0
\$\begingroup\$

I want to start a 9v DC motor in one direction for 5 seconds after 30 minutes delay, then turn it off and then after 30 minutes, restart it for 5 seconds in reverse direction and then stop it. The same process should continue in cycle. I already have a 30 minutes timer circuit which can turn on the motor after 30minutes. I need this circuit for a Hatchery, the motor will be used to turn eggs on another side after each 30 minutes. What I want to ask is that can I make a circuit with these functions without using micro-controllers?

Please guide me so that I can proceed in the proper direction.

\$\endgroup\$
  • 2
    \$\begingroup\$ What type of motor are you using? Is it an AC or DC motor? Is it servo? Is it stepper? Is it going to stop or pause after restarting for 5 seconds in reverse direction or directly start for 5 seconds in normal direction? \$\endgroup\$ – abdullah kahraman Dec 13 '11 at 7:53
  • \$\begingroup\$ @abdullahkahraman I am using a simple 9v Dc motor. It has to stop/pause after 5 sec rotation. After 30min it will rotate One time in normal direction then stop and then after 30 min it will rotate in reverse direction for 5 sec and then stop. The same process will continue in cycle. \$\endgroup\$ – Naeem Ul Wahhab Dec 13 '11 at 11:34
  • \$\begingroup\$ Running a motor for a fixed time is generally a poor way to do positioning, unless you know that it's okay to run it too long with it stalled part of the time. Usually a positioning application uses a limit switch or sensor. You can build such a limit mechanism into a software-, electronic-, or relay- based control system. \$\endgroup\$ – Chris Stratton Dec 13 '11 at 19:02
  • \$\begingroup\$ I know this is sort of old-school, but white goods like washing machines and the like often had rotary encoders that would be the programming for the various modes supported. Some relatively simple industrial controllers also used such mechanisms. If all we need is the simplest "do this, wait, do other, wait, repeat" then it might be apropos. \$\endgroup\$ – user65586 Mar 21 '16 at 20:36
3
\$\begingroup\$

Since this is for a real world application, not a hobby project or a school assignment, the requirement not to use a microcontroller is just silly.

A micro is the obvious and easy way to do this. A very small micro like a PIC 10F200 could do this, but since this is also apparently a one-off there is no need to economize. Something like a PIC 18F2520 would be easy. That's way overkill, but the extra $3 or so will be made up with easier programming. This part has a internal RC oscillator, so you pretty much feed it power with bypass caps and it can run.

I agree with Wouter in that relays are appropriate for this since it's a one-off and you are switching very slowly. One DPDT relay is used to set the polarity, and a second SPST is the on/off switch. Now you only need circuits to drive the relay coils from two digital output lines from the micro.

\$\endgroup\$
  • \$\begingroup\$ While people who have used them see micros as an easy and extremely cost effective solution they can be a bit intimidating to those used to thinking more in terms of electro-mechanical solutions rather than software. Even something intended to make it really simple such as an arduino can sometimes involve a lot of work getting a development PC set up and communicating with the board. \$\endgroup\$ – Chris Stratton Dec 13 '11 at 17:54
  • \$\begingroup\$ @Chris: Microcontrollers are a integral part of electronics. They must be learned and understood just like resistors, capacitors, and transistors. Show me how to design a audio amplifier without those confusing capacitors is not a valid question. \$\endgroup\$ – Olin Lathrop Dec 13 '11 at 18:15
  • \$\begingroup\$ invalid comparison - people were solving such problems for decades before micro-controllers were invented. For someone where the learning-curve/benefit analysis points towards using them they tend to be a great solution, but if someone without that wants to solve a single problem, they are by no means the only acceptable answer. There's a big difference between "being an engineer" and "solving (one) engineering problem" \$\endgroup\$ – Chris Stratton Dec 13 '11 at 18:42
  • \$\begingroup\$ @Chris: You can probably build a house with only toothpicks, but other people will probably have as little patience with that silliness as this one. \$\endgroup\$ – Olin Lathrop Dec 13 '11 at 19:35
  • \$\begingroup\$ your repeated calling it "silly" ignores the key point that you are not the person who would have to make it work The poster's skillset is different from yours, and what is the right choice for you or I is not necessarily they right choice for this fish hatchery. Remember also that a microcontroller is going to require either a user interface or support equipment if the result is to be maintainable. A 555 seems comparably crude, but you can fully document everything needed to maintain, adjust, or reproduce it on the inside of the box cover. \$\endgroup\$ – Chris Stratton Dec 14 '11 at 1:14
4
\$\begingroup\$

Of course you can make this without a microcontroller, using radio tubes if it must be. (but it hurts my brains)

I think a CMOS 555 can make a 5 seconds once each 30 minutes pulse (check the datasheet), then use a divider to create the direction.

You did not provide details about the motor, so I can't advise on how to control it. You are switching direction very infrequently, so a relay would eb a simple solution. Maybe even use a second relay to switch the motor on or off.

\$\endgroup\$
  • 1
    \$\begingroup\$ @TheNoble-Coder There's more to a motor than its voltage. The current consumption is a big factor in switching component selection. \$\endgroup\$ – Majenko Dec 13 '11 at 15:42
  • \$\begingroup\$ Without using a micro controller you'll end up with a fairly complex circuit for a fairly simple function. Either way here's a few articles to get you started: doctronics.co.uk/4060.htm reuk.co.uk/Timer-Circuits-With-4060B.htm \$\endgroup\$ – snoopen Dec 13 '11 at 23:15
  • \$\begingroup\$ Thanks for the reply. Hmm keeping these answers in view, I think it's really going to be hard without a microcontroller. \$\endgroup\$ – Naeem Ul Wahhab Dec 14 '11 at 4:34
  • \$\begingroup\$ Its hard decision for me to accept any one of these answers. As all the answers are good. I would have voted for all if I could, as all the answers are good. \$\endgroup\$ – Naeem Ul Wahhab Dec 14 '11 at 4:45
  • \$\begingroup\$ @TheNoble-Coder - a micro-controller can be a good choice, and flexible in the extreme, but it's entirely possible to build a simple solution without toolchain costs or installation challenges using radio shack parts like the 555 and relays. They are also starting to carry arduino boards if you want to try a packaged micro-controller. It's really a matter of which tools/technology you would prefer to work with. \$\endgroup\$ – Chris Stratton Dec 14 '11 at 16:38
1
\$\begingroup\$

I am sharing the same idea as Wouter van Ooijen does, however I am guessing that things are going to get nasty with temperature and the tolerance of the resistors. You may have hard and long times calibrating the timer to your wishes( 5 sec and 30 min), it is not impossible to calculate the values though.

You can use 555 chip. PWM configuration seems usable. Below gives some idea on what PWM is and here is a great tutorial video on it.

PWM

Here is a site that describes the 555 chip in PWM mode and the circuit:

555 PWM Circuit

You can tune 1k resistors, potentiometer and the 0.01uF capacitor to your needs to create a 5 sec on 30 min off PWM. I think that is about 0.27% duty cycle :).

After that, you are going to connect its output to a T flip-flop. Every time the output of 555 goes high-to-low or low-to-high it will toggle the flip-flop's output meaning that a cycle of 5 sec and 30 min is complete.

Then you are going to design a control the logic to drive the H-Bridge. If the output of the T flip-flop AND the output of 555 chip is high, then turn the motor CW, if it is low AND the output of 555 chip is high, then turn the motor CCW.

\$\endgroup\$
  • \$\begingroup\$ Thanks for the reply. Hmm keeping these answers in view, I think it's really going to be hard without a microcontroller. \$\endgroup\$ – Naeem Ul Wahhab Dec 14 '11 at 4:33
  • \$\begingroup\$ Great idea, I will sure try it \$\endgroup\$ – Naeem Ul Wahhab Dec 14 '11 at 4:38
  • \$\begingroup\$ Its hard decision for me to accept any one of these answers. As all the answers are good. I would have voted for all if I could, as all the answers are good. \$\endgroup\$ – Naeem Ul Wahhab Dec 14 '11 at 4:45
0
\$\begingroup\$

To be as straight forward as possible: yes, you can make a circuit with this functions using a micro-controller. There are already more than a few versions, most of them using an H-bridge circuit (http://en.wikipedia.org/wiki/H_bridge)

This one is great: http://itp.nyu.edu/physcomp/Labs/DCMotorControl it's a very well organized tutorial and it shows you how to build the assembly from scratch.

Once you got the whole assembly up and running, "The Time library adds timekeeping functionality to Arduino with or without external timekeeping hardware" :) (http://www.arduino.cc/playground/Code/Time)

Of course if you don't like Arduino you can do this almost any kind of modern day controller, it's just that this, I believe - would be the fastest way to go (and also not too expensive)

I hope you find this useful,

Cheers, Dan

\$\endgroup\$
  • \$\begingroup\$ Well I think he is curious if this could be done without a micro-controller. \$\endgroup\$ – abdullah kahraman Dec 13 '11 at 18:10
  • \$\begingroup\$ Sorry, it seems I've misread... I'm pretty sure it is possible, but for what it's worth I think using a micro-controller would be a better approach since schematics are available, code is available and maybe the most important thing code is very configurable, say you would need 21 seconds of motor run and a 20 minutes delay, it's as easy as re-flashing, no need for any extra components. Sorry about that mistake again :) \$\endgroup\$ – Dan Dec 13 '11 at 19:33
  • \$\begingroup\$ It happens :) The most logical option is using a micro-controller to me, too. However, some guys don't just like it or want some other ways to control it. One has to have respect, I guess. \$\endgroup\$ – abdullah kahraman Dec 13 '11 at 19:47
  • \$\begingroup\$ Thanks for the reply. Hmm keeping these answers in view, I think it's really going to be hard without a microcontroller. \$\endgroup\$ – Naeem Ul Wahhab Dec 14 '11 at 4:33
  • \$\begingroup\$ Brother Dan, Don't be sorry :) I actually needed guidance to go for microcontroller or other methods. Your answer do have guided me. thanks for such a good answer. \$\endgroup\$ – Naeem Ul Wahhab Dec 14 '11 at 4:43

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.