Hello all, I am in my last semester of my computer engineering degree, and one of our last classes is a senior design project. My group is making a security door system using an HC12 Microcontroller, a solenoid, IR sensor, a "security" computer, and all that.
What I am here for is that I want to have it so that when the user enters a correct password, the MC can trigger a solenoid to lock/unlock a door. I was originally thinking of using just a sliding bolt lock to work best with the solenoids movements.
My main issue is that being a CE, my experience with circuits is limited, and our EE in our group is not... doing much on this, so since I actually want to graduate, I thought I would look into it myself. I found a couple of the parts I think I need. I found a possible solenoid:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=527-1028-ND
and I think this might work for a power supply:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=T969-P5P-ND
I talked to some of the instructors/lab people at school and they suggested I make a circuit that is basically the power running to, I think they said, a transistor. They said there was a transistor that would allow me to run the power to one connection, and a digital logic signal from my Microcontroller, and so when the MCU sends the signal to unlock the door, the power would pass through the transistor into the solenoid, and unlock said lock.
They also suggested picking up a diode, while on lunch today waiting for the food to be ready, I picked up a 12V, I think 600mA, something like that, Diode from Radioshack. It was a buck, if it doesnt work oh well.
They said this would prevent the sudden power jump when the solenoid activates from frying the transistor.
Ok now, if everything I have said so far is wrong, please give me some slack. I am basically doing all the microcontroller stuff, the EE stuff, and probably having to learn Python programming language, and I am pretty new to much of it.
What suggestions would you have for wiring this up? Know of a better power source? A better solenoid? What kind of transistor would I need to do what I want (Activate when the MCU signals it)? Diode advice?
Thanks in advance for your help on this, I want to make sure I do it right and don't destroy too many parts along the way.
Edit: I just looked at the power supply and the solenoid again, and unless I am doing the calculations wrong, it looks like the PSU only supplies 500mA at 12V and 6W, the solenoid says its 8W at 12V, which should be 666mA requirement right?
So those two will probably not like each other.
Edit2: Maybe this one?
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=EPS201-ND
What I am here for is that I want to have it so that when the user enters a correct password, the MC can trigger a solenoid to lock/unlock a door. I was originally thinking of using just a sliding bolt lock to work best with the solenoids movements.
My main issue is that being a CE, my experience with circuits is limited, and our EE in our group is not... doing much on this, so since I actually want to graduate, I thought I would look into it myself. I found a couple of the parts I think I need. I found a possible solenoid:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=527-1028-ND
and I think this might work for a power supply:
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=T969-P5P-ND
I talked to some of the instructors/lab people at school and they suggested I make a circuit that is basically the power running to, I think they said, a transistor. They said there was a transistor that would allow me to run the power to one connection, and a digital logic signal from my Microcontroller, and so when the MCU sends the signal to unlock the door, the power would pass through the transistor into the solenoid, and unlock said lock.
They also suggested picking up a diode, while on lunch today waiting for the food to be ready, I picked up a 12V, I think 600mA, something like that, Diode from Radioshack. It was a buck, if it doesnt work oh well.
They said this would prevent the sudden power jump when the solenoid activates from frying the transistor.
Ok now, if everything I have said so far is wrong, please give me some slack. I am basically doing all the microcontroller stuff, the EE stuff, and probably having to learn Python programming language, and I am pretty new to much of it.
What suggestions would you have for wiring this up? Know of a better power source? A better solenoid? What kind of transistor would I need to do what I want (Activate when the MCU signals it)? Diode advice?
Thanks in advance for your help on this, I want to make sure I do it right and don't destroy too many parts along the way.
Edit: I just looked at the power supply and the solenoid again, and unless I am doing the calculations wrong, it looks like the PSU only supplies 500mA at 12V and 6W, the solenoid says its 8W at 12V, which should be 666mA requirement right?
So those two will probably not like each other.
Edit2: Maybe this one?
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=EPS201-ND
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