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  • How to Burn a Bootloader to Clone Arduino Nano 3.0

    Many thanks!I just followed these instructions and they worked perfectly.I was going to mention that you don't have to use the ICSP header because all of the pins on this header are connected in parallel with existing pins, but it seems MilosG7 beat me to it (by a about a year).

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  • PossumT commented on Jeff Haas's instructable How To Make A Fake Geiger Counter2 years ago
    How To Make A Fake Geiger Counter

    Thank you :)The grill at the bottom was a case of necessity being the mother of invention. I had originally intended to just drill some holes in the plastic, but they didn't look very good, so I covered them up with an off-cut of heavy-duty mesh.

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  • PossumT commented on Jeff Haas's instructable How To Make A Fake Geiger Counter2 years ago
    How To Make A Fake Geiger Counter

    This Halloween I decided to make a fake Geiger counter. I thought I'd do a web search to see if someone had done it before (no use reinventing the wheel) and I came across this page. Excellent work! I made a few changes to the design:1) The Arduino environment allows you to configure inputs with an internal pull-up, so you can get away without using the external 2.2 k pull-up resistor. Not a big deal, but it doesn't hurt to reduce the component count. I also omitted the LED as suggested.2) I can see that the code was written by someone with an embedded controller background. It's very efficient, but it's quite difficult to follow and doesn't take advantage of the built-in features of the Arduino environment. I've created a simpler program which does the job. The ramping up/down of the c...

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    This Halloween I decided to make a fake Geiger counter. I thought I'd do a web search to see if someone had done it before (no use reinventing the wheel) and I came across this page. Excellent work! I made a few changes to the design:1) The Arduino environment allows you to configure inputs with an internal pull-up, so you can get away without using the external 2.2 k pull-up resistor. Not a big deal, but it doesn't hurt to reduce the component count. I also omitted the LED as suggested.2) I can see that the code was written by someone with an embedded controller background. It's very efficient, but it's quite difficult to follow and doesn't take advantage of the built-in features of the Arduino environment. I've created a simpler program which does the job. The ramping up/down of the click rate isn't as sophisticated as in the original design, but sounds good enough to me. Here is the code I used (hope it displays OK):/* Fake geiger counter V1.0 By Possum Dreaming 2016 D18 is connected via a switch to GND, pressing the switch makes the counter tick faster D19 goes to a transistor which drives the speaker */ #define SLOW_TICK_DELAY 80 #define FAST_TICK_DELAY 5 int max_off_delay; void setup() { pinMode(18, INPUT_PULLUP); pinMode(19, OUTPUT); max_off_delay = SLOW_TICK_DELAY; } void loop() { int off_delay = random(max_off_delay) + 1; for (int i = 0; i < off_delay; i++) { // Poll the button while waiting // Button pulls down, so 0=pressed 1=released if (digitalRead(18)) { // Released, so ramp speed down (i.e. increase the delay between ticks) if (max_off_delay < SLOW_TICK_DELAY) max_off_delay++; } else { // Activated, so ramp speed up (i.e. decrease the delay between ticks) if (max_off_delay > FAST_TICK_DELAY) max_off_delay-=2; } // To make the ramp up less jumpy, we exit the delay loop at once if the maximum delay has reduced to below the current delay. if (max_off_delay < i) break; delay(20); } digitalWrite(19, HIGH); delayMicroseconds(100); digitalWrite(19, LOW); }For anyone using this code, the line delayMicroseconds(100); determines the width of the "click" pulse sent to the speaker. You might want to adjust this value to suit your individual speaker. Too small a delay reduces the volume and too long a delay sounds less like a click.BTW, I changed the I/O to D18 for the input and D19 for the output simply to make it easier to connect to the board I had. 3) I didn't have an audio amplifier to drive the speaker so I simply drove the speaker directly using a small NPN power transistor (see the attached schematic). You could also use a MOSFET.If you do this, you will have to use code I've provided and not the original code. The original code appears to produce a square-wave output rather than a short discrete pulse for each click. This is fine when using an audio amplifier coupled via a capacitor like in the original design, but when driving a speaker directly like I did, it puts DC through the speaker coil for the entire positive portion of the wave. This would give an average power dissipation of around 2 W, which will most likely burn out a speaker designed for more like 0.5 W.4) I used 4 AA cells rather than 3 to give me a bit more headroom when using old batteries. Also, the speaker was powered direct from the batteries so that I didn't stress the on-board regulator of the cheap Chinese Arduino clone I used.

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