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by PiGraham
Thu Nov 05, 2020 10:22 am
Forum: Python
Topic: PIGPIO Stepper Motor Control
Replies: 31
Views: 1158

Re: PIGPIO Stepper Motor Control

pootle wrote:
Thu Nov 05, 2020 7:49 am
However, given the wierd glitchy behaviour mentioned, I think there are other problems here.
Yes, the picture is incomplete.
I'd like to se a video of the "jitter" in action and a circuit diagram and photo of the set-up as well as the things you mention.
by PiGraham
Wed Nov 04, 2020 12:37 pm
Forum: Python
Topic: PIGPIO Stepper Motor Control
Replies: 31
Views: 1158

Re: PIGPIO Stepper Motor Control

For the speed you want waves are a complicated solution. The problem seemed to be that positional control was required and steps were being missed. If that is indeed the case then a software timed pulse train at max speed could be the root of the problem abd it needs a soft start acceleration ramp....
by PiGraham
Tue Nov 03, 2020 12:04 pm
Forum: Beginners
Topic: Auto record 24/7 video in remote area
Replies: 19
Views: 582

Re: Auto record 24/7 video in remote area

4.12. Recording over multiple files
If you wish split your recording over multiple files, you can use the split_recording() method to accomplish this:
https://picamera.readthedocs.io/en/rele ... iple-files
by PiGraham
Mon Nov 02, 2020 4:30 pm
Forum: Python
Topic: LED Visualizer for automatic accoustic piano on python
Replies: 6
Views: 256

Re: LED Visualizer for automatic accoustic piano on python

I begin with an arduino and then my teachers told me to try it with an Raspy since the automatic piano is on raspy Do you mean there is already a RPi working with a keyboard as an automatic piano? If there is already sensors and code to read them and play musical notes it will be very useful to kno...
by PiGraham
Mon Nov 02, 2020 2:31 pm
Forum: Python
Topic: LED Visualizer for automatic accoustic piano on python
Replies: 6
Views: 256

Re: LED Visualizer for automatic accoustic piano on python

How far have you got?
Do you know how to wire to the sensors?
Do you know how to wire to the LEDs?
Can you light the LEDs?
Can you read the key sensors?
Do you know how to read and write gpio pins?
by PiGraham
Mon Nov 02, 2020 8:18 am
Forum: Python
Topic: PIGPIO Stepper Motor Control
Replies: 31
Views: 1158

Re: PIGPIO Stepper Motor Control

Ok so it sounds like waves is the way for me too go. Have you by chance used these waves in pigpio? I ask because the wave example given uses two separate GPIO pins. Is this DIR and PUL, or two PUL's? I haven't used waves myself but I think you can add more than a single gpio to a waveform if you w...
by PiGraham
Sun Nov 01, 2020 9:32 pm
Forum: Python
Topic: PIGPIO Stepper Motor Control
Replies: 31
Views: 1158

Re: PIGPIO Stepper Motor Control

It was recommended I use a level shifter so I do use one. (see my PCB schematic below) Resistors = 1k Transistor = 2N2222A PUL+ and DIR+ to 5v, PUL- and DIR- to transistors (Driver connection at bottom) Do you see any issues? https://imgur.com/WgJCj5l.jpg Do your stepper drivers have input pull-ups...
by PiGraham
Sun Nov 01, 2020 9:28 pm
Forum: Python
Topic: PIGPIO Stepper Motor Control
Replies: 31
Views: 1158

Re: PIGPIO Stepper Motor Control

Method of movement isn't important, so lets just say constant speed. Speed is also not very important, less say 15-30 RPM would be best. Its a significant question because speed control can be done by a continuous stream of pulses at suitable rate but position control requires exact numbers of puls...
by PiGraham
Sun Nov 01, 2020 3:24 pm
Forum: Python
Topic: PIGPIO Stepper Motor Control
Replies: 31
Views: 1158

Re: PIGPIO Stepper Motor Control

Looking at the datasheet for the driver it says logic high level is 5V-24V. That's (far) too high for a Pi. Are you using a level shifter?
by PiGraham
Sun Nov 01, 2020 3:21 pm
Forum: Python
Topic: PIGPIO Stepper Motor Control
Replies: 31
Views: 1158

Re: PIGPIO Stepper Motor Control

What sort of control are you aiming for? Do you just need to turn at constant speed, move quickly between a few set positions, follow smoothly accelerating motion profiles? How many axes and do they need to be coordinated? You mention jitter which is common with RC servos that have a feedback loop. ...
by PiGraham
Fri Oct 30, 2020 8:25 am
Forum: Beginners
Topic: Rpi 4 - can i connect a passive speaker?
Replies: 7
Views: 273

Re: Rpi 4 - can i connect a passive speaker?

No, you can't get useful volume levels from a bare speaker connected to the audio out on the jack socket. You need amplification.
You can get USB powered computer speakers or some small cheap audio amps that can be powered from the 5V pins on the GPIO header.
by PiGraham
Thu Oct 29, 2020 2:28 pm
Forum: Beginners
Topic: Auto record 24/7 video in remote area
Replies: 19
Views: 582

Re: Auto record 24/7 video in remote area

The drive and the battery are not at the same place. The drive would be in the nest box (6 meters) while the battery pack will be in an outdoor enclosure (3 meters). The battery pack is rather accessible but not the drive. But that doesn't answer the key question: why not put the drive in the same ...
by PiGraham
Thu Oct 29, 2020 11:55 am
Forum: Beginners
Topic: Auto record 24/7 video in remote area
Replies: 19
Views: 582

Re: Auto record 24/7 video in remote area

Now the question would be how do I program the Pi to record with a date and timestamp in the video? Do I use raspivid or python or picamera? Do you have a realtime clock module or other way to keep the time correct? https://www.raspberrypi.org/documentation/raspbian/applications/camera.md --annotat...
by PiGraham
Wed Oct 28, 2020 8:59 pm
Forum: Beginners
Topic: Auto record 24/7 video in remote area
Replies: 19
Views: 582

Re: Auto record 24/7 video in remote area

The drive and the battery are not at the same place. The drive would be in the nest box (6 meters) while the battery pack will be in an outdoor enclosure (3 meters). The battery pack is rather accessible but not the drive. But that doesn't answer the key question: why not put the drive in the same ...
by PiGraham
Wed Oct 28, 2020 4:22 pm
Forum: Beginners
Topic: Auto record 24/7 video in remote area
Replies: 19
Views: 582

Re: Auto record 24/7 video in remote area

1. Needs to record continues video for 24/7 and save into 1 TB external drive. 2. Should auto record every time the battery pack is change (approximate every week). Why can't you swap the drive when you change the battery? That was a good suggestion. It will be by far the quickest way to extract 21...
by PiGraham
Tue Oct 27, 2020 11:46 am
Forum: Off topic discussion
Topic: Kind of hard to do with a Pi...
Replies: 148
Views: 9094

Re: Kind of hard to do with a Pi...

Since at any given time 95 percent of cars are parked, the batteries in electric vehicles could be used to let electricity flow from the car to the electric distribution network and back. A 2015 report on potential earnings associated with V2G found that with proper regulatory support, vehicle owne...
by PiGraham
Tue Oct 27, 2020 9:52 am
Forum: Off topic discussion
Topic: Kind of hard to do with a Pi...
Replies: 148
Views: 9094

Re: Kind of hard to do with a Pi...

FTrevorGowen wrote:
Tue Oct 27, 2020 9:18 am
it was decided to feed the electric cables through the gas pipes.

Ah, I see. Use gas pipes as conduits for new electrical cabling to save some trenching.

But won't we need those pipes for a hydrogen grid?
by PiGraham
Tue Oct 27, 2020 9:48 am
Forum: Off topic discussion
Topic: Kind of hard to do with a Pi...
Replies: 148
Views: 9094

Re: Kind of hard to do with a Pi...

A better route, if there is lack of room, is use the gas pipes, they're large, all pretty new now (at least around this area of the country) and a fossil fuel set to go and not even connected to new housing. (soon) How would that work? Is some gas pipeline electrically insulated for the 2.4 kV and ...
by PiGraham
Mon Oct 26, 2020 9:26 pm
Forum: Off topic discussion
Topic: Kind of hard to do with a Pi...
Replies: 148
Views: 9094

Re: Kind of hard to do with a Pi...

"Probably"? You can't possibly store or pump hydrogen as if it was petroleum. It needs extremely high pressure systems. 350 bar. Only if you want it to be stored in liquid form. We can store some of it the same way as we store natural gas these days, under high pressure in the pipelines (up to abou...
by PiGraham
Mon Oct 26, 2020 9:18 pm
Forum: Off topic discussion
Topic: Kind of hard to do with a Pi...
Replies: 148
Views: 9094

Re: Kind of hard to do with a Pi...

Road to zero The government has confirmed its ambition to see at least half of new cars to be ultra low emission by 2030 as part of plans to make the UK the best place in the world to build and own an electric vehicle. The proposals are outlined in the Road to Zero Strategy, which sets out plans to...
by PiGraham
Mon Oct 26, 2020 9:12 pm
Forum: Off topic discussion
Topic: Kind of hard to do with a Pi...
Replies: 148
Views: 9094

Re: Kind of hard to do with a Pi...

2. Ban private cars. Replace them with cheap to use, readily available, self driving EVs. Can't see either of those catching on though. Too much vested interest in the status quo and to much me first before the benefit to society. That is the current plan : The UK is poised to bring forward its ban...
by PiGraham
Mon Oct 26, 2020 6:18 pm
Forum: Off topic discussion
Topic: Kind of hard to do with a Pi...
Replies: 148
Views: 9094

Re: Kind of hard to do with a Pi...

We have 11 stations in the UK c.f. 11,000 34,000+ locations for EV charging stations https://www.edfenergy.com/electric-cars/charging-points That might have something to do with the challenges of deploying hydrogen. FTFY, you're welcome. more than 30,000 charge points across the UK in over 11,000 l...
by PiGraham
Mon Oct 26, 2020 5:43 pm
Forum: Off topic discussion
Topic: Kind of hard to do with a Pi...
Replies: 148
Views: 9094

Re: Kind of hard to do with a Pi...

One suggestion I have not seen is to standardise the batteries and make them easily swapable. Then when you are running low you pull in to a service station, swap out your old battery for a fully charged one. Probably just as quick as filling up with liquid fuel. The batteries would probably have a...
by PiGraham
Mon Oct 26, 2020 5:26 pm
Forum: Off topic discussion
Topic: Kind of hard to do with a Pi...
Replies: 148
Views: 9094

Re: Kind of hard to do with a Pi...

Use the existing infrastructure we have for petrol, diesel and LPG. Probably have to change the pumps and storage tanks but you won't need to upgrades the grid and find ways for people without private parking to plug in their cars. "Probably"? You can't possibly store or pump hydrogen as if it was ...
by PiGraham
Mon Oct 26, 2020 5:20 pm
Forum: Off topic discussion
Topic: Kind of hard to do with a Pi...
Replies: 148
Views: 9094

Re: Kind of hard to do with a Pi...

wind & solar need storage. EVs have storage. Use them to crack water and capture the Hydrogen, unless you've got local terrain that will permit a pumped water system (pump it up high with the excess wind/solar, run it back down through a turbine when you need more power). Most places don't have the...

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