You don't need a current limiter to the SX; it will consume what it does, and your job is to make sure that the outputs aren't over-driven (I use them at 12- and 24-volts [noparse][[/noparse]with proper regulation] every day). And as Terry pointed out there are elements missing from your schematic that you will find on the [noparse][[/noparse]working] project I posted earlier.
RadioShack is not a great source of parts; you might want to look at big vendors like Digi-Key and Mouser for serious components.
I had to put the 1K resistor before the regulator because if I did not, it would get hot and pop the regulator, then send too much to the chip and burn it up. Found that out first hand. [noparse]:([/noparse]
If i hook the meter up to the output of the PNP with no load, it is coming out like it should at 12V, but when I hook up the motor to it, it does not turn the motor at all. it is like there is not enough power to run it. Do i have missing components or can I eliminate part of what I have and get it to work right? I use radioshack because it is 5 miles down the road and i can pick up the parts that same day to test them to see if it works. most companies will screw you on shipping so it is a little better for me to at least test it with radioshack parts first.
eagletalontim-
I hear you about the shiping. I wish I had an electronics distributor closer to where I live (the closest is 30 miles away in Salt lake city, not exactly convienient). Unfortunately, radio shacks selection leaves something to be desired
the motor needs as much possible current as it can get. The schematic shown in one of my last posts is how it was hooked up. The 10K was connected to the MCLR, but i forgot it in the schematic. When i removed the 1K, the regulator would instantly start getting hot and i had to disconnect it. I have no idea how to read the current that the chip is using.
The radioshack down the road from me is not corporate so he keeps a good stock of all the small electronic that he can get. I get a good discount from him too [noparse]:)[/noparse]
One of the first things you'll want to do is measure how much current the motor actually uses when it is connected directly to a 12v battery. Find out what the no load current is, loaded current, and you should probably figure out what the stall current is as well.
If you just want to control a motor (on/off) then your best bet is just to have the SX processor control a relay. You can get automotive relays everywhere, many are not too expensive, and are made for switching loads like this. Schematics have already been provided in one of the links i've posted on this thread on how to connect the SX so it can control a relay.
I wouldn't try controlling any sort of motor with the method your using (unless it was a .50 hobby motor) since motors can be messy. The make all kinds of electrical noise and it's best to isolate them from your processor circuit. Using a relay will accomplish this. From all the details you've posted I feel this is probably the best option for your circuit.
with the board that I am using, i am extremely limited on space. What i am controlling on the car are solenoids. I have not been able to get the patent since i do not have a full scale working design so I don't want to give out too much info to the public. I have been working on this way too long to have someone else yank it from me. I just need help getting things sorted out.
I use DC motors as my testing to see if it will work when hooked up to my car. The solenoids are already controlled by a computer in the car and it does not use relays so it has to be able to be done without relays. I want to be able to bypass those and control them when I want.
Have a look at the schematic I've attached -- I think it meets the circuitry requirements for your project -- though you'll have to speck in the transistors based on solenoid loads, and you may need more filtering due to a car's typically-noisy electrical system. The connections are based on two threads you've started that seem to be related, and use only the RA and RB ports of the SX which means your final design could run on the SX20SS.
If it works, send me a check -- consultants have to eat, too!
well, the motors come on, but they stay on the entire cycle. should i change the resistor coming from the chip to the NPN to something larger? The NPN is sensitive to touch and can be at full power with just the touch of your finger.
ok, i followed your schematic for the regulator just to see if maybe that was part of my problem. The image attached is how I have it hooked up. I am not getting 5v out of the output side of the regulator. I am getting more like 15v that if straight run to the motors, they run perfect. Should I not be getting 5v out instead of 15v? The more i test things on here, the farther away from accomplishing this project [noparse]:([/noparse] I really need to know why i cannot simply control the positive connection for the motor without using a relay.
I've used a resistor on the input of a linear regulator, as you're suggesting, I guess, to drop the voltage at the input.· But it has to be a fairly low value and a power resistor at that (it'll take the heat that you're sparing the regulator.)
pic attached
If it won't work standing alone, if you get something other than a nominal 5V, then there's something very not right.
1K resistors are typically to high on transistors base to be fully saturated, I have seen them as low as 33ohms otherwise you will have to great of a voltage drop across the transistor. This is one thing you will need to verify rather your using a trasistor or a fet. The advantage to using a mosfet is the low on resistance with less voltage drop with higher current capabilities.
Seems like your in a very big hurry my friend! Be patient and·problems will get worked out! It is a very good idea to purchase a multimeter for doing your current checks.
I take it no one else has had heat problems with putting 12 volts into a 5volt regulator? Typical voltage on a LM7805 is 7.5volts and max 10volts.
Kevin
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Post Edited (DigitalDj) : 1/18/2008 3:18:44 AM GMT
You can use a logic drive MOSFET to control your motor right from the CHIP like this.
I made a quick schematic of a motor control for you. I did not put the 10K to MCLR
just the Programing header, the power supply and output control and· you should look at the SX 28 Specs PDF on this site so you don't burn up your chip... I hope this helps you. Sounds like you are starting to have fun with the SX Chip.. Good luck..
THE IRL510 is rated upto 100v. They make other values . I don't know what exactly you need but if you are just turning on a motor with no real control then maybe a TIP or transistor will do.. You have 2 roads you can go with out giving your circuit away.
i was unable to open the attachment datacps [noparse]:([/noparse] not sure if it is my version of the SX-Key, but it showed up as Ascii. I thought Mosfets were static sensitive. Would that not cause problems? If not, what would be the best one to use?
If all you want to do is get a patent, you don't need a working prototype. The patent office doesn't come by to see the device in action. You're patenting the idea of a device. If you want to patent "Waffles with Wings", you don't need either waffles or wings - you need a patent attorney and some money. After that, some patent office person will review it and likely rubber stamp it. Bingo! You now have the patent for "Waffles with Wings!"
Want an example? How about an antigravity device? Check out this article:
Do you really think the patent holder actually built a device that is contained within a hollow superconductive shield? I doubt it.
Of course, you do know that a patent requires full and public disclosure of exactly how your device is supposed to work, right? Once that happens, anyone who wants to copy your device can do so by simply looking up the patent. At that point, your only recourse is to sue them. Unless you sell this device to a big manufacturer with deep pockets, you're on the hook for defending your patent.
BTW, the Chinese are real big on making copies of pretty much everything these days, so I hope you or your lawyer speak Mandarin.
you do have a good point [noparse]:)[/noparse] Any suggestions on what I should do to help keep people from stealing my design?
Also. what MOSFET should i use? N-channel or P-Channel? If someone could read the Motor Control schematic posted above, can you convert it to an image so I can read it please [noparse]:)[/noparse]
It is very common to connect one lead your motor or solenoid to your positive voltage source (in your case +12v) and then use a MOSFET, Transistor, relay, etc as an electronic switch to connect the other lead to ground when you want to turn it on.
Have you visited the other links that I posted in the message about the schematic layout tool in a previous post?? The last link shows an example of how a MOSFET can be used to control a device. It specifically mentions Coil or Motor. A coil can be the coil of a relay or solenoid.
There are a lot of ways to control a solenoid and motor that you can choose from.
We can't really recommend any specific parts since we don't know what the current requirements are for the item you want to control. Take some current readings to try and find out what the current draw is for the parts you are using. Factor in a safety margin and experiment a bit.
The reason you can't open the schematic above is that there are spaces in the filename and there is an issue with the forum itself in the way it handles attachments with spaces. Just save it to your local drive, change the extension to .sch and then open it with that free schematic program you are already using.
well, in my case, it is impossible to control the ground of the solenoids. they are already mounted to the car and have to have a positive input of 12 - 14v 10A. I do not want to use relays since they have moving parts and take up too much room for the amperage that i need to control. The solenoids are already controlled by a computer, but i want to bypass it and use my design. The computer does not have relays in it so it has to be possible to send out a positive 12 to 14v 10A signal using the SX28 and transistors. I just can't figure out how to control that much without burning up the chip. Already burned up 2 of them [noparse]:([/noparse]
eagle they make PNP devices that can turn on the Positive side of the circuit. All you would have to do is send a low signal. I changed the schematic to show how it is connected..
Ok, i attached the schematic on how I have it hooked up on the board, but for some reason both motors come on at the same time when they are supposed to come on at different times. if the setting is both off, then they both turn off like they should. The Switching NPN transistors seem to be the problem, but they do work properly if run one at a time on the test board. If i hook up both of them, it acts weird. I think it may have something to do with static or something to that effect. Can a put a resistor on it going to ground to eliminate that problem. If so, what size? If not, what should I do. I am soooo close to getting it finished! next project is a robot of some sort. got 5 or more sx chips to play with now [noparse]:D[/noparse]
I would attach 10 kOhm resistors between the bases and +12V on both TIP42 transistors to make sure that they turn completely off when the inputs are low.
Next, I would remove the SX, and then apply +5V to one of the inputs to verify that the motors turn on separately. If this is the case, something must be wrong either with the controller software, or with the controller's 5V supply or ground connection.
Comments
RadioShack is not a great source of parts; you might want to look at big vendors like Digi-Key and Mouser for serious components.
If i hook the meter up to the output of the PNP with no load, it is coming out like it should at 12V, but when I hook up the motor to it, it does not turn the motor at all. it is like there is not enough power to run it. Do i have missing components or can I eliminate part of what I have and get it to work right? I use radioshack because it is 5 miles down the road and i can pick up the parts that same day to test them to see if it works. most companies will screw you on shipping so it is a little better for me to at least test it with radioshack parts first.
The regulator cannot "force feed" current into the SX. If the output is 5 volts, then the SX will consume whatever current it needs.
How much current does your motor need ? How much current is the SX using ?
Bean.
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www.iElectronicDesigns.com
·
I hear you about the shiping. I wish I had an electronics distributor closer to where I live (the closest is 30 miles away in Salt lake city, not exactly convienient). Unfortunately, radio shacks selection leaves something to be desired
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Shawn Lowe
Maybe I should have waited to do that......
The radioshack down the road from me is not corporate so he keeps a good stock of all the small electronic that he can get. I get a good discount from him too [noparse]:)[/noparse]
If you just want to control a motor (on/off) then your best bet is just to have the SX processor control a relay. You can get automotive relays everywhere, many are not too expensive, and are made for switching loads like this. Schematics have already been provided in one of the links i've posted on this thread on how to connect the SX so it can control a relay.
I wouldn't try controlling any sort of motor with the method your using (unless it was a .50 hobby motor) since motors can be messy. The make all kinds of electrical noise and it's best to isolate them from your processor circuit. Using a relay will accomplish this. From all the details you've posted I feel this is probably the best option for your circuit.
I use DC motors as my testing to see if it will work when hooked up to my car. The solenoids are already controlled by a computer in the car and it does not use relays so it has to be able to be done without relays. I want to be able to bypass those and control them when I want.
If it works, send me a check -- consultants have to eat, too!
pic attached
If it won't work standing alone, if you get something other than a nominal 5V, then there's something very not right.
Post Edit -- added 7805_2.jpg
Post Edited (PJ Allen) : 1/18/2008 1:32:51 AM GMT
Seems like your in a very big hurry my friend! Be patient and·problems will get worked out! It is a very good idea to purchase a multimeter for doing your current checks.
I take it no one else has had heat problems with putting 12 volts into a 5volt regulator? Typical voltage on a LM7805 is 7.5volts and max 10volts.
Kevin
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Post Edited (DigitalDj) : 1/18/2008 3:18:44 AM GMT
I made a quick schematic of a motor control for you. I did not put the 10K to MCLR
just the Programing header, the power supply and output control and· you should look at the SX 28 Specs PDF on this site so you don't burn up your chip... I hope this helps you. Sounds like you are starting to have fun with the SX Chip.. Good luck..
THE IRL510 is rated upto 100v. They make other values . I don't know what exactly you need but if you are just turning on a motor with no real control then maybe a TIP or transistor will do.. You have 2 roads you can go with out giving your circuit away.
If all you want to do is get a patent, you don't need a working prototype. The patent office doesn't come by to see the device in action. You're patenting the idea of a device. If you want to patent "Waffles with Wings", you don't need either waffles or wings - you need a patent attorney and some money. After that, some patent office person will review it and likely rubber stamp it. Bingo! You now have the patent for "Waffles with Wings!"
Want an example? How about an antigravity device? Check out this article:
news.nationalgeographic.com/news/2005/11/1111_051111_junk_patent.html
This one one the same sbject gives a good breakdown of the patented device:
ipbiz.blogspot.com/2005/11/uspto-issues-anti-gravity-patent.html
Do you really think the patent holder actually built a device that is contained within a hollow superconductive shield? I doubt it.
Of course, you do know that a patent requires full and public disclosure of exactly how your device is supposed to work, right? Once that happens, anyone who wants to copy your device can do so by simply looking up the patent. At that point, your only recourse is to sue them. Unless you sell this device to a big manufacturer with deep pockets, you're on the hook for defending your patent.
BTW, the Chinese are real big on making copies of pretty much everything these days, so I hope you or your lawyer speak Mandarin.
Thanks,
PeterM
Also. what MOSFET should i use? N-channel or P-Channel? If someone could read the Motor Control schematic posted above, can you convert it to an image so I can read it please [noparse]:)[/noparse]
Have you visited the other links that I posted in the message about the schematic layout tool in a previous post?? The last link shows an example of how a MOSFET can be used to control a device. It specifically mentions Coil or Motor. A coil can be the coil of a relay or solenoid.
There are a lot of ways to control a solenoid and motor that you can choose from.
We can't really recommend any specific parts since we don't know what the current requirements are for the item you want to control. Take some current readings to try and find out what the current draw is for the parts you are using. Factor in a safety margin and experiment a bit.
The reason you can't open the schematic above is that there are spaces in the filename and there is an issue with the forum itself in the way it handles attachments with spaces. Just save it to your local drive, change the extension to .sch and then open it with that free schematic program you are already using.
Robert
Just Google "high side switch"
Doug
http://www.mouser.com/Search/Refine.aspx?Ntt=*pnp*&N=1323038&Ntx=mode+matchall&Ns=P_SField&OriginalKeyword=pnp&Ntk=Mouser_Wildcards
Next, I would remove the SX, and then apply +5V to one of the inputs to verify that the motors turn on separately. If this is the case, something must be wrong either with the controller software, or with the controller's 5V supply or ground connection.
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Greetings from Germany,
G