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Hot water control using a Raspberry Pi Zero W

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Following on from the first blog about the hot water heating control here's what I put together for the mounting.
Whilst looking for a suitable enclosure I came across an surface mount electrical socket back-box and I got to thinking "how can I mount the RPi W and relay in this?" so after some head scratching I thought about 3D printing some carriers to go inside the back-box.
The picture above shows two carriers printed to support the RPi and the relay board.

Then I made the required entry holes in the back-box for the power cable (USB), the mains switching cable for the relay and the temperature sensor cable.

This contraption has been sitting on my desk for a few weeks running quite happily and I've been checking the event log to make sure it's been switching on and off when it should.

Next to interface it to the existing wiring.

Hot water Remote Control using a Wemos D1 .... then a Raspberry Pi Zero W

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For quite a while now I've been meaning to put together a project to control the Hot water heating remotely from my phone, I all ready have a 2nd generation Nest to control the heating but don't fancy spending the money for the 3rd generation just to add the water heating function.
I started with the plan to use a Wemos D1 Mini with a couple of the plug-in modules like a relay module, processor module and a button module all placed on the dual base PCB.





For those of you not familiar with the Wemos D1 you have to be aware of which pins the different modules use because the relay module uses D1 which also happens to be used for one the I2C pins so if you wanted to use the I2C OLED display module it would clash.  I decided to re-wire my relay pin to use D6 (GPIO12) as this is the default pin that the Sonoff / arendst software uses for the relay anyway.

Once the parts were assembled and the software flashed (the button module happens to be the flash button as well)

The idea was to…

DIY Chrono Mark II

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Well it's been a long time since I started off this project and I've made a few changes along the way and a few people have had a go at making their own Chronos based on the entries in this blog, some followed the design and some incorporated elements of their own into the design to improve it.
There were a couple of the things I wasn't keen on with my design: -
The fact that it was not a round tube but a teardrop and therefore may not always line up with the rifle and look a bit odd.An external charger circuit was required to charge the internal battery.The switch was mounted at the other end of the tube from the electronics and was a bit of a pain to wire up and assemble. So along came the Mark II with the intention of improving on those issues.

The main reason for the teardrop design was to fit in the electronic modules with the central tube so I needed to come up with a design where I could place the modules and battery around the perimeter of the tube whilst keeping th…

New Android app for the Chrony F1

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I recently bought a damaged Chrony F1 from a chap that had accidentally shot it, it never ceases to amaze me how companies can design and sell things that by design you shoot at and not put adequate protection in front of the delicate electronics.

The front casing had been hit and had a large dent in it that cracked the LCD and dented the crystal body, after a suggestion from John on the Facebook group "SHOOTING CHRONOGRAPHS U.K." I looked at Radio spares for a replacement and bought this screen 184-7715, it worked like a charm and after a bit of panel beating and a lick of Hammerite Dark Green paint it looked as good as new.
One other thing I did before shooting at it was to buy some 10mm Acrylic sheet from eBay to make some clear shields to protect the display and the rear sensor block.

So when I started to use it I realised that I'd have to write down the readings and calculate the power myself later ..... s*d that! surely there's an app for that, if not I'll …

DIY Chronograph Accuracy testing

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A few people have attempted the DIY chronograph build, at least one person improved the design and made an excellent version of his own.

I had a a question asked about the accuracy of the chronograph so I setup some testing over the weekend to try and determine if it was as accurate as others out there.

I don't have access to a calibrated air rifle or similar, if something like that even exists?? so I decided to use a good quality Oscilloscope (Picoscope automotive), which connected to my laptop via USB and do a comparison with the output from the Nano (in uSeconds).

For each measurement I took a screenshot of the waveform from the Oscilloscope and the serial data from the Nano, this shows the correlation between the actual time between the first beam being broken and the second.
There is also a google sheet showing the data that was recorded during the test here you can view the data and make your own decisions, for the last few shots I added a Chrony F1 about 3m away from the ri…

Updated PC software for the DIY Chrono (and Combro)

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Just a quick update for anyone that has tried the PC software application for my DIY Chrono before, I've re-worked it a bit and changed the layout and moved the settings to a separate screen.

Also now I've fixed the Combro option not working so it should now report the correct values, if not please let me know as I don't own a Combro ..... the whole point in making my own.

Some Screen shots ... The main screen shows all the shot details in FPS and M/S along with a min FPS, max FPS and a Delta FPS.
On the right there is a list that adds each shot's data to a row so you can see the history.
At the bottom is a chart section that, if the checkbox is checked, shows the data graphically, there is a tab for FPS and one for energy. You can also select the option to store the shot data to a file on the PC, the path is set automatically but you can type in your own.  The data is stored as a CSV file and can be opened by excel and used to create a graph.

The settings screen is se…

Chronograph - Another option

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After printing the last model I ran out of the white filament and decided to give the black filament a try and was surprised to get a print that looks and feels a better print, I think it's an optical illusion though, black just seems to look better.

Anyway I decided to do another design of the enclosure one without the battery for those that just want to connect to their laptop via the USB cable and us the PC software from elsewhere in my blog.

This design is a bit smaller that the first as there is no battery, switch or charging cable, I did leave in the holder for the Bluetooth module so it can be used with the smartphone app but you will need to power it from one of those portable emergency batteries via a USB cable.

You can get the STL files from Thingiverse


I've also been making some changes to the Arduino sketch to improve the functionality, I've implemented the use of interrupts to trigger the measurements so that some other things can be done via the main loop lik…