Charli Wilson

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since Apr 07, 2013
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cat urban chicken
Derbyshire, UK
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Recent posts by Charli Wilson

I would really like a bike trailer- reckon I could just about get my 10kg mower to the allotment up the big hill! But the crazy big and heavy things you guys are hauling, wow! I could never manage that!

The area I live in is not called the 'peak district' for nothing!
5 months ago
Pi zero W- £10
Sd card - £10 (32GB)
interface- £14 for two buses (if your sensors are all in totally different directions or you want  more than 20 of them, upgrade to a pi3 for £32 for and a 6 bus interface for £33)
Temp sensors- about £2 each for waterproof ones (dependant a bit on lead length, but nothing huge)
Cable- 20m is £12 for outdoor UV protected cable, £5 for a load of rj45 plugs
Connectors- £3 each

Humidity sensors- £30 each
Light sensors- I've never found a 1wire light sensor I'm afraid, so you can have one on the pi itself for £3, but not lots scattered around.

Cameras- you can only have one camera per pi, if you wanted 3 I would recommend a pi zero and camera for each camera setup (which adds to your power load a bit)- then you're looking at £10 for each pi, and £25 per camera.

Total (assuming 20 temp sensors, 6 humidity)
sensor setup: ~£360
cameras: £150

These are all wireless-enabled, but for ease of setup you might want a seperate router. Any old ADSL router will do- we get a new one every year when we switch ISP- so I'd have thought you could get one for free.

You would want to throw in £20 for shipping everything as well perhaps
5 months ago
Software- lets set up a pi. This is largely a list of links to official sources- as any instructions I write will go out of date with the next software release!

You want your pi, a power supply and an SD card. As well as a way of getting the software to the SD card, if you haven't purchased a pre-installed one- soa PC/laptop with an sd card reader.

We're looking at installing raspbian lite- this is command line only, and the display will be via a webpage that you can view on your computer/smartphone. If you want a display directly from the pi- hung on your wall or something, you'll probably want Raspbian Full as this has a GUI.

5 months ago
Hardware-lets wire up a sensor (a DS18B20)

You need to wire these up (3 wires) using this wiring diagram:

You want the V+ pin of your sensor to go to the cat5 orange cable, the data pin to blue, and the ground pin to blue white.

Here are some ideas on how to do this:

A TO92 sensor in an rj45 fitting- just get the pins into the right pins on the socket, and use your crimping tool to fit

A TO92 sensor soldered to cat5 cable, and covered in heat sink

A waterproof cylindrical sensor, soldered to cat5 cable and covered in heat shrink

And the one I'd recommend you use, though I can't find an example photo right now.. is to get pass-through rj45 fittings, or those with a loading bar (like these:, this makes it easy to get the 3 wires of the waterproof sensor in the right place- and them crimp the socket on.
5 months ago
So I can more easily keep track of what will be a fair few posts, I've started a new thread to document me making a raspberry pi temperature data collector, and it is here:
5 months ago
I am in the UK, so any links to products will be ones I can get hold of. I've tried to not be too specific- everything will also be available elsewhere in the EU/US. A lot of parts can be ordered most cheaply from China if you can wait for the shipping.

You will need:
A pi, I used a pi zero W but any pi will do, old pi a/B and pi zeroes use the least energy- if you're thinking of taking this project off grid.
A micro sd card to fit in said pi, I recommended 16GB or more. No need for anything massive though.
A one wire interface of some kind, I use the sheepwalk electronics ones:
The RPI2 v2 for the pi zero, or the RPI3 v2 for larger pi- this provides more transport buses and is suitable for more sensors, or sensors going off in vastly different directions.
DS18B20 temp sensors- either the TO92 ones, or the waterproof version if you need them to be waterproof, some ebay links as examples: or
Cat 5 or cat 6 cable, and a kit to fit your own rj45 ends to these is handy as well- you’ll need the rj45s themselves, i recommend the ones with a loading bar, or pass-through connectors- for ease of getting the wires fitted, like these: You’ll also want an rj45 crimping tool.
RJ45 3 way connectors- buy more than you need as they’re all really jippy. The black plastic moulded ones are better than the cream plastic ones, like these: . Or you could go for the sheepwalk electronics 4 way connectors, these are ace- RPI3a port splitter,

You will need a few things to develop on the pi. If you have a separate PC/laptop and wifi then all you’ll need is a microsd card reader. You will also need a monitor and keyboard with the relevant adapters to connect to the pi.
5 months ago

Jesse Glessner wrote:
HI CHARLI:   It sounds like you have an ideal setup. I'll keep an eye out for your forthcoming information on the system.
I have a RPi3 with a camera module but haven't used it for some time now. For a "monitor" I couldn't find anything small when I went shopping for one in BestBuy, but, they did have a small CHEAP television, very lightweight that I use for a monitor. It works great.

I haven't tried to download data into a spreadsheet, but I do want to use the camera module and download pics into my computer, or maybe another RPi with a huge amount of storage - as I want more of the camera modules around running on the RPi Zero WiFi units for data collection. In essence, a security system.

Check out motioneyeos- an easy to set up pi-based CCTV system. You can use the onboard pi camera, ip cameras or seperate smaller-pi based cameras. We use this setup at the allotment as well!
6 months ago
Currently my house pi has 34 sensors, and my greenhouse 29! Some up to 70m from the pi. They're mostly DS19B20 temperature sensors in a 'one wire' configuration (actually uses 3 wires), using easily available cat5 (computer networking) cable. You can either put all the sensors on one wire and circle it around- or with a bit more kit (which isn't expensive) have several wires going in separate directions.

I don't have a display, as in a screen on any of my pi. However the pi itself has a web server installed on it, and provides its own wifi. So you can wander up with a laptop/smart phone, connect to the pi and see the data displayed in a nice table- I tend to show current temp and min/max in the last 24 hours. I also have graphs of various things- there's some examples on this thread here:
It would be possible to have a screen plugged into the pi to display the same thing- either an old computer monitor or a specialist little pi-screen.

The downloaded data you can have in any format you wish! I store everything in a database and tend to generate the graphs straight from it, but no reason you can't download it to a csv or an Excel file to play with later. I've got 6 years of sensor readings stored on less than 1GB of space in a MySQL database, but other flavours are available.

Leave it with me a day or two and I'll find the instructions I wrote when I made everything, and include/link to them!

6 months ago
A BH1750 will give you lux readings, its a cheap i2c sensor and easy enough to read from.
6 months ago
I don't know where the leak is- I assume 'the tap' which is at the bottom, even though it was closed AND had a threaded fitting on the outside in an effort to prevent leaks! Al of the water leaks out, so the tap seems to most likely culprit.
6 months ago