Hi
I am new here and tried to find a similar project with the same problem as mine, but I am afraid I can't find anything anywhere (on the internet), because it's probably a pretty newbie and specific question. So I hope I could find some help.
I have to develop and build a constant current stimulator. The current has to be a squarewave between 0.0 mA and 50.0 mA. It has to start with 0.0mA when a button is pushed and it has to go up in steps of 0.1 mA with 1.0 mA/s. The squarewave has to be 100 Hz with a duty cycle of 2%, one pulse should be 0.2ms. The resistance of the stimulant will be variable between 30kΩ and 150kΩ, it can differ a lot, but will remain relatively stable during the stimulance.
The goal is to measure with how many mA different people start feeling a stimulance (they have to push the button again or stop pushing the button and the stimulance should stop and a small LCD screen should show how much the max applied mA was.
(eventually the duty cycle and mA/s should be able to be editted for different protocols, but that is future work, first I have some basic problems because of a lack of knowledge)
After talking with some people I decided/thought it would be the best idea to do this with a microcontroller. There are a few questions I still have.
1. Can I get 50mA out of a microcontroller?
2. How do I do it?
Next to this I am already searching for the best suitable microcontroller for the job. I have been doing a lot of reading how to chose the best microcontroller for the job and have made some decisions, but also a few I can't really decide upon yet.
Peripherals:
USB: (Protocols have to be setup (different duty cycle mA/s and some other stuff) by using a program on the pc
PWM controller: for setting the duty cycle?
POT: for measuring the resistance?
Timer dunno if this one is really neccesary yet
prefer a (0.1in)DIP package
CISC or RISC?: RISC is easier I guess
Architecture: Harvard or Von Neuman or Accumulator based (I don't really mind at this point as long as there is a small amount of ROM for setting up protocols)
(offcourse in need of EEPROM and maybe RAM)
clockspeed and busspeed needed I don't know yet?
8bit 16bit or 32 bit I don't know yet?
I would prefer to be able to program in something like C or java
(I was thinking about something from AVR btw)
In conclusion I still don't know a lot, but my questions are:
1. Can I get 50mA out of a microcontroller?
2. How do I do it?
I am new here and tried to find a similar project with the same problem as mine, but I am afraid I can't find anything anywhere (on the internet), because it's probably a pretty newbie and specific question. So I hope I could find some help.
I have to develop and build a constant current stimulator. The current has to be a squarewave between 0.0 mA and 50.0 mA. It has to start with 0.0mA when a button is pushed and it has to go up in steps of 0.1 mA with 1.0 mA/s. The squarewave has to be 100 Hz with a duty cycle of 2%, one pulse should be 0.2ms. The resistance of the stimulant will be variable between 30kΩ and 150kΩ, it can differ a lot, but will remain relatively stable during the stimulance.
The goal is to measure with how many mA different people start feeling a stimulance (they have to push the button again or stop pushing the button and the stimulance should stop and a small LCD screen should show how much the max applied mA was.
(eventually the duty cycle and mA/s should be able to be editted for different protocols, but that is future work, first I have some basic problems because of a lack of knowledge)
After talking with some people I decided/thought it would be the best idea to do this with a microcontroller. There are a few questions I still have.
1. Can I get 50mA out of a microcontroller?
2. How do I do it?
Next to this I am already searching for the best suitable microcontroller for the job. I have been doing a lot of reading how to chose the best microcontroller for the job and have made some decisions, but also a few I can't really decide upon yet.
Peripherals:
USB: (Protocols have to be setup (different duty cycle mA/s and some other stuff) by using a program on the pc
PWM controller: for setting the duty cycle?
POT: for measuring the resistance?
Timer dunno if this one is really neccesary yet
prefer a (0.1in)DIP package
CISC or RISC?: RISC is easier I guess
Architecture: Harvard or Von Neuman or Accumulator based (I don't really mind at this point as long as there is a small amount of ROM for setting up protocols)
(offcourse in need of EEPROM and maybe RAM)
clockspeed and busspeed needed I don't know yet?
8bit 16bit or 32 bit I don't know yet?
I would prefer to be able to program in something like C or java
(I was thinking about something from AVR btw)
In conclusion I still don't know a lot, but my questions are:
1. Can I get 50mA out of a microcontroller?
2. How do I do it?