MP

All the components around the IC are for the current limiting circuit. You should check all of these parts for correct values and orientation. Did you leave anything out that you felt was not needed? Even the LED is part of the current limiting circuitry. MP

Rocky, here is the complete data sheet (attached) There is no difference in pin out for UA741 or LM741 in case you are wondering. MP LM741.pdf

What you are referring to is a MOD-60 or MODULO-60 counter. You can use a MOD-10 counter with one of the 74LS93s and a MOD-6 counter with the other to provide a MOD-60. Here are some links. Some are ppt, so the download will take a while. The time to wait is worth it, though. Great examples and illustrations and they have the circuit that you need. http://www.phx.devry.edu/fac/thomas/EET202/Cntrs.ppt http://tennis.ecs.umass.edu/ece221/lecturenotes/ece221-ch7-part1.ppt http://www.site.uottawa.ca/~rhabash/ELG3331LN08.pdf Good luck! MP

Billy, I came across this page the other day from my archives. I used to have this on my website when I was manufacturing boards. Perhaps the information will be useful to you. You will want to convert the inch references to mm. This is information on how to determine the hole size versus the pad size on a PC Board when you are laying it out. The older programs gave you the capability to change the size of the pads. MP PADS.pdf

There is a project in the project section of this site for a laser transciever. It might be a good building block. You can use a microprocessor to send the signal. MP

since you must have mechanical control and PIC, I suggest that you use a PIC to make a stepper motor move with some type of control for CW and CCW or speed. MP

In further investigation, it looks as though the data sheet diagram for internal circuitry is not quite right. Where it shows ground, must have some resistance built in that the manufacturer is not showing. If you look at the example circuit given in the data sheet, it also shows the power supply connected directly to these pins (internal ground). I have attached the data sheet for others to comment. My original question: Has anyone else used this chip for their steppers? I would like to verify these discrepancies before actually building something on the workbench. I have in the past used other methods for stepper control. This seems like a very easy solution for small 6 wire stepper motors. MP UCN5804B.pdf

Yes, a schematic would be very helpful. I think that you are still going to have a problem with inductance characteristics. Filtering is going to be essential to make it work. MP

Actually, the 555 timer time event only functions from the RC circuit triggering it. There is no problem with the 555 timer circuitry for longer time delays. Where most people have a problem with the 555 timer, it is usually traced to the external circutry. You can add a a transistor and usually cure any problem associated with long time delays or weak signals. This will keep the parts count down and keep you from other issues such as noise on the clock/oscillator circuit, etc. MP

The schematic would imply that the center diode is the transmit LED, which has a good current rating with the resistor used at low volt. (Most IR projects use 3V.) The schemtic would also imply that the other two devices are 'receive' since the schematic symbol is pointing the arrows toward the LED symbol. This makes sense at it would complete the circuit and trigger the transistors. In this case, mozikluvs calculation would not be correct. This is the receive part of the circuit, not the transmit. You would want a small current here. This device is switching connection to ground on or off, depending upon if it sees IR. MP

Yes, the true sine wave is the appealing part of this. The part I am currently struggling with is the current loss when using a step up transformer that is not expensive. Anyone have a good schematic that they would like to share? MP

Actually, there are network devices that use your power lines of the house to communicate on. The AC is filtered out at the other end. Another example is the ABS brake system on most cars. The sensor sends an AC signal to let the processor know the wheel is moving and a DC signal is also generated to tell the processor that the sensor is functioning. This is so that the processor knows the wheel is locked and not a broken sensor wire when the car is moving and there is no AC signal. It is all a matter of filtering out what you do not want at the other end. MP

John, do you know where that circuit is? A link? It sounds very similar to one I am making now. It would be great if I could compare what someone else has done already. MP

Darinyou, this is just qbasic or similar. You might have this already on your computer depending upon which version of operating system you have. I think at some point microsoft quit putting qbasic in the package. Win98SE did not install the program automatically. All operating systems newer than this will also not have it unless you install it separately. If you have an old DOS installation disk, you will have the program there. MP

evume, what is the problem with getting the parts? Is it government regulation? Vendor refusal to send them? Payment methods? Problem with certain shipping companies? Members of this group will need to know as they might have the same problems getting the parts to you. For example, you cannot log onto www.digikey.com and order parts and have them arrive? Please let us know the exact reason you cannot receive the parts. MP

Here is a circuit that might help with the negative supply. Easy to find parts. You might have to tweak the values a little for your application. MP

I agree. We are just shooting in the dark without more information. What model is the motor? Any links on the web where we might get more information? MP

What you might be looking at is a Throttle Position Sensor (TPS). This is used to tell the on-board computer the position of the pedal in order to make other decisions such as what gear to change in the auto transmission or to richen the fuel mixture. I am not familiar with this particular engine but I do have overall experience with automotive computers in general. I have found that the best way to control the throttle on these engines without causing other errors is to connect a cruise control servo to the throttle link at the carb or fuel injection and control the servo with electrical pulses. MP

The 74HC595 chip works very well since you can go parallel to serial or serial to parallel with a logic change. MP

Think of the commas as periods or the periods as commas. These are used differently in different continents. It means the same. MP

Here is also a good link to a 555 tutorial if you want to learn more about the capability of this chip. Have fun! http://www.meridianelectronics.ca/gadgets/555/555.html MP

I was looking at the following project: http://www.electronics-lab.com/projects/motor_light/004/index.html and in comparing the data sheet with the project schematic, it appears that there is an error. Pins 2 and 7 of the chip are internally grounded. Therefore resistors 1 and 2 are in the wrong place. You will need resistance between your supply voltage and these pins of the chip. If you follow this schematic, you will surely let the smoke out of your chip (or power source), and we wouldn't want to do that. ;) The small board layout is ok, since it does not add a trace for this. Has anyone built this circuit? Would like to know how it went. MP

The attached pdf file might get you started. This is 555 timers. There is a similar relay example in the doc. You will have to calculate your time constant with the formula provided. MP Timer_Circuits_-_555.pdf

You cannot get more current out of this one than the spec. You can, however, put two of these is parallel and get more current out. Also depends upon what you have available on the input side. As far as the build instructions, there is no difference. MP

I think this site has a book that deals with this subject. http://www.looksees.com/car-repair.html MP