Go to advanced search

by danjperron
Sat Jul 11, 2020 3:34 pm
Forum: HATs and other add-ons
Topic: How to test RS - 485 HAT with pi 4
Replies: 4
Views: 98

Re: How to test RS - 485 HAT with pi 4

Look at the documentation of your hat! On the pcb you have a jumper settings to set the 120Ω terminal resistor! It is called 120R . Set both to ON with a short jumper plug. Terminal resistor are needed at both ends of the bus. This is to kill the echo signal. It is like a wave on a beach. The 102Ω r...
by danjperron
Sat Jul 11, 2020 1:37 pm
Forum: HATs and other add-ons
Topic: How to test RS - 485 HAT with pi 4
Replies: 4
Views: 98

Re: How to test RS - 485 HAT with pi 4

You have two channels on that Hat.

Connect the two channels together.

Send something on one and check the reception on the other channel.

Don't forget to put the jumper to connect the 120 ohm resistor.
by danjperron
Mon Jul 06, 2020 10:52 pm
Forum: Beginners
Topic: Learning adc read&Setup with Ads1115
Replies: 2
Views: 685

Re: Learning adc read&Setup with Ads1115

WiringPi start to be obsolete because of abuse that Gordon got about is nice work. Some people are nasty! The current source code is not available anymore but you could find some source code from wiringpi unofficial branch Then to answer your question you need to look at the code in file ads1115.c s...
by danjperron
Sat Jul 04, 2020 12:59 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Using Optoisolators at 115200 baudrate
Replies: 4
Views: 211

Re: Using Optoisolators at 115200 baudrate

A simple note from the PDF file of the LTV-816.

The cutoff frequency is 100KHz. it won't work for 115Kbaud!
by danjperron
Thu Jul 02, 2020 3:34 am
Forum: Troubleshooting
Topic: Very slow refresh on 16x2 display via SPI
Replies: 22
Views: 508

Re: Very slow refresh on 16x2 display via SPI

ok I found the way to set the SPI baudrate without changing the library code

Code: Select all

lcd = char_lcd.Character_LCD_SPI(spi,latch,cols,rows)
lcd._shift_register._device.baudrate=10000000
by danjperron
Thu Jul 02, 2020 3:10 am
Forum: Troubleshooting
Topic: Very slow refresh on 16x2 display via SPI
Replies: 22
Views: 508

Re: Very slow refresh on 16x2 display via SPI

ok I found the culprid! The adafruit libray fix the SPI baudrate. In the file adafruit_74hc595.py the baudrate is fix to 1MHz. class ShiftRegister74HC595 line 123 __init__ function self._device = spi_device.SPIDevice(spi, latch, baudrate=1000000) just change the baudrate to 5000000. ( I thing that 1...
by danjperron
Thu Jul 02, 2020 1:18 am
Forum: Troubleshooting
Topic: Very slow refresh on 16x2 display via SPI
Replies: 22
Views: 508

Re: Very slow refresh on 16x2 display via SPI

If I try to set it to anything else using spi.configure(), nothing seems to happen, it just reads 1MHz.
Ok then I will have to dig more. maybe one of the function set the clock rate.
by danjperron
Wed Jul 01, 2020 10:17 pm
Forum: Troubleshooting
Topic: Very slow refresh on 16x2 display via SPI
Replies: 22
Views: 508

Re: Very slow refresh on 16x2 display via SPI

The default SPI clock is 100KHz. It is define in Adafruit busio.py module. No wonder why it is so slow!!! it is possible to change the SPI clock spi = busio.SPI(board.SCK, MOSI=board.MOSI) while not spi.try_lock(): pass spi.configure(baudrate=5000000) spi.unlock() Now it should be very fast with a 5...
by danjperron
Wed Jul 01, 2020 4:59 pm
Forum: Beginners
Topic: Tensorflow
Replies: 2
Views: 162

Re: Tensorflow

by danjperron
Sun Jun 21, 2020 1:39 pm
Forum: C/C++
Topic: Problem dht22 sensor when turn on the rasp
Replies: 1
Views: 136

Re: Problem dht22 sensor when turn on the rasp

Hi Sej, maybe the PI is really busy at startup and time slice too much. By doing this your timing is wrong. You could try to loop the reading every 5 seconds until you get valid results. Maybe you could increase the priority of your code. void set_max_priority(void) { struct sched_param sched; memse...
by danjperron
Thu Jun 18, 2020 10:31 am
Forum: Device Tree
Topic: Pi-4 Activating additional UART ports
Replies: 74
Views: 31828

Re: Pi-4 Activating additional UART ports

Please check the README in /boot/overlays folder. ex: Four more i2c by including this in the config.txt dtoverlay=i2c1,pins_2_3 dtoverlay=i2c3,pins_4_5 dtoverlay=i2c4,pins_6_7 dtoverlay=i2c6,pins_0_1 You need to put pull up resistor on the new SDA and SCL pin (4k7 ohm typical, One side at 3.3V the o...
by danjperron
Wed Jun 17, 2020 11:53 am
Forum: Device Tree
Topic: Pi-4 Activating additional UART ports
Replies: 74
Views: 31828

Re: Pi-4 Activating additional UART ports

This is not 68 address!

It shows that you have something at the address 68. This is normally an RTC.

Each I2C devices have their own specific address. You need to be careful by settings each device with a different address. Some have fix address and some have pins dedicated to change the address.
by danjperron
Mon Jun 15, 2020 10:02 pm
Forum: Troubleshooting
Topic: Raspberry Pi 4, Sabertooth 2x12 Tank
Replies: 6
Views: 257

Re: Raspberry Pi 4, Sabertooth 2x12 Tank

Hi Rabidgeek, I look at your image and 3.3V converter miss the 5V. a level voltage converter normally uses the two Voltages. LV at 3.3V and HV at 5V. Could you specific which is your 3vto5V converter? It could be an idea to check if your ttl serial works at your raspberry pi. First be sure that it i...
by danjperron
Sat Jun 06, 2020 8:52 pm
Forum: Troubleshooting
Topic: Raspberry Pi 4, Sabertooth 2x12 Tank
Replies: 6
Views: 257

Re: Raspberry Pi 4, Sabertooth 2x12 Tank

This post switch to french after few post. If you need any help in French I could translate!

viewtopic.php?f=65&t=128486&hilit=saber#p864024
by danjperron
Thu Jun 04, 2020 8:55 pm
Forum: Automation, sensing and robotics
Topic: Solar powered greenhouse irrigation system
Replies: 15
Views: 1030

Re: Solar powered greenhouse irrigation system

I'm doing something similar to you. I'm using a solar panel 10W with a 3.1AH 12V Battery. The Pi is a pizeroW and it is my nRF24L01 server. I gathers data from all my humidity sensor. On my root crontab I added this line @reboot /usr/bin/tvservice -o; This kill the HDMI stuff This reduces the curren...
by danjperron
Thu May 28, 2020 2:40 am
Forum: Automation, sensing and robotics
Topic: Voltage less when reading 4-20 mA sensor using ADS1115 and Pi
Replies: 10
Views: 540

Re: Voltage less when reading 4-20 mA sensor using ADS1115 and Pi

Could you make the sensor supply floating ? the Sensor (-) at the ground of the ADS115(RPI) and the (+) at in0. (not in differential). The other approach is to use resistors dividers like (6k8/10K) on both side of the 220Ω resistor. This will give you a voltage reduction of 0.405 which will allow th...
by danjperron
Sat May 23, 2020 1:26 pm
Forum: General discussion
Topic: rtcwake: /dev/rtc0 not enabled for wakeup events
Replies: 11
Views: 3240

Re: rtcwake: /dev/rtc0 not enabled for wakeup events

Yes two year old.

How much current the Pi uses on shutdown compare to my system (the post just before)?

I think the avantage of my system is that I could use a 12V battery and don't care about the 5V regulator since I controlled de regulator.

Daniel
by danjperron
Thu May 07, 2020 3:07 pm
Forum: General discussion
Topic: Only run python on rasberry pi
Replies: 19
Views: 822

Re: Only run python on rasberry pi

Use the command top or htop to figure out what is using your cpus .
by danjperron
Wed May 06, 2020 10:18 pm
Forum: Automation, sensing and robotics
Topic: Stationary Cycle Display
Replies: 30
Views: 10827

Re: Stationary Cycle Display

Try VNC viewer application on your phone.

I just need to enable the vnc server on the PI.
by danjperron
Thu Apr 30, 2020 9:51 pm
Forum: Français
Topic: 74hc595 et module 4 relais
Replies: 17
Views: 622

Re: 74hc595 et module 4 relais

Es-tu certain que ton schéma est ok. Ton transistor est en envers! Il faut mettre l'émetteur sur GND et le collecteur au relais. Sii tu branches manuellement GND sur l'entrée du relais. Est-ce qu'il s'active. Si tu branches 3.3V sur l'entrée du relais est-ce qu'il s'active. Un transistor 2n2222 est ...
by danjperron
Thu Apr 23, 2020 8:21 pm
Forum: Advanced users
Topic: Multiple temperature sensors (was Multiple moisture sensors)
Replies: 4
Views: 228

Re: Multiple temperature sensors (was Multiple moisture sensors)

Could you give the link for Multiple moisture sensors ?


I got up to 30 DS18B20 sensors on this demo. I read all of them in less than 1 second.

This video is in french. https://www.youtube.com/watch?v=b3wFJoEiXfU
by danjperron
Tue Apr 21, 2020 8:20 pm
Forum: Advanced users
Topic: How Can I Use a RPi To Interface Directly To a Z-Wave Dongle?
Replies: 8
Views: 331

Re: How Can I Use a RPi To Interface Directly To a Z-Wave Dongle?

That sounds like exactly what I want to do. But I already have an AeoTec stick. I wonder if the HTML requests are unique to RaZberry hardware or would my stick work as well. I do have the Aoetec usb device with Home Assistant to control my GE zwave light switch. It is quite simple. Also I made some...
by danjperron
Tue Apr 21, 2020 6:44 pm
Forum: Beginners
Topic: (Bis) PI3B+ gpio readall; unable to determine board type ... model: 13
Replies: 24
Views: 597

Re: (Bis) PI3B+ gpio readall; unable to determine board type ... model: 13

Which gpio version are you running right now?

Code: Select all

gpio -v
Could you post the output result of

Code: Select all

cat /proc/cpuinfo
by danjperron
Sun Apr 19, 2020 12:12 pm
Forum: Beginners
Topic: Sunwait and crontab -e, how?
Replies: 11
Views: 366

Re: Sunwait and crontab -e, how?

0 14 * * * /usr/local/bin/sunwait -v sun down 45.1234N 75.1234W; /home/pi/lamp$ This is mine to start a script to turn light on on sun down. For you it should be something like 0 4 * * * /usr/local/bin/sunwait -v sun rise offset 30:00 45.1234N 75.1234W;/usr/bin/python3 yourpythonscript.py Don't for...

Go to advanced search