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15 votes
Accepted

very lightweight low power microcontroller with memory?

I made up a small torch locator which used an ATtiny85 powered from a button-cell (CR2032). It looks like this: Other side: That currently weighs 5.9g. The battery-holder weighs 1.6g so you could ...
Nick Gammon's user avatar
  • 38.4k
12 votes

Arduino Pro Mini is burned by 12v. Can I save it?

1. Your microcontroller is probably/maybe fine; your tiny little voltage regulator is dead; here's why: Sergio, yes, you can probably/perhaps save it: your Arduino (the microcontroller--ie: processor ...
Gabriel Staples's user avatar
9 votes
Accepted

Arduino 16 MHz with only 3.3V?

Officially, no. Practically, often but not always. If I follow the datasheet to the the letter, this configuration should not work. BUT... After some test, it did work. The data sheet does not ...
Chris Stratton's user avatar
8 votes

very lightweight low power microcontroller with memory?

I would personnaly suggest an ATtiny 45/85. It is pretty much a small AVR with 5 GPIOs. You can program it with the Arduino IDE and use the Arduino as ISP. If you can design you own custom PCB, a SMD ...
Dat Ha's user avatar
  • 2,913
7 votes

Why does this Arduino Pro Mini use a capacitor on the DTR reset line?

Most USB to serial chips set the DTR to LOW on connecting, but it keeps it LOW. This would reset the arduino, but since the DTR never goes HIGH the Arduino will never get out of this reset state, ...
Gerben's user avatar
  • 11.3k
6 votes
Accepted

How to power my Arduino mini using wall socket?

I have connected the Relay and IR receiver directly to the Arduino mini. Pin 10-14 are used for the relays Ins and PWD 3 for IR output. I hope you don't mean that you have connected the coils of ...
Enric Blanco's user avatar
  • 2,114
6 votes
Accepted

Pro Mini - Using RAW pin for 3.3v input

It is not ideal, no. The RAW pin first goes into a 3.3V voltage regulator whose dropout voltage is up to 200mV (worst case). That means that you would get around 3.1V out, and it wouldn't be ...
Majenko's user avatar
  • 105k
5 votes
Accepted

Arduino PRO Mini - The pads [was "jumpers"] on the back and Low Power Consumption

Both responses are correct but be mindful that this is a SparkFun feature. An Arduino Pro Mini from China won't necessarily have the SJ1 pad. 1) Like Gerben said, the pads on the underside of the ...
MikeH's user avatar
  • 66
5 votes

Arduino 16 MHz with only 3.3V?

According to the datasheet you need 3.78V to run at 16 MHz, and 3.3V isn't that far off. I would be surprised, for example, if it stopped working at 3.77V, because that would mean that the operating ...
Nick Gammon's user avatar
  • 38.4k
5 votes
Accepted

Measuring li-ion that arduino is running from

Using the 1.1V internal analog reference to measure a draining VCC source by using a voltage divider on it You could indeed use a voltage divider, and measure a scaled-down Vcc against the internal 1....
Edgar Bonet's user avatar
  • 43.5k
4 votes
Accepted

Soldering Arduino Pro Mini's disaligned pins

That's indeed quite an problem. If you don't mind losing 2 analog pin, you could solder some jumper-wires between A4 and A2; and between A5 and A3. Then you could connect your I2C lines to pins A2 ...
Gerben's user avatar
  • 11.3k
4 votes

Arduino 16 MHz with only 3.3V?

A little test, not very scientific, but shows it runs fine on 3.3V - https://www.youtube.com/watch?v=If0eOa0Uj5I. Again, if you would like to stay withing the specification just use a "clock divider/...
Talk2's user avatar
  • 579
4 votes
Accepted

Substitute for FTDI board?

All prices in USD w/ free shipping. FT232RL breakout board: Aliexpress: $1.55 eBay: $1.81 They are probably counterfeit. A Windows driver update (AKA "FTDIgate") at one point "bricked" them but I'm ...
per1234's user avatar
  • 4,188
4 votes
Accepted

Auto Reset during programming Arduino

A Reset is necessary to activate the Bootloader and allow programming. Without the DTR signal the Reset button has to be pressed just before starting the upload from the Arduino IDE.
Mikael Patel's user avatar
  • 7,979
4 votes

How do I erase internal EEPROM on a Arduino Pro Mini

You are clearing 28 decimal bytes, but your address range is 28 hex bytes, or 40 bytes of data. Hence, the last 12 characters are untouched.
KC Tucker's user avatar
  • 396
4 votes
Accepted

Why is AREF connected to a capacitor in the Arduino Pro Mini Schematic?

On the datasheet for the Atmega328P, in the Analog-to-Digital Converter section, is the sentence: The voltage reference may be externally decoupled at the AREF pin by a capacitor for better noise ...
Nick Gammon's user avatar
  • 38.4k
3 votes
Accepted

Atmega328p clock and safe operation zone

Just let CKDIV8 set (it just sets system clock prescaler to /8). And you can set different system clock prescaler later. For changing system clock prescaler you need: #include <avr/power.h> ...
KIIV's user avatar
  • 4,752
3 votes

All the differences between Arduinos: Pro Mini & Pro Micro

Arduino Pro Mini Pin Mapping Arduino Micro Pin Mapping The Arduino page for the Arduino Pro Mini and the Arduino Micro. Microcontroller Arduino Pro Mini: ATmega328 (ATmega168 on older boards) ...
sa_leinad's user avatar
  • 3,188
3 votes

Soldering Arduino Pro Mini's disaligned pins

Easy! I like these ProMinis and use them in lots of projects. Simply exchange one of the 12 way header pin strips for a 14 way one (cheap to buy long lengths of these strips from eBay) add small ...
EurIng Jones's user avatar
3 votes

Arduino 16 MHz with only 3.3V?

I've built a few 3.3v home-brew-duinos with 16Mhz crystals (because I have a bag of 50 xtals!) - they run fine in the conditions I've put them in so far (on my desk). Some of them may be closer to ...
JRobert's user avatar
  • 15.3k
3 votes

Arduino Pro Mini Serial Monitor garbage

I had the same issue. The problem was solved in an other forum: https://forum.arduino.cc/index.php?topic=434623.0 I copy the solution here: It appears that in fact your board is not running at 8MHz, ...
pvoj's user avatar
  • 193
3 votes

How do I run multiple vibration motors from an Arduino Mini with PWM?

You can control motor PWM by using AnalogWrite() feature. Arduino Mini is equipped with 6 PWM pin, so you can use 1 PWM pin for each of you motor. Check here about more information on AnalogWrite, and ...
duck's user avatar
  • 1,258
3 votes
Accepted

How to get the ID of an Arduino?

Arduino Pro mini is based on Atmega328 which does not have a unique ID. It has only device signature which you can read if you turn on Show verbose output during upload in Arduino IDE's File > ...
Chupo_cro's user avatar
  • 510
3 votes

How do you configure ADC7 on the Arduino Pro Mini as a digital output?

This may be a little left field, but I use the ADC6 and ADC7 inputs to detect switches. I just don't use the digitalRead() function, but instead use analogRead() function. Using a resistor network ...
Gordon Waldmann's user avatar
3 votes
Accepted

Trying to explain strange behavior when attempting to do a digitalWrite to A7 on a pro mini?

You are calling digitalWrite and digitalRead with argument A7. According to the file pins_arduino.h, A7 is defined as 21. Now, the two functions are defined in file wiring_digital.c, and the most ...
frarugi87's user avatar
  • 2,721
3 votes
Accepted

Can regular Arduino pins be used during SPI?

I did not check the datasheet of the RF69, but it is customary for SPI devices to have a “slave select” input pin. When such a device is not selected, it will leave its MISO pin in high impedance and ...
Edgar Bonet's user avatar
  • 43.5k
3 votes
Accepted

Can I share the VCC (5V) on my Arduino Pro mini with multiple modules?

Yes, you can do that as long as the total current draw of the modules you attach to VCC doesn't exceed the on-board regulator maximum current output. The Arduino Pro Mini has a MIC5205 regulator ...
Enric Blanco's user avatar
  • 2,114
3 votes

Substitute for FTDI board?

Basically, you need any way to talk to the serial interface (on digital pins 0 and 1) on the Pro Mini. Remember that for programming you'll also need to be able to manipulate the reset line on the ...
cjs's user avatar
  • 594
3 votes
Accepted

How to store u-blox coordinates (lat, lng) values in doubles? [TinyGps++]

You forgot the , 8 from your println that specifies that it should print 8 decimal places. Instead you seem to have added it to the end of an assignment which makes absolutely no sense whatsoever. ...
Majenko's user avatar
  • 105k

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