I understand that the Hex buffer will take a TTL input and sink or source a larger current and voltage on the output side, is there a common IC that does the reverse i.e. takes a 6,7,8 or more volt input and converts it to TTL on the output side, with some protection in between ? If switching speed is a priority is an opto isolator my best option ?
I have a board I ripped out of a very old phone to practice on
Here is the new diagram
Also on the solder points are spots B and C acceptable or do I need to be going over the previous solder point like A?
You said "You want to solder to that resistor anyway to limit current to the transistor's base - whatever you do, don't solder to the base of the transistor, as you may end up drawing too much current and burn out either the resistor (or the Arduino's port)."Where am i meant to put resistors and what value? or do you mean I should trace it out to the resister and solder to the resistor rather than one of the points off the chip?
Go for it on the photos and if you need any others for your story let me know. I am very appreciative of the help and if that can help you back in some small way I am happy to help!
So now I have the wires in the next step is take the IC out? Why am I taking the IC out? Because the arduino is going to replace it?Once I have done that what next?
Hi Cr0sh, Destined,I just wanted to point out to avoid confusion that while I have been asking questions in this thread, I am not the original poster. I trust this is not a problem for anyone as the questions are relevant and also relate to a radio controlled car.
Just to clarify why I am looking for an input buffer, my receiver operates on around 6v, at present I have this connected to an Arduino interrupt through a 1K resistor. It works very well, noise from the FETs and Motor is not a problem however I am concerned about putting 6V into an Arduino Pin. I did try a quick and dirty work around with a series diode to drop some of the voltage but would like a cleaner long term solution.
In looking through the 7400 Series ICs, I see many buffers, some that have protection in the form of built in voltage clamping diodes, but they all seem to be designed to buffer demanding outputs rather than buffer/protect inputs, is this because the opto-isolator is the preferred solution in this application ?
Hey DuaneB I don't mind at all if you post in this, but you might get better answers in your own (however you seem to of got pretty good answers in this one ).I have moved through all the steps. My soldering was better than i expected . I managed to find a black and red wire and using blue for the controls.The car doesn't appear to have a turbo. Looking at the bottom of the board, the point doesn't appear to go anywhere so this would make sense.Forward/back/left/right all work and the left and right flick back into position when I remove the probe. I love the idea of labelling the wires, i haven't done it but I am going to buy some stickers to fold around them because it will really suit my purposes in the long run!
So what should I (we) do next? (by the way I almost have my arduino running with a wifi shield, so looking forward to controlling it from my phone!).
kind of an aside cause we aren't there yet.Will it be possible to run the motors slower? Will it be possible to turn the wheels in increments rather than just left or right? (I am guessing the answer to the second is definitly no). Will I be able to power the arduino from the cars battery?
What sort of things should I be looking for to be able to do those things? (i bought the cheapest truck i could find in order to test, but if this works out I plan to spend more to get one which can do those things).
Again thank you for your time and patience. You are giving me way more help than I ever expected to get.
Ok success.I can now control forward/back/left/right from the arduino, which is what i set out to do.
However when running the PWM pin i run into problems.running fast like analogWrite(forwardPin,250); //I am using pin 9works fine.Running say 50% likeanalogWrite(forwardPin,125);Works for a while, but then a high pitch tone comes and the motor starts to slow to a stop. I just turn it back to full speed cause I don't want to break it. Does this mean PWM isn't suitable for this motor?
Do I need the probe wire from VDD for anything now?
Note: I haven't taken the IC or antenna out yet, I still wanted the car to be able to run that way for now. So I don't know if the IC is part of the problem.
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