should work :D )
https://code.google.com/p/multidisplay/wiki/BuildMD02

For the Layout, try putting the RJ45 jacks as close as possible to the edge, when you add the distance the case will take up it gets tricky to then reach for the little handle on the cables to release them.

Also the C10 is very close to the LM2907, making soldering tricky, i would suggest a clearance of 1x the pad size from the C10.

And one more, C1 for the 5V rail is connected over 2 vias and a bit of track lenght to the data RJ45 jack, maybe you can put it closer and with a direct connection.
The Intention for the C1 is to stabilize the 5V "far away" from the MD01 print, and it should do it as close as possible to the entry point on the MD02/03.
itsmyfault...

landracer
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Re: RaceTrax with MUI, SpinOFF All-in-one

Post by landracer » Fri 9. Jan 2015, 07:50

I do wish this damn program did have a better set of measurement tools. This is a joke...

So I changed those few little things. But I think I am going to move things around. I don't think this is close to final. Maybe you can give me your thoughts on mounting the CD74HCT4051 & LTC1050 on a separate board with breakout headers for my EGT's? example below
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Re: RaceTrax with MUI, SpinOFF All-in-one

Post by landracer » Fri 9. Jan 2015, 08:02

Definitely swapping places LED's/CAP ....

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Re: RaceTrax with MUI, SpinOFF All-in-one

Post by designer2k2 » Fri 9. Jan 2015, 17:34

Overall downside from this approach is that you need to carry the analog signal over the RJ45 connection into the ADW´s. I only move digital over the RJ45 line as there is no clear definition on how much resistance the connection points have.
Maybe choose a different connection method?

Think this could fetch some noise, but needs to be verified, best in a car with running engine (so that the ignition and injectors produce electrical noise)

You will also need to move the LM35 (T1?) on the breakout board, and as close as possible to the physical connection from the thermocouples to the PCB.
On the MD03 it is located just next to the headers.

Reason for this is the so called ice-point calibration. When the thermocouple wires hit the headers they form another thermocouple, and it is crucial to know exactly the temperature of this point.
Otherwise your reading will be off by exactly the temperature difference between the LM35 and the temperature from the connection point.

The LTC1050 is a delicate Amp, it makes x95 in one stage, and that with just some mV on the inputs (thermocouple voltage), i would put some good caps very close and ensure a solid ground layout is around, to get as little as possible surrounding noise into the signal.
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Re: RaceTrax with MUI, SpinOFF All-in-one

Post by bofh » Sat 10. Jan 2015, 01:16

ARM vs AVR8: yes, thats a stuff for another thread.

but let me say a few words to ARM-Boards: these ARM MCUs are a hell faster than the ATMega2560. but are they better suited for our application on the multidisplay pcb?

We want data acquisition at a constant frequency (for example 12Hz) and need also some advanced hardware features like input capture interrupts.
btw: Data acqusition at defined time intervals is a sort of real-time computing (RTC).
Its much easier to implement this on a dedicated mcu where I'm responsible (and in control) of the complete running firmware.

An ARM board (raspi, cubietruck etc) has a lot more computing power but it runs a full bloat operation system and is therefore not as predictable as the ATMega which is 100% under my control.
Imagine what happens under high system load on an operating system: maybe the linux kernel is busy with memory swapping and therefore the multidisplay process wouldnt get processor time even though it its needed at this point because we want to acquire our data at a constant rate.
Yes, there are some possibilities like RT-Linux to handle such realtime tasks. But it would be a hell more complex than running dedicated firmware on a simple MCU which is controlled 100% by our firmware.

In my opinion, the low-level data acquisition should always be done on a dedicated ATMega.

An ARM board could be an extension to the ATMega instead of a replacement.
btw: ARM extension is already in use: the android smartphone. it handles the visualization and data storage (mUI app). :)

If we're talking about an in-car graphical OLED / TFT display (i.e. dashboard) with expensive animations the mUI app could be moved from the smartphone to an in-car raspberry pi or similiar ARM board.

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Re: RaceTrax with MUI, SpinOFF All-in-one

Post by landracer » Thu 26. Feb 2015, 00:40

She is coming close to a completely embedded system. For some reason this atmega8u2 is not playing nice with my setup. More like doesn't work past taking code and pretending like it is going to work. Even registers as the MEGA2560 board. Then nothing. Regretting not using the FTDI chip now. Why? Because I can hookup and external serial to usb and boom works great! Go figure...

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Re: RaceTrax with MUI, SpinOFF All-in-one

Post by bofh » Sun 1. Mar 2015, 15:20

nice.
was it hard to solder the atmega 2560?

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Re: RaceTrax with MUI, SpinOFF All-in-one

Post by landracer » Mon 2. Mar 2015, 11:34

It's not really that bad. Just a quick drag solder. The first chip was a sacrifice from a Mega2560 board which had a flaky serial to usb. How ironic, the 8u2 being flaky..... So I de-soldered the 2560 off that board and zipped it on this new dev board. So far so good. I'm going threw LUFA, aka Dean Camera USB stack code as of now trying unsuccessfully to get this 8u2 to play nice... nevertheless, interesting experience. I'm am just short of asking Dean for his help, been playing with this for weeks now. Once this board is successfully built and working, I'd like to get you and Stephan each one of these boards for continued development free of charge. This way you guys have easy room for expansion. With all the current capabilities. This should fit ANY 2560 shield or homemade DEV board stack. :-) Love this project! :respect: Long live Multidisplay!

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Re: RaceTrax with MUI, SpinOFF All-in-one

Post by landracer » Tue 3. Mar 2015, 10:41

Well, It looks like the board works! :-) well, the basic parts that is.. Got the USB working, MEGA2560 runs great, SD logger is logging away, Bluetooth is forwarding data. I need to setup the ODBII connection part of the system and try that out.

The problem I seem to have now is bluetooth and the MUI Android app. I can connect with my Android, stream data to any Bluetooth terminal app ie; 'BT-simple-terminal'(any spp app seems to see data). But I cannot connect to the Bluetooth device threw the MUI app. I've tried on several devices now a Galaxy Note 8, a regular note 2, older G-Slate, and a t-mobile springboard . Any suggestions? I must be missing something simple here...

Exciting guys! Can't wait to get this project ready for some warm weather testing!! We'll be on the dyno here soon with PatriotLSR, I'd like to see if we can patch in with the project by then. :mrgreen:

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Re: RaceTrax with MUI, SpinOFF All-in-one

Post by bofh » Tue 3. Mar 2015, 21:54

:up: :respect:

the android app searches for an bluetooth spp device with the string "mdv2" in its name.
just add "mdv2" to the name of your bluebooth device (it must be paired with the android system!).

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