Hey everyone. New to the forum if you could not tell.
I have minimal electronics knowledge.
I understand DC basics and what most components do.
What I am trying to attempt is an automotive application to run a motor.
Motor specs at 12v DC Under normal use will draw 6-7 amps.
I am attempting to use an input voltage from .1v ~ 4.6v DC to control the motor speed.
Technically the preferred peak for 12v output would be 2.3v+ into the circuit and 3v out from .2v in signal, Building a table from those two ends increasing voltage output as the input raises.
Using the Arduino Uno (Unless you have another recomendation.)
I found this page online and the potentiometer in theory would be my input signal.
On the other hand the transistor TIP122 does not have enough to handle the amperage when applying the ground.
Additionally being connected to a 12vt switched circuit in a car I would need to convert the 12vt to 5vt and regulate it?
Input Voltage (recommended) 7-12V???
I am clicking and reading around various sites including the playground to learn the programming behind it to control the transistor to get the results I need.
LEDs may or may not be used.
Input is greatly appreciated
You need to post a schematic.
Draw the circuit and post a photo of it.
Talking about your circuit without posting the schematic isn't going to help much because 50% of the newbies miswire their circuits.
If I were talking to an experienced tech and he told me he was using a TIP122 to drive a dc motor, am I going to ask him if he put a flyback diode on there to protect the transistor from back EMF ? Of course not. Am I going to ask him if he has the correct base resistor value ? Of course not. Am I going to ask him if he measured the current ? Of course not. If he said he had a handful (or bunch) of TIP122 transistors available and he was using them to drive a motor that draws 8 to 10A am I going to ask him if he trying to do it with a single transistor or am I going to assume he has four or five of them in parallel for a total of 20A current capability so that none of them are drawing more than half of the their rated current ? Of course not. So you see, the fact that you didn't post a schematic, (which is the first thing you need to do before you even start talking about your hardware problem) and the fact that you didn't mention any thing about the measured current (you only talked about specs), and the fact that you said the TIP122 can't handle the current (at this point I would ask if you had more than one of them) all lead me to believe that no matter what you tell us, there is something you didn't tell us, and we can probably assume there is a better than 25% chance you either left something out of your circuit (like a base resistor or a flyback diode) or the circuit is miswired or there's no common ground with the motor power supply etc.
In your case you linked a schematic (with description in spanish nothing Google Translate couldn't handle) for a speed control that had a base resistor and flyback diode so we probably don't need to even talk about those.
You talked about some other stuff regarding what voltages you thought were necessary and having to regulate the 12V for the arduino.
(there are numerous simple solutions for this) but before we discuss how to control your motor we need to get your feedback on
the idea of using something already made and ready to use rather than building your own 10A speed control
(the pot needs to be replaced by an analog voltage generated using a digital pot or an analogWrite signal with an RC low pass filter.
I would just buy an MCP4725 DAC since they'r so cheap
That takes care of your analog control voltage.
Here's a fancier one that takes a PWM signal in.
Thank you for the reply.
I can not replace the pot because the resistor is actually a thermal coolant sensor.
I am looking at that first ebay link you put up as well. it appears to possibly work My concern is I am controlling a coolant pump based off a precise voltage value from a coolant sensor so the calculations need to be precise. Normal operating temp is around 2.5v INput which result in a 6V OUT to the pump working at 1/2 efficiency.
I am trying to put together a circuit see attached image below.
The Capacitor, Diode and resistor on the PIN3 output I am not sure are the correct values.
Additionally I was directed to a IRF630NS Rectifier which may be capable of handling the current.
The schematic you posted doesn’t show any Motor power supply or connection point for the power supply. It should be shown at the (+) terminal of the motor . Also the entire circuit should be rotated CW 90 degrees to conform to standard schematic format.
Turn the entire drawing CW 90 degrees and redraw the labels so they are right side up with the new orientation. As shown it looks wierd and screams “No experience drawing schematics !”