Automatic Pill Dispenser

Hi,

I am new the website but I've taken a microprocessor class before and used the HC12 board so I know the basics of embedded design. For my senior project we are suppose to design a pill dispenser that receives schedule information from a website and dispenses the specific pill accordingly to the time of the schedule. Now I guess my question would be what kind of micro-controller would I need to put into the pill dispenser itself? It would have to connect to the internet using Ethernet, and receive the schedules and somehow control the dispenser unit to dispense the right pill at the right time. Also it would need to incorporate a variety of functions such as an audio alert and visual alert to tell the patient when to take the pills. And dispensing the pills it would need to send a signal to the motors of the dispenser unit. What do you guys think is the best microprocessor board to implement these features?

Thanks

Reply to
tlo57
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I'm tempted to say any micro with the features you need. Probably the right answer.

The determining factor may be other constraints imposed by your assignment. Is it a demostration of concept, or something that could essentially go right into production? Does it have to be something that isn't PC based?

You can use small micros to accomplish your task, but it may make the software task much more difficult. If there are not any restrictions on what you use, consider a single board computer that is basically a PC. A PC-104 product would have most of what you need on one board. Plus, you get the ability to add expansion boards for relay and motor control fairly easily. A DOS OS would probably be adequate, but a linix would also suffice. Either would make software development much simpler. It does not seem that you have much in the way of hard real-time requirements.

You might also check out web sites on robotics. Many of the parts you need should be readily available there.

Scott

Reply to
Not Really Me

Wiznet has an interesting chip, the W5100. It looks to be 4 AF_INET sockets on a chip, fully configured from the microcontroller you attach to it. We're in the process of making it work for us, so I can't say much yet from direct experience. ISTR Circuit Cellar Ink ran a design constest around it lately.

Mel.

Reply to
Mel

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The netburner PK70 is the toy. web server, hardware interface, you got it. The code is all ready for you to add the web page and examples to move digital signals on one of the "blade" cards. no programmer required, just a windows environment/pc

Chris

Reply to
Chris_99

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We actually are suppose to design a built it as a project for our employer. So we have to physically design and purchase all the pieces of the Pill Dispenser, also we have to create a website for the caretaker to program the Pill Dispenser with. I guess the easiest method would be to buy a micro controller that is kinda of an all-in-one which includes the features of Ethernet and memory and outputting signals to a display,speaker and motor. Programming would also be made easier too I suppose if its all on one board, hopefully these project won't be too complicated to program although there is a lot of that to do.

Thanks for the advice.

Ted

Reply to
tlo57

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I'm actually highly considering the PK70 the more I research and read about it. It seems to include everything that is needed to run the Pill Dispenser and more, the only drawback is the price and hopefully even though we have a decent budget we don't want to go overboard so I'll talk it over with my team.

Thanks for the help, Teddy

Reply to
tlo57

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I was researching it for a few hours now and I'm not sure how stepper motors are controlled but I'm guess Pulse width modulators. The PK70 does not have a PWM feature. I have to do a little more research but the microcontroller needed for the pill dispenser needs to be able to interact with a stepper motor.

Ted

Reply to
tlo57

No. Stepper motors use electronic commutation - it isn't as simple as a single series of pulses. You need two co-ordinated pulses, one for each coil, and both have to be able to change polarity in some manner.

There are at least three basic methods of controlling a stepper. The first activates each coil in turn. The second operates both at the same time and provides greater torque at the expense of increased power, and finally you can combine both approaches which provides greater resolution at the expense of greater complexity. The first and second options have four steps per cycle (which with built in gearing may not be the same as a revolution of the spindle). The third has eight steps.

The second approach is easiest since you never have to turn the coils off, just change their polarity, which means that each coil may be easily controlled by a single digital output via an H-bridge. There are ways of mapping the off state to a microcontroller I/O pin by using the Hi-Z input state as a third condition, but it adds complexity.

Your pulses to each coil (A and B) for this second option go:

1) Begin with both A and B polarised one way. 2) Reverse the polarity of A. 3) Reverse the polarity of B. 4) Return A to its original polarity. 5) Return B to its original polarity, that is to the same state as 1). Repeat the cycle.

If you're pushed for I/O pins and never need to reverse you can put this onto a single I/O pin, Connect it to two T-type flip flops which generate the signals for A and B. Ensure that the waveforms from each flip flop are 90 degrees out of phase.

See

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. I've only looked at this briefly but it seems to cover the essentials.

--
Andrew Smallshaw
andrews@sdf.lonestar.org
Reply to
Andrew Smallshaw
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It looks like your specifications are a little loose at this moment. Rather than worrying about what micro you need this early consider making the specification document tighter and, more importantly, correct.

With the clues you have given already you are into more than one processor. I can envisage that there will probably be a PC for the web end maybe a processor at the device end that handles the communications part and device security. The dispenser itself should be fairly simple after those aspects are taken care of but I would not mix the dispensing and the device communications on the same processor and I would have sanity checks between the two parts.

Pill dispensing is, and always should be, seen as a safety related project and were I your tutor marking the project, I would want to see that you considered the safety aspects of the system. I would want to be sure you had taken into account all the possible varieties of potential failure in a properly organised risk assessment for the system, a decent safety case for why the chosen methods will work and, if it comes to it, a reasoned argument for not building the project (sometimes it is better not to build a system you cannot provide a level of comfort for the Safety Integrity Level you say it meets. Programmable Electronics at SIL

5 are extremely difficult, if not impossible, to prove).

Once you have improved the specification (without launching into making design decisions) you should see the best way forward. Keep your design options open until you have tested the specification.

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Paul E. Bennett...............
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Reply to
Paul E. Bennett

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I am a fan of ST L297 and their H drivers L298. You only have to provide pulse and direction bits. 2 lines.

There are other far cheaper unipolar, bipolar, chopped bipolar drivers from various manufacturers as well. You will need to do a little study to get the stepper chip exactly where you want it as per drive method, motor size, half or full step, power draw, etc.

Chris

Reply to
Chris_99

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