# Tag Info

## New answers tagged raspberry-pi

0

Even a 200 W PSU can supply about 15 to 20 A at 5V rail. I dont know how will be the relays' frequency of switching or if all of them will switch at the same time, but a normal PSU can handle this. If you experiment some problems, just add a capacitor of about 4700 uF to the power cable, place it near RPi. But I think that it will not be necessary. But ...

0

Computer PSUs tend to be nicely designed. At least the big name ones. They of course arent used to drive solenoids and relays. There may be noise when the solenoids are powered on or off. The noise is unlikely to damage your RPi but it can cause other noise issues like brownouts or false readings. The simplest solution would be to keep your 3 supplies and ...

2

@BrianDrummond's suggestion is best. Find a range for the Vf at your current and (and over the applicable junction temperature range) apply a window comparator to the voltage. We use exactly that method to detect failure in an IR LED (or connections to it) since the obvious "visual" indication is not available. I've seen partial failures in some LEDs that ...

0

The IN must be pulled down to ground to turn on. It must be pulled up to VCC to turn off. At 3.3V IN there is still a difference of 1.7V and that may result in current through the optocoupler so it may not turn off. And when HiGH-Z or ground the gpio would send 5V potential through it. As long as you are sure VCC and JD-VCC are isolated, then VCC should be ...

2

You really should want some hysteresis in the circuit. This can be achieved pretty simply: simulate this circuit – Schematic created using CircuitLab The output will be HI to the I/O pin when there is no light and it will be LO when there is sufficient light. Feel free to adjust $R_2$ up or down a bit in order to select the desired light level for ...

3

I would suggest you pull the gpio pin up to 3.3v using a sizeable resistor ,and then pulling down that same pin by connecting it to the collector here is a Quick solution , please calculate the values depending on the components you are using. simulate this circuit – Schematic created using CircuitLab hope it helps.

1

They are not different than many MCU GPIO pins. Unfortunately the datasheet has no block diagram at all to explain this. The pins have direction control register to set the pin direction between input and output. Basically it just controls if the output buffer is enabled or disabled. When output buffer is enabled, the pin is a push-pull output which drives ...

2

According to this thread on the Raspberry Pi forums, it is a known issue that the Pi 4 will not boot if power is present on its USB port. There is some evidence that switching to one of the USB 2.0 ports (rather than the 3.0 ports) solves the problem. EDIT: OP tested this and it doesn't solve the problem. You can also get into the USB cable between your Pi ...

0

Yes, you could just theoretically connect +5V pin from Arduino to Raspberry 0V pin, and so you could obtain 10V when probing +5V pin of Raspberry to 0V pin of Arduino. But DON'T DO IT. Besides of getting two points that can be measured as 10v potential with your multimeter, this setting will be of no utility at all. You can't connect Arduino to Rpi (...

0

For those who might face a similar problem in the future, after some digging I believe the answer to my issue is the follows: When using the LED simply as originally described (Cathode to A1, Anode to A0), the voltage depends on the resistance between the pin, which in the ADS1115 is gain-dependent. This is why the gain alters the voltage and ADC values in ...

2

No. The pins are already all connected in parallel, you can't change that.

0

This isn't a direct answer to your question, rather an alternate way to solve your problem. You could unsolder one of the remote control RCA connectors from the PCB, then replace it with a bulkhead RCA connector going to a 2-wire cable, then to an IR LED placed inside the amplifier right next to the amp's IR remote control receiver. Make sure the IR LED ...

1

I have these LEDs too. There's a tiny potentiometer (near the black wire in your picture) which adjusts their brightness and changes how ambient light affects the light induced shutoff. If you turn them up too bright (without adequate heatsink) they start flashing. I don't know if this is a safety feature or a failure mode, but if you turn down the ...

1

I have now returned to this project of mine, I have finally realised my silly mistake. According to the typical connection diagram there should be a 5.1Ω resistor between VA and VD pins, but I accidentally originally put a 5.1kΩ resistor there. After replacing the resistor with the correct one the ADC works all right.

1

Michael Karas' comment contained the answer i needed. once the level shifter was powered on both the hv and lv sides from the respective 5v and 3v sources, the shifter gives the right 3.3v shifted voltage from the data0 and data1 pins.

0

Apparently the problem you are facing has been reported before, and it lies on the pull-down resistors of the Raspberry 4. In short, there should be independent resistors for the CC1 and CC2 lines in order to detect the operating mode according to the following: Quoting the prossible problem description: In the correct operation the charger will sense ...

0

The crystal oscillator circuit is not oscillating because there is a missing 1 Mohm bias resistor between the crystal terminals.

0

This seems to have gotten rid of the errors for me Go to the config file for the raspberry pi interface, this is most likely located in: /usr/share/openocd/scripts/interface/sysfsgpio-raspberrypi.cfg Add sysfsgpio_srst_num 7 Save the file, it should run now EDITED: Edited because of comment that the original way wasn't the way to go

1

It says to not use a "surge protector" power strip, if you avoid those, then you will be fine, providing your within the load limits of the UPS

0

The RPi can definitely be used to supply a ground connection! I would recommend looking into the gpiozero python library and specifically at the 'buzzer' output device.

1

For what your asking. It would be either a involved piggyback or a gutting of the original system. For the piggyback it would be finding a way to insert a video signal. E.g. some in car dvd systems have a hdmi input. Or at a minimum a reversing camera input. If that works then its just hijacking the touchscreen data when your in that mode. Most of these ...

1

If you are sincere about clean signals, then implement "local battery" for each module. The "local battery" requires slightly modifying the common_VDD wiring. You must modify VDD FOR EACH MODULE by installing 100 microHenry in series, followed by the module in parallel with 100 microfarad. Of high importance in success with "local battery" is WHERE TO ...

3

To keep the input voltage to the buck converter from dropping down to some really low value during the inrush current period of the 150 watt motor, use a diode and capacitor. This will "hold-up" the voltage at the input to the buck circuit despite it dropping down across the motor. The diode gets reverse biased during this short period and therefore the ...

1

The buck converter apparently can't keep up with the abrupt change in input voltage. A cap probably won't be enough to smooth the voltage drop, but if you are willing to build a circuit, you could put in a capacitance multiplier to smooth it much more effectively. This solution could work if the voltage drop is not in fact much more severe than a few Volts. ...

1

If the power converters & supplies you have are well-made, they should already have capacitors in parallel between the +5V and ground lines to smooth any jumps in voltage. However, you can definitely add a cap as close to the RPi as possible to smooth out the voltage even more. The problem is also coming from the RPi triggering a power hungry device, so ...

1

No need for individual sensors. Instead, make the bottom transparent; aim a camera at the cup bases. Use opencv running on the Pi to detect the objects and tally them. For the lights, use an addressable RGB strip. You can singulate the lights physically as needed to mount them next to the the cups.

0

Based on the datasheet, your 3.3V gate drive should be enough. Are you absolutely sure that you are using the MOSFET that goes with that datasheet? Have you verified that you are actually getting 3.3V out of the RPi GPIO? If you want to use the 12V to pull up the gate drive to the MOSFET, you can add another transistor and some resistors to do that. Here is ...

1

Generally speaking there are many reasons why a microcontroller/single board computer GPIO pin might not be suitable to drive the gate of a MOSFET. You may be able to use a single lower power 'logic level' MOSFET as a gate driver, but I don't recommend this. For a low side driver such as this you will have the best results using a MOSFET gate driver IC, ...

0

The IP address of your MQTT host as defined in your code is probably wrong. The 169.254.x.x that you refer to in your code is a kind of "emergency" link-local address, from a range also called "APIPA" (Automatic Private IP Address). Such an address is assigned by the Operating System to a network interface, configured to work with a dynamic IP address (DHCP)...

Top 50 recent answers are included