Hello everybody!
I just want some advice about my project. I'm a beginner in electronics, programming and also arduino.
It's a dashboard of a Baja (off-road car) with an arduino UNO and three Hall effect sensors to measure speed, rpm and fuel level. It has two 7 segments displays to indicate the speed, six leds to indicate rpm and four leds to indicate fuel level.
I found an IC MAX7219 to bind all these leds and i'm having some doubts to project it.
I want to know if it is correct and if it needs some additional components. Regarding the programming, i want to know if there is an easier way to project it.
Considering "I'm a beginner in electronics, programming and also arduino"
then I can only say Wow, thats a big chunk in one go.
Try something simpler to begin with or at least break it down into individual projects as a starter.
Hi, check what the output signal is from the three Hall Effect Sensors.
The analog inputs of the arduino is only 0 to 5Vdc, any higher will damage the input.
Also make sure all gnd connections between your sensors and the controller are good and you have a well filtered and bypassed 5V power supply for the controller.
A 0.1uF capacitor across the supply pins of the controller is also essential.
I notice you have not crystal connected?
The diagram you posted is missing definition, cannot read most of the text.
bluejets Thank you! This project is for a competition between universities and i'm the only one in charge to project the dashboard for my university. There's nobody interested in. I must do it!
Tom I have no words to describe how happy i was at the moment that i saw your post. Thank you for all the advices! I'll be careful about the sensors. I'm going to use the arduino UNO, not only the microcontroller, should i still put the crystal?
Hi! I finished the design. I put the CAD package for UNO, i added a voltage regulator(12V to 5V) with capacitors and a voltage divider with a led to indicate when the battery is low. About the sensors i'll do just like this image >
Is it all right?
Now i'm trying to test it without the sensors and then with them. I know that MAX7219 has a library called LedControl, but i'm a beginner with programming as i said. I'll try to do it and then i come back with my doubts.
Little not to the wise: Atmel has a disclaimer that there products can't be used in an automation or avionic device due to "We're gonna sue you if your device fails in our car".
And only 2 segmented displays? From what i know a baja car can go allot faster than 99mph/99kmh...
Adding another display only takes you 1 output in that configuration. And unless you plan to use the millennium Falcon it's enough.
WalysonMachado:
Hi! I finished the design. I put the CAD package for UNO, i added a voltage regulator(12V to 5V) with capacitors and a voltage divider with a led to indicate when the battery is low. About the sensors i'll do just like this image >
Is it all right?
Now i'm trying to test it without the sensors and then with them. I know that MAX7219 has a library called LedControl, but i'm a beginner with programming as i said. I'll try to do it and then i come back with my doubts.
Not sure if you are aware that the device you show is a latching hall switch. i.e. it turns on with a south magnet and will not turn off again until it comes under the influence of a north magnet.
Also if you download the data sheet for it you will see recommended circuit additions to minimise noise etc. which you will more than likely encounter and wonder why it refuses to work the way you want.
With the correct hall switch, measuring rpm and speed it is just like a switch, so use as a pulse.
With the fuel level, I think maybe a different sensor(analog) unless you want several points of level.
I'm little bit confused about the Hall-effect sensor. I don't know which one i choose to measure the rpm and speed and which one i choose to measure fuel level.
I heard about the A1321 Allegro sensor to measure fuel level outside and under the tank with a magnet buoy inside the gas tank.
I thought that i could use the US1881 to measure the rpm and speed with a magnet passing through it, and as it pass i could count.
Does anyone know which Hall-effect sensors should i use for both applications?
