12
votes
Accepted
What is this component? What is its purpose?
It is a ceramic chip antenna, and it does what antennas usually do.
Its specs (but not its make and model) are in chapter 7 of the module's datasheet which can be found on Adafruit's website.
Maybe ...
- 9,205
9
votes
Accepted
Can breakout board still be used if the pad gets ripped out?
It is only a double sided board. You should be able to salvage this, though it will be ugly.
You cannot simply install a new pin header and go on. Many of the traces to the eyelets are broken - you ...
- 71.4k
9
votes
Accepted
Why am I detecting two I2C addresses on the same board, and why do neither of them appear in the datasheet?
The I2CADDR pins are used to set the address of the device.
Some of the bits in the I2C address are not selectable. Those are the 4 MSBs. The 3 LSBs in the address are selectable by HW. The address is ...
- 441
7
votes
What is this component? What is its purpose?
https://www.adafruit.com/product/3406?amp& check this video out. It explains every single compenents on it. So, according to video, it is the antenna.
- 457
6
votes
Accepted
Some basic questions about an accelerometer's unexpected behavior while tilted
The vector magnitude is constant regardless of orientation, but you are applying offsets in one direction which throws off the symmetry.
You can't calibrate away gravity in only one orientation and ...
- 56.7k
6
votes
Adafruit SSD1306 scrolling function
display.startscrollright(0x00,0x0F); will print a text scrolling towards the right. What are the arguments "0x00" and "0x0F for and what kind of arguments are they?
The short answer is that those ...
- 17.9k
6
votes
Accepted
I2C Connection with ADS1115 not working
You are powering the chip from 5V but want to communicate with it using 3.3V levels. The chip requires the I2C bus voltages and supply voltage to match. Either change to 3.3V supply or add a level ...
- 149k
6
votes
Why am I detecting two I2C addresses on the same board, and why do neither of them appear in the datasheet?
Both two addresses do match the addresses listed in the datasheet.
Even the address configuration pins look like they are working.
The I2C pins do have pull-ups. You need to look at the schematic of ...
- 149k
6
votes
Can breakout board still be used if the pad gets ripped out?
Use lead based 60-40 wire solder.
Use a clean well tinned iron.
Iron should ideally be temperature controlled.
Clean iron tip by wiping on a clean rag or suitable sponge (some melt).
Material from '...
- 150k
5
votes
Accepted
Noob questions about my accelerometer (ADXL345) and Arduino components in general
ADLX345 is a chip manufactured by Analog Devices. What you bought is a module that contains that chip, and many other manufacturers make different modules which contain the same chip, but they might ...
- 149k
4
votes
Making a 5 V to 4.2 (or 3.7) V output converter with an output current of 500 mA?
You don't need to do this, you can directly power it from your 5V supply using the VBUS pins (JP3 pin 3). The board already includes the necessary power management circuitry to generate the 3.3V ...
- 2,416
4
votes
Why am I detecting two I2C addresses on the same board, and why do neither of them appear in the datasheet?
They both look like the addresses in the datasheet. Page 10 says the addresses are 0101 0XXXb and 0101 1XXXb, the X values depend on the address configured using the I2CADDR, which you can apparenlty ...
- 4,136
3
votes
Accepted
Safely measuring high-side current using Adafruit INA219
I'll keep it brief -- feel free to add comments if you need more clarity.
A snubber diode is nothing more than a diode in parallel with your load in reverse polarity. It essentially gives the back-...
3
votes
Accepted
Can someone help me understand this code for the ADXL345 accelerometer?
The 16-bit values are transferred as 8-bit bytes so one of the bytes contains the high 8 bits and the other contains the low 8 bits.
Just like us humans understand the number 42 as containing a digit ...
- 149k
3
votes
Can someone help me understand this code for the ADXL345 accelerometer?
I've redrawn Figures 49 and 50 from the ADXL345 datasheet to make it clearer.
Right-justified data format
C++ code examples to merge right-justified registers and convert to floating point. Sign-...
- 910
3
votes
Making a 5 V to 4.2 (or 3.7) V output converter with an output current of 500 mA?
You would use a regulator circuit. Since the current required and the voltage difference is low, a low dropout linear regulator would work. A step down or buck switching regulator would work as well. ...
- 73k
3
votes
Accepted
How to properly use i2c.writeto_then_readfrom() method
You're appending to the wrong thing. append is a method on bytearrays, and so is invoked on the object you want to append to, in order to pass that object in to ...
- 14k
3
votes
Accepted
Why do MCU dev boards include multiple voltage regulators?
The reason they seem to be doing it here is to allow the I2C circuitry to be powered off separately from the rest; note that there's a signal line (I2C_PWR) going ...
- 32.6k
3
votes
Why do MCU dev boards include multiple voltage regulators?
It reads on the Adafruit web page for the product. Usually if a product has some feature, the explanation and usage are listed in product description or manual.
The secondary 3.3V regulator can be ...
- 149k
2
votes
Transferring Circuit to Solderable Mini Breadboard
Yes, that solderable board is different from the breadboard. As you say, there are no power rails on it, so if you're going to use it, you need to add wires for power.
Or you can buy a board that ...
- 1,390
2
votes
Some basic questions about an accelerometer's unexpected behavior while tilted
You probably haven't allowed for gravity. An accelerometer can't tell the difference between acceleration and gravity. So there always appears to be an acceleration of 1g (9.81 m/s²) downwards.
You ...
- 19.2k
2
votes
UART CTS/RTS vs Data Format
No, CTS and RTS do not replace stop/start/parity bits.
They are handshake pins that are used to signal that when a device is ready to accept data or busy doing something else so data must not be sent.
...
- 149k
2
votes
Accepted
UART CTS/RTS vs Data Format
No, RTS/CTS clearly cannot replace start or stop bits, they serve an entirely different purpose. They control the so called "data flow" (whether the device is ready to accept data). Most ...
- 692
2
votes
Accepted
Please help identify the positive and ground for BLE antenna
The driven connection to the antenna is that fed by the series
component.
You will find on close inspection that the other terminal is ground.
It's not really correct to say that the driven terminal ...
- 33.5k
2
votes
How to add power switch to Adafruit Feather32?
All Feather boards have an "EN" pin which stands for "Enable". Simply put your switch between the EN pin and GND (to pull the EN pin low) and the voltage regulator will be disabled ...
2
votes
Why do MCU dev boards include multiple voltage regulators?
Probably a little bit of both. The SoC datasheet specifies a minimum power supply capability of 500mA, which is rather close to the 600mA limit of the AP2112K and leaves precious little current ...
- 18.4k
1
vote
Can someone help me understand this code for the ADXL345 accelerometer?
Here is "how" are the data read ... in this library
void ADXL345::readXYZ(int *x, int *y, int *z)
{ readFrom(ADXL345_DATAX0, ADXL345_TO_READ, _buff);
//read the acceleration data from the ...
- 13.3k
1
vote
How do I know what voltage logic board I'm using (Arduino Uno and accelerometer)?
The Uno runs off of 5V; the 3.3V pin is for powering things that specifically need it. Your accelerometer module can run off of either since it has its own 3.3V regulator onboard (edit:) but the ...
- 18.4k
1
vote
How do I know what voltage logic board I'm using (Arduino Uno and accelerometer)?
The microcontroller on the Arduino Uno (ATMega328P-PU) runs off of 5V, and thus all I/O coming from the digital pins will be 5V maximum. The 3.3V is a bonus output, and is unrelated to the logic ...
- 508
1
vote
Accepted
I2C voltage levels and inter-operability with Sparkfun Boards
In general it is possible to interoperate 5V and 3.3V systems with I2C - provided that (a) you pull-up to 3.3V and (b) the minimum high-level for the 5V side is below 3.3V. You’d have to look at ...
- 7,305
Only top scored, non community-wiki answers of a minimum length are eligible