Search found 1019 matches

by n1ist
Thu Aug 02, 2018 12:15 pm
Forum: Projects
Topic: Prototyping and I2C
Replies: 3
Views: 94

Re: Prototyping and I2C

Assuming that all of the sensors are 3.3v parts, connect the Feather's SDA to the first sensor's SDA; from there, connect it to the second, etc. Do the same with SCL. https://www.societyofrobots.com/member_tutorials/files/SoR_tut1_html_649df559.gif Make sure only one board has the pullup resistors o...
by n1ist
Sun Jul 29, 2018 7:25 pm
Forum: Projects
Topic: Battery Monitoring System
Replies: 1
Views: 85

Re: Battery Monitoring System

From the looks of it, there are two Arduinos - one monitors the battery, and the other acts as a serial-based terminal with a SPFD5408-based TFT display. Note that there are two programs in the zip file. BTW, the devices RB1 - RB6 are 6 relays with DPST contacts and 12 volt DC coils. Note also that ...
by n1ist
Fri Jul 20, 2018 4:34 pm
Forum: Wireless/RF
Topic: ESP8266 Thing analogPin/analogRead
Replies: 6
Views: 302

Re: ESP8266 Thing analogPin/analogRead

Pass the current through a resistor and measure the voltage across it
/mike
by n1ist
Thu Jul 19, 2018 5:23 am
Forum: General Chit Chat
Topic: Fixing cheap Chinese LED light
Replies: 3
Views: 266

Re: Fixing cheap Chinese LED light

The zeners are there so that if one LED opens, they will close the circuit and keep the others lit. The zener voltage is slightly higher than the LED forward voltage so the zeners don't conduct during normal operation. If they are shorted, they will keep the parallel LED from lighting. The current t...
by n1ist
Sat Jul 14, 2018 2:05 pm
Forum: Arduino
Topic: Pin function on board from Ebay
Replies: 2
Views: 108

Re: Pin function on board from Ebay

That is one of the more common pinouts for an RC servo, so most likely, the S is for servo.
/mike
by n1ist
Tue Jul 10, 2018 7:05 pm
Forum: Arduino
Topic: Connect arduino to phone line
Replies: 3
Views: 320

Re: Connect arduino to phone line

It's not that bad... Cermetek (which looks like it has the Xecom line now...) has the XE0092 for $25. That part handles the bidirectional audio interface, hook switch, and ring detect in a safe and legal manner.
/mike
by n1ist
Tue Jul 10, 2018 8:35 am
Forum: Arduino
Topic: Connect arduino to phone line
Replies: 3
Views: 320

Re: Connect arduino to phone line

You are looking for a device called a DAA. They used to be very common, but seem to be rarer now that everything is going cellular. Cermetek still sells them. Ixys and SiLabs both have DAA chipsets that would also work. Phone lines are quite nasty places electrically (similar to cars...) with spikes...
by n1ist
Mon Jun 25, 2018 6:10 am
Forum: Arduino
Topic: nRF24L01 Transceivers Not Working
Replies: 3
Views: 122

Re: nRF24L01 Transceivers Not Working

teprojects1 wrote:
Mon Jun 25, 2018 1:16 am
capacitor of at least 100 ohm at +3.3V and GND.
Make that 100 microfarads...
by n1ist
Mon Jun 11, 2018 6:22 am
Forum: SparkFun Product Questions
Topic: SparkFun Differential I2C Breakout Termination Resistors
Replies: 2
Views: 99

Re: SparkFun Differential I2C Breakout Termination Resistors

I looked over the board; I agree with you that the way to disable termination is to remove the resistors. Given that there's only one connection for the differential i2c and ideally you would have two for your application, it may be easier to spin your own board with the PCA9615 and BME280, with the...
by n1ist
Thu Jun 07, 2018 8:53 am
Forum: SparkFun Product Questions
Topic: SX1509 combined with HX711
Replies: 2
Views: 127

Re: SX1509 combined with HX711

The HX711 is an SPI device. To talk to it, you need to need to wait for DOUT to go low, then clock it 24 times, reading DOUT each time and assembling the answer. When you connect it to the Arduino directly, you are using the Arduino's SPI logic to do the clocking 8 bits at a time behind the scenes, ...
by n1ist
Tue May 22, 2018 6:44 am
Forum: Projects
Topic: using an arduino mini in combination with a MAG3110 Magnetometer
Replies: 2
Views: 125

Re: using an arduino mini in combination with a MAG3110 Magnetometer

There are two issues - level shifting and supplying the power to the level shifter and magnetometer.
I would use a voltage regulator like the 1117 (like https://www.sparkfun.com/products/526 or https://www.sparkfun.com/products/8376) to convert the 5v to 3.3v.

/mike
by n1ist
Mon May 21, 2018 6:08 am
Forum: Arduino
Topic: Having tropuble understanding RFID module schematic
Replies: 1
Views: 96

Re: Having tropuble understanding RFID module schematic

Looking at your picture, connect + to 5v, - to ground, and TX to RX on the Arduino
/mike
by n1ist
Mon May 21, 2018 5:05 am
Forum: SparkFun Product Questions
Topic: Potentiometer on Sunny Buddy
Replies: 1
Views: 57

Re: Potentiometer on Sunny Buddy

Looking at the picture, it's the white square component with a screwdriver slot, next to the dc power jack, by the row of 4 pth connections (next to "SET")
by n1ist
Sun May 13, 2018 2:21 pm
Forum: Projects
Topic: Controlling SS on SPI with an Atmega328p
Replies: 1
Views: 136

Re: Controlling SS on SPI with an Atmega328p

The pullup resistor (the 10k between the pin and 3.3v) is a lot weaker than the drivers inside the chip. If the 328's pin is in input mode (like it is during reset or ISP), the pullup will make the signal high so the other SPI devices all leave the bus alone. When the 328 is outputting a low, it wil...
by n1ist
Mon May 07, 2018 6:49 pm
Forum: Projects
Topic: project problem
Replies: 3
Views: 221

Re: project problem

It's nice to make things generic, but in this case, I would simplify things. Definitely no need to bother with floats for this. if (updateNow) { temp = score; for (ii = 0; ii < 3; ii++) { postNumber(temp % 10, false); temp /= 10; } temp = overs; for (ii = 0; ii < 2; ii++) { postNumber(temp % 10, fal...