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by stevend
Wed Nov 24, 2021 10:09 pm
Forum: General discussion
Topic: Will you make microchips like RP2040, but with leads (QFP)?
Replies: 19
Views: 655

Re: Will you make microchips like RP2040, but with leads (QFP)?

Some interesting comments here, much of which I do already on some boards (e.g. use of pre-made processor modules). The thread was obviously about the Pico; my comments were intended to be a bit more general. So far I haven't had a project where a Pico is appropriate; when that becomes a possibility...
by stevend
Wed Nov 24, 2021 4:36 pm
Forum: General discussion
Topic: Will you make microchips like RP2040, but with leads (QFP)?
Replies: 19
Views: 655

Re: Will you make microchips like RP2040, but with leads (QFP)?

The problem is size - it would be a very large package to get all the pins in. Same with doing it in DIL. It's been discussed over the lunch table, but nothing more than that. Size isn't everything! In my own case, I generally have space to spare. We often do small runs of boards (1-10) so I try to...
by stevend
Fri Nov 19, 2021 6:20 pm
Forum: General discussion
Topic: How to connect a 12V Anemometer to a MCP3008 with Raspberry Pi
Replies: 6
Views: 223

Re: How to connect a 12V Anemometer to a MCP3008 with Raspberry Pi

I'm trying to read the data from a 12 V anemometer to my raspberry pi model 4B using the MCP3008 analog to digital converter. However, I'm confused on how to connect the wires in a correct manner. Can anyone show me the correct connection diagram ? I'm using a 12 V adapter in addition. Does your an...
by stevend
Thu Nov 11, 2021 2:16 pm
Forum: General discussion
Topic: Pi Back Up Battery UPS
Replies: 3
Views: 207

Re: Pi Back Up Battery UPS

Everytime I've researched this, I've always reached the same conclusion - that it is easier/cheaper/better to use a AC line UPS, rather than try to power the Pi directly from batteries. Have you considered the energy efficiency of a UPS in this mode? A UPS comprises essentially a float-charged lead...
by stevend
Wed Nov 10, 2021 5:43 pm
Forum: General
Topic: UCSD Pascal on the Pico
Replies: 5
Views: 338

Re: UCSD Pascal on the Pico

Despite it's evident demise Pascal still holds a special place for me! It was the first language I encountered to introduce strong typing, data and procedural scope with nesting in a relatively small and elegant package. That along with the introduction of Turbo Pascal compiler for the IBM PC was v...
by stevend
Wed Nov 10, 2021 5:37 pm
Forum: Off topic discussion
Topic: Power supply from 42V DC to 5V DC
Replies: 15
Views: 831

Re: Power supply from 42V DC to 5V DC

Like I mentioned above a string of 1n4007 can help. A little power wasted but nowhere near as much as linear regulator or transistor used to drop all the way. If efficiency is more important than cost, a "perfect diode" or "ideal diode" is a good solution. Basically a high curre...
by stevend
Wed Nov 10, 2021 1:38 pm
Forum: General
Topic: UCSD Pascal on the Pico
Replies: 5
Views: 338

Re: UCSD Pascal on the Pico

Now that's a blast from the past! In the late 70s Western Digital produced the 'Pascal Microengine' by modifying the microcode on a chip set used for one of the early DEC computers (possibly PDP-11) so that it directly executed P-code, bypassing the small run-time interpreter needed for other platfo...
by stevend
Thu Nov 04, 2021 1:27 pm
Forum: Other projects
Topic: Boating Uses For a RPi
Replies: 4
Views: 288

Re: Boating Uses For a RPi

I installed OpenCPN and CubicSDR with Nooelec NESDR Smart v4 SDR (radio). Since I am knowledgeable about radios, I am concentrating on the SDR. My basic RTL SDR is pretty lousy as a radio for receiving. I am considering building a preamp bandpass filter with one or more op amps, and wonder if anyon...
by stevend
Wed Nov 03, 2021 1:34 pm
Forum: Compute Module
Topic: Use uart3 to send and receive date via a rs485 module
Replies: 8
Views: 384

Re: Use uart3 to send and receive data via a rs485 module

Thank you for your reply.I think I have a idea of fixing this problem. I use the GPIO7 to replace the GPIO25. And then set GPIO7 function to alt4.So it's RTS3 now. The default level of RTS3 is high. and when UART3 is sending data.RTS3 is low. When GPIO7 is connect to TP485E. if CM4 want to send dat...
by stevend
Tue Nov 02, 2021 1:08 pm
Forum: Compute Module
Topic: Use uart3 to send and receive date via a rs485 module
Replies: 8
Views: 384

Re: Use uart3 to send and receive date via a rs485 module

Don't think the standard kernel supports RS-485 mode on the pl011 UARTs used on the pi - see this thread.
You might need to roll your own kernel, as danjperron suggests.
by stevend
Fri Oct 29, 2021 8:13 pm
Forum: Other projects
Topic: Boating Uses For a RPi
Replies: 4
Views: 288

Re: Boating Uses For a RPi

Have a look at OpenCPN; or, if you want more already done for you, OpenPlotter.
by stevend
Tue Oct 26, 2021 7:19 pm
Forum: SDK
Topic: volatile const
Replies: 20
Views: 736

Re: volatile const

Could you buffer the new base values temporarily, then have a mechanism which does the update when both cores are at a particular point? (It could be as simple as setting a byte when an update is available; both cores periodically test this flag, when both are ready one core waits and the other does...
by stevend
Tue Oct 26, 2021 7:14 pm
Forum: Automation, sensing and robotics
Topic: Connecting Serial Flowmeter TSI 5200 Series to Rpi 4
Replies: 3
Views: 243

Re: Connecting Serial Flowmeter TSI 5200 Series to Rpi 4

What about the FTDI chip would allow it to work with the Pi compared to the Prolific? Or is my cable not actually the problem? The two chips require different commands to make them work. (That's why they need different drivers on the average PC; the FTDI driver is often included with the OS, but I'...
by stevend
Mon Oct 25, 2021 9:16 pm
Forum: Other projects
Topic: Having a long (10-20m) LED strip powered by a Raspberry Pi?
Replies: 8
Views: 547

Re: Having a long (10-20m) LED strip powered by a Raspberry Pi?

Incidentally, when you're assessing brightness, you'll need to take account of any diffuser you use. Can't find the reference at present, but from memory an opal diffuser can reduce the light output by 50%. A clear by around 10%, frosted by 20-25%.

The installation I mentioned used an opal diffuser.
by stevend
Mon Oct 25, 2021 12:20 pm
Forum: Other projects
Topic: Having a long (10-20m) LED strip powered by a Raspberry Pi?
Replies: 8
Views: 547

Re: Having a long (10-20m) LED strip powered by a Raspberry Pi?

Okay, thanks! What is the exact name for the current buffers? Just to make sure that I understand it correctly and don't forget to buy it... Probably something like "logic level MOSFET", but best to search the forum for people who have actually driven RGB LED strips. Note that there are t...
by stevend
Sun Oct 24, 2021 10:25 pm
Forum: Other projects
Topic: Having a long (10-20m) LED strip powered by a Raspberry Pi?
Replies: 8
Views: 547

Re: Having a long (10-20m) LED strip powered by a Raspberry Pi?

I want to have RGB, because it looks nicer and I might want to append a temperature sensor and by speech detection you can then ask for the temperature, and it will give an answer via a speaker and also shine in a blue color if it's cold or in a red color if it's warm. Or something like that... Fai...
by stevend
Sat Oct 23, 2021 9:47 pm
Forum: Other projects
Topic: Having a long (10-20m) LED strip powered by a Raspberry Pi?
Replies: 8
Views: 547

Re: Having a long (10-20m) LED strip powered by a Raspberry Pi?

It seems to me that you only need a single colour LED strip with a simple on/off control for your application; some of my comments probably won't apply if you go for multi-colour LEDs. I wanted to have some initial suggestions in a German Raspberry Pi forum, but they told me that I should rather get...
by stevend
Fri Oct 22, 2021 5:27 pm
Forum: Automation, sensing and robotics
Topic: Incorrect readings with HC-SR04 at short distance
Replies: 7
Views: 351

Re: Incorrect readings with HC-SR04 at short distance

I'm using the version with a single ultrasonic device (because I need it to be reasonably waterproof). I've had encouraging results directing the sensor down a 25mm diameter tube which goes to the bottom of the tank; hope to test in anger over the next few weeks. The downside of a single transceiver...
by stevend
Fri Oct 22, 2021 5:22 pm
Forum: General discussion
Topic: GPSD users: Time travel bug hitting this weekend
Replies: 32
Views: 1237

Re: GPSD users: Time travel bug hitting this weekend

Depends on how you use GPSD. From: https://www.theregister.com/2021/10/19/gpsd_bug_reset/ "Depending on what GPS/GNSS receiver is in use, and how it is configured, the chance is either 0 per cent or 100 per cent. Devices configured to output 'Standard' NMEA, will not be affected. Devices, like ...
by stevend
Thu Oct 21, 2021 7:45 pm
Forum: Off topic discussion
Topic: Price increase by +50%?
Replies: 25
Views: 1827

Re: Price increase by +50%?

If you guys notice, in my country the biggest percentage of price difference (from the Official Price) is for the cheapest, USD 35 model . However, the price (including tax) is okay for the 4GB model, which is at MYR 249 @ USD 59.93, per the link below. Do bear in mind that the tax works the same w...
by stevend
Mon Oct 18, 2021 7:28 pm
Forum: General discussion
Topic: Do we love the 40-pin header? Is there something more desireable?
Replies: 33
Views: 1467

Re: Do we love the 40-pin header? Is there something more desireable?

An IDE cable will fit the full header allowing for re-use of old cables DO NOT use IDE cables with your Raspberry PI, that will kill it. IDE cables have several wires shorted together by design inside them. I posted about how stupid that design was a long time ago. i personnally thing that was Stup...
by stevend
Mon Oct 18, 2021 7:23 pm
Forum: General discussion
Topic: Two-way data transfer between Pi's over a very long cable
Replies: 53
Views: 2667

Re: Two-way data transfer between Pi's over a very long cable

Thank you for that clarification. I am not entirely sure what is the connector on these converters that I linked earlier - the specs don't say, it looks like this: https://i.imgur.com/sOtPouP.png I checked your links, and the connector in the pic sort of looks like BNC. Definitely BNC. You can usua...
by stevend
Sun Oct 17, 2021 2:33 pm
Forum: General discussion
Topic: Two-way data transfer between Pi's over a very long cable
Replies: 53
Views: 2667

Re: Two-way data transfer between Pi's over a very long cable

One more question - it may be trivial but I just want to make sure - if the media converter is meant for RG-59, and accepts RG-59 connector, what would be the best way to connect RG-179 (or a similar 75 ohm coax) to it? The way coax connectors are crimped, doesn't look to me that a RG-59 connector ...
by stevend
Sun Oct 17, 2021 8:25 am
Forum: General discussion
Topic: Two-way data transfer between Pi's over a very long cable
Replies: 53
Views: 2667

Re: Two-way data transfer between Pi's over a very long cable

All of these modules seem to be meant for RG59, which is a very thick coax. Would it be possible to use something like RG174 for this? Would these modules work with it? All coaxial cable has a 'characteristic impedance'; for 'Standard' (or 'popular') coaxial cables this is either 50 ohm or 75 ohm. ...
by stevend
Fri Oct 15, 2021 5:25 pm
Forum: General discussion
Topic: Two-way data transfer between Pi's over a very long cable
Replies: 53
Views: 2667

Re: Two-way data transfer between Pi's over a very long cable

Option 1 : regular ethernet (CAT5) cable with RJ45 connectors on both ends, plugged in directly to RPI on the sub, and to another RPI (or a wireless modem) on the surface. Pros: seems to be the most common option for simultaneous two-way data communication, fast enough for video feed too. Reasonabl...

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