ZBasic Forum

Wow, sounds like a fun project. Not being the least bit musically inclined I don't know what the frequency range for a Metronome ought to be, but a couple of the commercial ones in Mike's link show a top end of 4.x Hz, i.e. a very low frequency. For the 1/4 note option, then, and ISR firing at 4 tim...

Although many add an external pull up resistor on the Reset\ pin, I doubt that is the reason the OP's circuit is not working.

The Mega AVR's have an internal pull up resistor on the Reset\ pin by default.

JC

There will be some jitter But fortunately this won't be an issue for PWM'd LEDs. The other option, of course, is to use one of the many LED controller chips available these days. I still have a bin full of Darlington transistors on my bench, but I haven't used one in quite a while. I've generally s...

will apply the caps as suggested. to be clear .1 between any unused ground and/or VCC pins on the processor board and ground ? ALL of the Vcc and Ground pins on the micro are used. None of them should be left unused, (unconnected). The issue is that the M128 has two Vcc and an AVcc pin. ALL of them...

If you use a shift register, make sure to check its current rating on both a per pin and a per chip (Vcc, Gnd), basis. Lots of AVRs can drive a bank of 20 mA LEDs, so that wasn't a bad option. How far is the display from the main box? The car will be an electrically noisy environment, (RF wise, and ...

Rosariote was talking about By-pass caps. The issue is that the M128 has two Vcc and an AVcc pin. ALL of them need to be connected to Vcc. All three of the Grounds need to be connected to Ground. Both of the Vcc and the AVcc pins should have a By-Pass cap, typically a 0.1 uF cap placed as close to t...

I would think the first step is to try to determine if the interference is EMI, (RF), entering the wiring harnesses, noise on the power supply bus, noise on other input signals, the clock frequency, or of other etiology. Regarding the cap on the Xtal, If the system was stable and error free for seve...

Sounds like an interesting project. I wondered why you decided to have the IR emitters at multiples of the base frequency? Special reason, or just did it that way? When doing data discrimination it is often easier if the signals are NOT multiples of each other, as if one is doing FFT/DFT analysis th...

Also, is there a By-Pass capacitor from V+ to Ground, as close to the micro's pins as possible, (e.g. 0.1 uF)? This is required for reliable operation, especially in a noisy motor control circuit. Also, check you specific crystal's spec's. 27 pf might be a bit high for many crystals, especially if o...

Also, I did not see the number for the switching transistors.

One assumes they are logic level devices and switch fully on with the logic level gate signal, and that they can handle the STALL current of the motor, not just the running current, with an ample safety factor.

JC

Probably worth having a look at this link: http://www.avrfreaks.net/index.php?name ... c&t=137489
on AVR Freaks, regarding automotive control software.

JC

Which micro are you using? Before you get too far in your design you might want to program the Timer/Counter in PWM mode and output 100% and 0% and then measure the output voltages with an O'scope or DMM. The high might be ~ 4.5 V on a 5 V micro, not 5 V. Likewise the low might be a few tenths of a ...

Another option might be to look at the AVR Xmega. I believe the Xmegas have an "Advanced Waveform Extension" (AWeX) mode which generates complimentary outputs on two pins with a built-in "dead time" to prevent "shoot-through" currents. I've not used it, or looked at the...

Man, times have changed. I recall building a cruise control with an 8085 micro. The micro read the vehicle speed from 3 magnets mounted on the front axle, and a coil to pick up the pulses. There was a throttle linkage in parallel to the one from the gas peddle. The micro controlled a solenoid valve ...

My understanding is that a USB device can expect the host to provide up to 100 mA when the device is first plugged in and enumerated. The device can then send a request asking for up to 500 mA current, but the host does't have to grant that request. Additionally, if the device tries to draw more tha...