Go to advanced search

by PiGraham
Thu Oct 17, 2019 9:38 am
Forum: Advanced users
Topic: Run and Stop a stepper motor
Replies: 7
Views: 659

Re: Run and Stop a stepper motor

You could also do the stepping in a timer callback and start or stop the timer from your main program loop. You could change the stepping rate be altering the timer value and you could change direction by setting variables in the main loop that the timer callback will use to control step sequence.
by PiGraham
Mon Oct 14, 2019 10:34 am
Forum: Beginners
Topic: A relay turns a light on/off, how to detect a burnt light ? [solved]
Replies: 40
Views: 1929

Re: A relay turns a light on/off, how to detect a burnt light ?

Thanks Jamesh and PiGraham it is good to know that not all forum members thing the same about that "issue". I am a bit more relaxed now :) The initial question was also meant to be simplified as much as possible (not for deceiving purposes): "A relay turns a light on/off, how to detect a burnt ligh...
by PiGraham
Mon Oct 14, 2019 9:55 am
Forum: Beginners
Topic: A relay turns a light on/off, how to detect a burnt light ? [solved]
Replies: 40
Views: 1929

Re: A relay turns a light on/off, how to detect a burnt light ?

If you don't want to give them advice, fine, but do not complain about it. I'd like to apologise to the OP, who has got some negative answers for no reason that I can see. Most who post here do want to give advice, obviously. I suspect some would be prepared to put extra effort into helping kids wi...
by PiGraham
Mon Oct 14, 2019 9:42 am
Forum: Beginners
Topic: A relay turns a light on/off, how to detect a burnt light ? [solved]
Replies: 40
Views: 1929

Re: A relay turns a light on/off, how to detect a burnt light ?

OK, I'll add my own apology to adrianTNT.

I don't have a problem with people asking questions for commercial projects.

I will stand by this that I think applies to lots of posts:

Your best chance of receiving advice fit for purpose is to be clear about the purpose.
by PiGraham
Sun Oct 13, 2019 9:04 pm
Forum: Beginners
Topic: A relay turns a light on/off, how to detect a burnt light ? [solved]
Replies: 40
Views: 1929

Re: A relay turns a light on/off, how to detect a burnt light ?

You could just have been up-front about it and say your relative is a reseller of street lighting systems and you have been asked to look into a low cost lamp monitoring system possibly using Raspberry Pi. Then there are no surprises. If there happens to be an engineer in the forum that is knowledge...
by PiGraham
Sun Oct 13, 2019 7:48 pm
Forum: Beginners
Topic: A relay turns a light on/off, how to detect a burnt light ? [solved]
Replies: 40
Views: 1929

Re: A relay turns a light on/off, how to detect a burnt light ?

You really don't need to have a GPS in each lamp since they never move. You'd be surprised … not that they move, but a whole lot of fixed lighting infrastructure has a GPS in every unit: a GPS + a simple microcontroller gives you exact civil twilight times. Some places have legal requirements that ...
by PiGraham
Sun Oct 13, 2019 3:09 pm
Forum: Beginners
Topic: A relay turns a light on/off, how to detect a burnt light ? [solved]
Replies: 40
Views: 1929

Re: A relay turns a light on/off, how to detect a burnt light ?

You are using the forum to do the research for you I hope you will donate your fee to charity, You should Have said in the first place you are doing it for a Re-seller, be fair give us the name of the re-seller You are working for, so we can tell them It is not. Your idea Regards BoyOh Anyone else ...
by PiGraham
Sun Oct 13, 2019 8:34 am
Forum: Beginners
Topic: A relay turns a light on/off, how to detect a burnt light ? [solved]
Replies: 40
Views: 1929

Re: A relay turns a light on/off, how to detect a burnt light ?

adrianTNT wrote:
Sun Oct 13, 2019 7:48 am
The goal is to incorporate the solution in a new lamp (not the existent different models), so they should be all the same.
In that case why not use lamps which have this monitoring function integrated ?
Are you working for a streetlamp manufacturer?
by PiGraham
Sun Oct 13, 2019 7:28 am
Forum: Beginners
Topic: A relay turns a light on/off, how to detect a burnt light ? [solved]
Replies: 40
Views: 1929

Re: A relay turns a light on/off, how to detect a burnt light ?

LDR could be a problem to install. Ideally it would be inside the lamp housing to protect it from dirt, weather and extraneous light. That would presumably require an elevated platform to fit it A current measuring option could be installed at ground level. I don't think it would be difficult to det...
by PiGraham
Sat Oct 12, 2019 12:17 pm
Forum: General discussion
Topic: quest for a nice compact keyboard ?
Replies: 11
Views: 697

Re: quest for a nice compact keyboard ?

There is a requirements conflict between "nice" and "compact". Compact keyboards are, generally, not nice and nice keyboards are, generally, not compact. If you like the retro feel of ZX Spectrum dead-men's fingers https://www.amazon.co.uk/Flexible-Foldable-Portable-Silicone-Keyboard/dp/B005AILVFK ...
by PiGraham
Fri Oct 11, 2019 7:12 am
Forum: General discussion
Topic: quest for a nice compact keyboard ?
Replies: 11
Views: 697

Re: quest for a nice compact keyboard ?

any suggestions ? https://www.raspberrypi.org/blog/official-raspberry-pi-keyboard-mouse/ If target size is 150 x 50mm the official keyboard is much too big at ~ 280 x 120 mm All the very small keyboards I have seen are wireless. This one from Pimoroni is smaller yet at 115mm x 60mm x 8.6mm (4.5" x ...
by PiGraham
Thu Oct 10, 2019 2:28 pm
Forum: Beginners
Topic: A relay turns a light on/off, how to detect a burnt light ? [solved]
Replies: 40
Views: 1929

Re: A relay turns a light on/off, how to detect a burnt light ?

You really don't need to have a GPS in each lamp since they never move. Put a unique ID code on each one and stand with your phone by each lamp post in turn and drop a pin on Google maps named by that ID. The installer can easily do that as part of the job. Your county council (and mine) already ha...
by PiGraham
Thu Oct 10, 2019 1:31 pm
Forum: General discussion
Topic: Detect HDMI Split
Replies: 13
Views: 626

Re: Detect HDMI Split

A simple check would be to use the EDID conditionals in config.txt to make the system non-bootable should it not have the correct monitor name connected (config.txt parsing can't do EDID serial number). An application could parse the EDID to check the serial number too. NB This is defining a whitel...
by PiGraham
Thu Oct 10, 2019 1:24 pm
Forum: Beginners
Topic: A relay turns a light on/off, how to detect a burnt light ? [solved]
Replies: 40
Views: 1929

Re: A relay turns a light on/off, how to detect a burnt light ?

I plan to make a web server that will control lamps on/off or set schedules, and the individual lamps will be with relays, nRF24L01 or similar wireless transceiver, and GPS sensor so the bad lamps can be seen on map. You really don't need to have a GPS in each lamp since they never move. Put a uniq...
by PiGraham
Thu Oct 10, 2019 12:31 pm
Forum: Beginners
Topic: A relay turns a light on/off, how to detect a burnt light ? [solved]
Replies: 40
Views: 1929

Re: A relay turns a light on/off, how to detect a burnt light ?

These are estimates that are not very accurate but: out of 500 lamps maybe 10-20 can fail over a year, not inspected regularly but people report them to city hall if nearby light doesn't work for 3-5 days, and fixed in 3-7 days after reported in a way. So sensors would help, the above solution seem...
by PiGraham
Thu Oct 10, 2019 9:12 am
Forum: Beginners
Topic: A relay turns a light on/off, how to detect a burnt light ? [solved]
Replies: 40
Views: 1929

Re: A relay turns a light on/off, how to detect a burnt light ?

You could use an inductive clamp type sensor. https://www.poweruc.pl/blogs/news/non-invasive-sensor-yhdc-sct013-000-ct-used-with-arduino-sct-013?gclid=Cj0KCQjwrfvsBRD7ARIsAKuDvMMxmSmarPgxvu3yBEOJjuxLuiUYmZFYZMiaXITFeOzOtNXdU-bOFDwaAveKEALw_wcB https://www.seeedstudio.com/Non-invasive-AC-Current-Sens...
by PiGraham
Tue Oct 08, 2019 9:36 am
Forum: General discussion
Topic: Detect HDMI Split
Replies: 13
Views: 626

Re: Detect HDMI Split

- You have to be able to read the EDIDs from the multiple displays and combine them so that the source knows the set of modes supported by all displays. How about locking the application to a specific EDID? If you can get the serial number of the display from the EDID data maybe you could use that ...
by PiGraham
Sun Oct 06, 2019 1:12 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Safe to connect 2 Pis to same SPI chip?
Replies: 7
Views: 758

Re: Safe to connect 2 Pis to same SPI chip?

The problem is that both your Pi's must know whether one is asking to use the bus or not. So you'd have to wire the chip select signal to both. That is exactly why it's a non-starter. There's no way to serialise access between each Raspberry because SPI isn't designed as a loosely coupled shared in...
by PiGraham
Sat Oct 05, 2019 11:22 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Safe to connect 2 Pis to same SPI chip?
Replies: 7
Views: 758

Re: Safe to connect 2 Pis to same SPI chip?

It you don't like the gadget mode option why not use the UARTs? I think that would be much simpler. I doubt you could connect one SPI slave to two SPI masters since that would be connecting two masters together. It might be possible if you has a way to reliably tristate (configure as input) one mast...
by PiGraham
Tue Oct 01, 2019 4:12 pm
Forum: General discussion
Topic: Wirebender with a Raspberry PI and PiGPIO
Replies: 19
Views: 705

Re: Wirebender with a Raspberry PI and PiGPIO

If you want to move something a precise amount against the force required to bend wire I would recommend using servos. Steppers are good for all sorts of things but they have no indies where they are at any time. Servos can be commanded to a particular position rather than “move 6 steps”, which can...
by PiGraham
Tue Oct 01, 2019 4:04 pm
Forum: General discussion
Topic: Wirebender with a Raspberry PI and PiGPIO
Replies: 19
Views: 705

Re: Wirebender with a Raspberry PI and PiGPIO

Do you think that the motor is not strong enough for that task? I could work in some transmission for the bending, too. I don't know. You can copy something that works or you can measure an calculate. If you have a weighing scale and lever bar to turn your bending jaws you can get the torque by mul...
by PiGraham
Tue Oct 01, 2019 3:18 pm
Forum: General discussion
Topic: Wirebender with a Raspberry PI and PiGPIO
Replies: 19
Views: 705

Re: Wirebender with a Raspberry PI and PiGPIO

Also he creates ramps in PiGPIO which would be useful, and shows in the video a stepper motor connected to a dvr 8825 connected to a raspberry pi running the PIGPIO script. I just would like to understand :( If you need high speed and rapid changes of direction then ramping step rates up and down c...
by PiGraham
Tue Oct 01, 2019 2:28 pm
Forum: General discussion
Topic: Wirebender with a Raspberry PI and PiGPIO
Replies: 19
Views: 705

Re: Wirebender with a Raspberry PI

If you use a stepper driver board you send it a direction signal and a sequence of pulses and the motor should wove one step (or micro-step) per pulse. The timing of the step pulse isn't critical and you can do it in a software loop setting a gpio output alternately high and low with a short delay b...
by PiGraham
Fri Sep 27, 2019 2:48 pm
Forum: Automation, sensing and robotics
Topic: Raspi to press the button automatically
Replies: 5
Views: 466

Re: Raspi to press the button automatically

gordon77 wrote:
Thu Sep 26, 2019 8:42 am

That looks a neat device, anyone got one to work with a Pi ?
Apparently it is possible:

https://www.switch-bot.com/forum/annouc ... spberry-pi
https://github.com/OpenWonderLabs/python-host
by PiGraham
Thu Sep 26, 2019 8:27 am
Forum: Automation, sensing and robotics
Topic: Raspi to press the button automatically
Replies: 5
Views: 466

Re: Raspi to press the button automatically

Does anyone have any idea what would be the best way to get the Raspberry pi to press a button every 30 minutes. Is it possible to make that cirquit without relay or transistor? You can control a servo direct form a GPIO pin and that could physically press a button. Another thread: https://www.rasp...

Go to advanced search