Go to advanced search

by JohnsUPS
Wed May 15, 2019 1:18 am
Forum: Automation, sensing and robotics
Topic: My temp sensor ds18b20 doesn't seems accurate
Replies: 14
Views: 338

Re: My temp sensor ds18b20 doesn't seems accurate

I have had this happen to me also. Where were the sensors purchased? I have about 30 of these sensors. 10 each were purchased from three different vendors. Two of the vendors were of Chinese origin, and the other was Mouser. After the first order of 10, I realized they were not calibrated because th...
by JohnsUPS
Wed May 08, 2019 5:25 pm
Forum: Beginners
Topic: Will a power supply with a higher amp-age work with the pi?
Replies: 22
Views: 14041

Re: Will a power supply with a higher amp-age work with the pi?

It is like the ampere-hour capacity of a battery and is not applicable to the discussion in this thread. I agree, that is more correct. Reservoir was probably not the best choice of words. Current sourcing capability. I also agree about the water flow analogy being useful, but only to a point. I ge...
by JohnsUPS
Wed May 08, 2019 10:29 am
Forum: Beginners
Topic: Will a power supply with a higher amp-age work with the pi?
Replies: 22
Views: 14041

Re: Will a power supply with a higher amp-age work with the pi?

A lot of that is incorrect. The size of the reservoir is not the "amperage capability". The current is not the "actual water" but the rate of flow of the water. I respectfully disagree. Note that I said "as it applies to this discussion". Sure, electrons (or holes, depending on the theory you subsc...
by JohnsUPS
Wed May 08, 2019 12:39 am
Forum: Beginners
Topic: Will a power supply with a higher amp-age work with the pi?
Replies: 22
Views: 14041

Re: Will a power supply with a higher amp-age work with the pi?

Another way to look at the electricity and water comparison is this: Voltage is the water pressure produced by a water pump. Amperage capability (as it applies in this discussion) is the size of the reservoir that feeds the water pipe. Currrent is the actual water. Resistance is related to the diame...
by JohnsUPS
Sun May 05, 2019 1:17 am
Forum: General discussion
Topic: Raspberry Pi Zero W.....for a pub
Replies: 6
Views: 293

Re: Raspberry Pi Zero W.....for a pub

If your pub has the need for cold food storage, then the Pi could be used to periodically take temperature readings to satisfy the inspectors. This is more mechanical, but a machine that could tip a bottle and pour a shot would make for interesting conversation. A reaction timer.....light (LED or wh...
by JohnsUPS
Sat May 04, 2019 5:07 am
Forum: Automation, sensing and robotics
Topic: Pressure logging project
Replies: 6
Views: 255

Re: Pressure logging project

If you go with the 625 transducer with the 4 - 20ma output, it is to your advantage that it has a current source output. Current outputs are inherently less noisy and can run fair distances in an electrically noisy environment. This is good, especially if you're connecting it to an ADC. You can easi...
by JohnsUPS
Thu May 02, 2019 1:51 pm
Forum: HATs and other add-ons
Topic: Sensors maximum length
Replies: 6
Views: 272

Re: Sensors maximum length

When it comes to the DS18B20 temperature sensors with regards to wiring length, you may want to check this thread:
viewtopic.php?t=36163
by JohnsUPS
Sat Apr 27, 2019 11:45 pm
Forum: Advanced users
Topic: Seeking the illusive zero write
Replies: 14
Views: 639

Re: Seeking the illusive zero write

Have you considered a different storage medium such as a SSD? Size and/or power consumption may be an issue though...
by JohnsUPS
Sat Apr 27, 2019 2:32 am
Forum: General discussion
Topic: Will Arduino nano and RPI get Damaged on Supplying 5V 3A DC?
Replies: 29
Views: 740

Re: Will Arduino nano and RPI get Damaged on Supplying 5V 3A DC?

As achrn said: I have lots of power supplies that I didn't make. I wouldn't make a power supply now (though I have made linear supplies in the past) because switched mode units are now so plentiful and it makes much more sense just to buy one than build one. ......and this is the case with the 4A po...
by JohnsUPS
Fri Apr 26, 2019 11:16 am
Forum: General discussion
Topic: Will Arduino nano and RPI get Damaged on Supplying 5V 3A DC?
Replies: 29
Views: 740

Re: Will Arduino nano and RPI get Damaged on Supplying 5V 3A DC?

You can use a single power supply for both of them, so long as the voltage is correct (you stated 5.1v) and the current sourcing capability of your power supply is greater than what both boards will be demanding. To me, a 3A supply will probably be OK for both boards, but just for the boards only. I...
by JohnsUPS
Wed Apr 24, 2019 3:06 am
Forum: Automation, sensing and robotics
Topic: Voltage Datalogger (please help out a noob)
Replies: 6
Views: 367

Re: Voltage Datalogger (please help out a noob)

Fuzzy, With the previous warnings about working with mains voltages presumably heeded, there is a standard way that overhead mains are typically monitored. The voltages are stepped down using precision ratio transformers (PT's), and precision ratio current transformers (CT's). The scaling of the PTs...
by JohnsUPS
Wed Apr 24, 2019 2:32 am
Forum: Automation, sensing and robotics
Topic: Help with analog inputs, 0-5V sensors
Replies: 3
Views: 193

Re: Help with analog inputs, 0-5V sensors

Arch, Because you are interested in a span of the analog output and not just a trip point, then yes, you're going to need some sort of ADC between your sensor and the Pi. The ADC PiZero addon board looks like it would work. It provides eight analog inputs, so you'll have room for expansion if necess...
by JohnsUPS
Sun Apr 21, 2019 12:23 am
Forum: Automation, sensing and robotics
Topic: Help with analog inputs, 0-5V sensors
Replies: 3
Views: 193

Re: Help with analog inputs, 0-5V sensors

In the case of the pressure transducer, consider how it is to be used. For example, if you want to have different things happen when the pressure transducer is seeing different pressures (like how much air pressure is in a tank and you want a variable readout of the pressure), then you'd probably wa...
by JohnsUPS
Tue Apr 16, 2019 12:24 pm
Forum: General discussion
Topic: Powering RPI 3B+ With 24VAC
Replies: 17
Views: 619

Re: Powering RPI 3B+ With 24VAC

You also want to keep in mind that in addition to powering the Pi, this power supply will also be actuating solenoids to control water flow. When a (or multiple) solenoids are actuated, there is the possibility of the supply voltage being dragged down, which may interrupt the Pi. Just be aware that ...
by JohnsUPS
Mon Apr 15, 2019 1:15 pm
Forum: Automation, sensing and robotics
Topic: CT Sensor not working on home AC Feed
Replies: 5
Views: 213

Re: CT Sensor not working on home AC Feed

Hi all, I've been working on getting a CT sensor to work for a couple of weeks now. I've been doing my testing with a standard 13A kettle lead and have separated the live, neutral and earth - putting the clamp around the live wire. This has worked fine and I've got some accurate, calibrated reading...
by JohnsUPS
Mon Apr 15, 2019 1:59 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: interface with digital calipers
Replies: 52
Views: 8865

Re: interface with digital calipers

I like the look of that. An RPI with a big monitor and some extra functionality like relative positions etc would finish it off .. Oh and maybe a box or tow but then half my stuff never actually makes it in to a proper housing... In the finished Arduino version, there are buttons to set each calipe...
by JohnsUPS
Sat Apr 13, 2019 11:09 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: interface with digital calipers
Replies: 52
Views: 8865

Re: interface with digital calipers

OK....now I'm just going to have to do this with a Pi. Besides an electronics workshop, I also have a small machine shop. I affixed calipers to my mill and one of the lathes. The great thing about this is that there is zero backlash. Of course I wanted remote displays, so I used an Arduino. I should...
by JohnsUPS
Thu Apr 11, 2019 1:09 pm
Forum: Automation, sensing and robotics
Topic: DS18B20 network issues after 2 months stable
Replies: 5
Views: 254

Re: DS18B20 network issues after 2 months stable

I would advise against a loop of any sort. Instead, consider stringing them all out along a single length of cable. You're showing ~58m of cable, which should not pose a problem if wired correctly. Consider wiring in a small capacitor at each sensor to see if that improves anything.
by JohnsUPS
Wed Apr 10, 2019 11:52 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Detecting AC current using DC transformer
Replies: 4
Views: 356

Re: Detecting AC current using DC transformer

I need to monitor a float in a water tank. The float acts as a switch in a 120V AC circuit; when the water level falls below a specified level, the float switch closes and activates a contactor (relay) in the pump house that turns the well pump on. When the water level rises above a set level, it s...
by JohnsUPS
Mon Apr 08, 2019 11:06 pm
Forum: Off topic discussion
Topic: Learning Electronics
Replies: 56
Views: 2477

Re: Learning Electronics

Do try to keep up though. TAOE is now on it's 3rd edition: https://artofelectronics.net/ Oops....I was thinking the silver edition was the first....should have looked behind me on the shelf and checked the revision #. I bought the third edition as soon as I saw it.... I think most people only make ...
by JohnsUPS
Mon Apr 08, 2019 10:26 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: DS18B20 Max Distance
Replies: 41
Views: 42310

Re: DS18B20 Max Distance

Frank, I'm sure that a Pi could be configured to set the outputs to a known state upon booting up. If the sprinkler valves are solenoid operated, I suspect (correct me if I'm wrong) they would shut off by default upon a power loss. Also upon booting, you could have the Pi run a routine to take inven...
by JohnsUPS
Mon Apr 08, 2019 1:30 am
Forum: Automation, sensing and robotics
Topic: Wiring relay to Pi
Replies: 27
Views: 1038

Re: Wiring relay to Pi

Consider a different opto.
My go-to opto is the MCT62.
by JohnsUPS
Sun Apr 07, 2019 4:18 am
Forum: Off topic discussion
Topic: Learning Electronics
Replies: 56
Views: 2477

Re: Learning Electronics

Wow, this thread takes me back. I also built a crystal radio on a small board. Mom wasn't happy when I nailed it to the bedpost so I could listen to the radio at night. Stringing the long antenna wire from the upstairs window was met with a similar reaction. At some point had one of those project ki...
by JohnsUPS
Sun Apr 07, 2019 3:50 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: DS18B20 Max Distance
Replies: 41
Views: 42310

Re: DS18B20 Max Distance

Hi all, I have been following this thread for quite some time. I have been working on building a solar hot water heater controller. I thought I found a solution until this evening. I ended up buying a 1-wire Add On board for a PiZero to use for the Solar Hot Water Controller. I had it all up and ru...
by JohnsUPS
Sun Apr 07, 2019 2:28 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Soldering the USB port - does not work
Replies: 16
Views: 625

Re: Soldering the USB port - does not work

Should I try to solder them directly to the pin for the port and not to the PPs? Could that make it better? Yes - I second that. If soldered directly to where the pins from the USB connector protrude through the board, there is no reason why that shouldn't work. Prior to soldering to the PP's (or d...

Go to advanced search