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Old 05-01-2017, 04:04 AM   #114 (permalink)
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Originally Posted by skybolt View Post
I have Vago's code running on an Arduino Pro Mini 3.3v 8MHz, (Amazon $10 for 3 of them) and it runs well. I also have it running on a TinyDuino, $20 but the size of a quarter. The hard part for anything nonstandard is you may need to make the car-to-arduino interface yourself. It's not hard, just follow the online schematics. You'll need a 7805 12-to-5 volt regulator, two 50k (or 47k or 51k) resistors (or 100k). Also, do NOT power the LCD from the 5V pin on the arduino, you will fry the on-board regulator. For the LCD I recommend the Adafruit button-and-LCD shield, then you only need 2 wires between the arduino and the LCD unit.

You will want to base your design on this schematic instead of the one you're suggesting, since the on-board voltage regulator -- well, I'll just say I've fried many, many arduinos by not using a beefy 7805 regulator. I'm still trying to get around it, and your mileage may vary.
Dear Skybolt, thank you for your reply. I forgot to mention that my MPGuino were using 7805 that you mention. I feel satisfied though when build my first MPGuino but cannot stand to build one more using that method. That's why i bought the Nano as i didn't have to wire all the component (atmega, crystal, caps, resistor, and so on). And you read my mine. I do want to use the 7805 for powering the arduino, and the LCD

Originally Posted by skybolt View Post
Remember: you can avoid the worst part of the wiring by using an LCD that already has it's own processing, such as the Adafruit one. (Check t-vagos code for all supported LCDs); as managing the wires between a small arduino and 12 pins of an LCD display is nasty. If you do go with the Adafruit LCD be sure to power it from the voltage regulator and not the arduino. Good luck!

The only reason I'm using the 3.3v 8MHz version is so that I can send serial output to a Pi, which will fry if it has 5v inbound on the receive pin, so you can certainly use the 5v arduino nano/pico/mini, etc. I suggest using a breadboard to get your car-to-arduino working before you solder.

As far as I can tell by reverse-engineering t-vago has a series of test mules, but not a particular PCB design. T-vagos stuff works very well on the Meelis hardware if you want a nice, tight package, and I believe it would be trivial to change out the LCD in Meelis' hardware from a 16x2 to a larger display (20x4?); I have given up on LCDs, but IIRC there are many adaptations already using 4-line displays, so I'd assume t's code supports it as well.
I do love the idea to bought MPGuino kit to save time, but if you've been to my country, our customs are really pain in the a**. For example, anything that have any price tag >$50 will be charged for an extra tax. And the process itself are wasting more time than to buy the component and assembling it

That's why i want to build MPGuino by myself again

At last, my Nano are arrived and just found out that my zener diode stock is run out. Must have 1-2 days more for the zener to arrive lol.
Many thanks for the reply i hope this build not gonna be as hard as the first one
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