Monitoring Data with the Arduino and ThingSpeak

In conjunction with my last post I thought I would monitor my hot water tank to track the temperature variations throughout the day, mainly to use the temp change to identify when someone has taken a shower and judge the need to heat the water up so there is some left for bed time (this will be done automatically by the Arduino code).

First I searched around for a free cloud data storage solution, I'd used Pachube/COSM previously but COSM had changed hands again and I found it was always a bit unreliable for me anyway.

I tried Nimbits.com first of all but found it quite difficult to get the UNO working with the code on offer and the help information was a bit of a mismatch with sample code not being up-to date with the latest API, having said that the forum was well supported and I got quick answers to my questions.  The main problem is that when I got it working my data on the graph contained random values which made the chart useless, I thoroughly checked the values that I was posting and the spurious data was not coming from me.  One plus was that they had an Android app on the Appstore so viewing the data was easy.

I then tried ThingSpeak, getting the UNO/Ethernet shield up and running was a lot quicker and I was posting temperature values within minutes.  Another nice feature was the ability to clear the current data from the channel, ideal when logging data during development that's not relevant to you actual job.

The chart looks nice, updates continuously and if you hover over the points a nice panel pops up with the data point details.

I've only just scratched the surface of ThingSpeak so there's still loads of stuff I just don't know about but it definitely enabled me to get up and running very quickly.  One thing missing from ThingSpeak was a dedicated Android App but after a couple of hours with App inventor I was able to put together a usable App that lets me view the data whilst out and about (sad I know).
It is also possible to embed the charts into other web pages using an Iframe.
There are plugins that can be created, there is a sample of a Google gauge but I still can't get it to work.  The forum doesn't seem to be as well supported as the one on nimbits, maybe there are less users.

The App inventor source can be found here. (updated to appinventor 2, import the aia file to app inventor 2)
The APK file can be downloaded here.
After running just type in your channel number and read key and click "set" and then "update"

DIY Chrono Shopping list

Latest project update for 2026 here

A few people have expressed interest in making a DIY chronograph so I said I'd put together a shopping list.

There are quite a few options for the display type so I try to give the pros and cons at each step.

Firstly, the processing power.
All my projects are done using the Arduino family, including the many clones out there, I've used original Arduinos and Clones from China all without any problems. (A PIC Micro will do just as well with the same hardware)

Arduino Mini Pro	Arduino Nano
These are available in 5V 16MHz and 3.3V 8MHz versions, I used the 5V versions @ 16MHz to get the best uSecond resolution, I believe that the 5V versions can be run at 3.7V and still run at 16MHz. This device needs an external USB to serial adapter to allow programming but, once progr ammed, can be fed from a 7V source via the on-board regulator (RAW input) or a regulated 3.3 to 5V supply on the VCC pin. I bought mine on Ebay from here for less than £3 but it took 27 days to arrive. Others on Ebay search	These are the boards I've been using, mainly due to the USB connector for both programming and supplying 5V.  I use an Eveready unit that uses 2x AA batteries and steps up the voltage to 5V, I connect this with a standard micro USB lead. Apart from the on-board USB and the in-circuit programming connector (far right) the specs are the same as the Mini Pro. These can be bought on Ebay for around £4 from China and around £10 from the UK, they're a little more expensive due to the on-board USB. Ebay search.
Display Options
This is the top of the range display £7 from China but has the advantages of being colour and also touch screen. I didn't go very far with this display but I think it would be good in a larger Chronograph that has a large detection curtain.
	This is an I2C connected display and can come in yellow, blue, white and red. This is my choice for my portable sensor. It's very easy to program and is a similar size the the sensor tube so is a good fit, see this post. You can only really display one value, I chose FPS because that doesn't require you to input the pellet weight, you can generate a little look up chart for you pellets.
I dug out an old Nolia 5110 phone display that was set into an Arduino UNO shield and added it to the DIY Chronograph family, it works pretty well and has a very good contrast for outside readability and the 5 way switch at the bottom centre allows for a menu system to enter the pellet weight. I can't get the shields any more but the screen can be bought off Ebay for a couple of quid from China and around £7 from the UK, these displays not on the shield work on 3.3V only so require some level shifting when used with a 5V arduino.
	A cheap and cheerful display that can be bought in many webstores an Ebay, they're nearly all the same connection standards and have Arduino Libraries readily available and can come with or without backlighting.
Similar to the 2 line 16 character display just a bit smaller, easier to package and can come with and without backlight, the non backlight versions tend to use an LCD technology that means they're a good contrast  and can be good in sunlight.
	Fancy using your Android smartphone as the display then this is what you need, available from £5 in China to £15 in the UK. Be careful, this board comes with and without the back PCB, without it is a bit fiddly to use and works of 3.3V only. Ebay search
Other parts
	I chose Aluminium tube because I wanted to thread it to fit my 1/2" UNF silencer adapters on my rifle and pistol but you could use any tubing you liked, depending on how you want to fix it. I bought mine on Ebay from here. You will need to get it cut to length and threaded if you want to do as I did. Maybe you have an old silencer that you could modify.  See this post for assy. details
The sensor LEDs were bought from RS components, they are available on Ebay but at a huge markup Photo sensor - OPL-550a Ebay Farnell RS components IR Emitter LED OP240A Ebay Farnell RS Components
Software
Arduino	Android
I have quite a few version of the various sketches so if you would like a particular version just request it in the comments and I sort out a link. Nokia 5110 shield sketch Nano with 7 segment display Chrono with 8x2 LCD	Here Aptoide store download

Cheap Colour TFT with the Arduino

As long as I've been working with Arduinos I've always wanted to use a colour TFT to display stuff but they were always quite expensive, well now I've found a quite cheap one that's relatively easy to programme. Ebay link.

I read a blog article from http://tronixstuff.wordpress.com/2013/04/26/tutorial-arduino-and-ili9325-colour-tft-lcd-modules/ about using an inexpensive TFT from Ebay (China) it costs about £7 inc. delivery, worth a try.

www.tronixstuff.wordpress.com is definitely worth a visit as there are loads of Arduino tutorials to read.

There's already a library available from another site http://henningkarlsen.com/electronics/library.php?id=51 called UTFT.rar, download it and install to your library folder.

The library comes with three fonts, small, large and a seven segment calculator type font, unfortunately the seven segment font doesn't come with a decimal point so when you use it to display floating point numbers with the printNumF command it doesn't display a decimal point just some small random characters.

I contacted the Library author Henning Karlsen and he was very helpful in pointing out information for creating your own fonts and some already created extra fonts. http://henningkarlsen.com/electronics/r_fonts.php

A couple of things to be aware of though: -

• The fonts use up memory, quite a lot of memory for the full fonts so be aware.
• The code includes all the drivers for all the various chipsets, to reduce the memory edit the memorysaver.h file in the UTFT folder and remove the commenting from the lines for the chipset you don't need.  If you don't do this then some examples compile to more than 32K.
• On the screen I got, using the UTOUCH library from the same site as the screen library, the touch functionality wouldn't work.  I'm in contact with the supplier to try and understand if it's an issue with the screen or the library.
• There is also an SDcard socket on the back of the PCB but I've not yet tried it out.

The library includes the ability to draw recangles, circles etc and I noticed a new geometery library that will let you draw arcs, pie slices.

Overall I think it's well worth the £7 even if the touch doesn't work although it would be fantastic if it can be made to work.

The memory limitations are a pain when you want to use a large font size but if it's a must then you could look at using a Arduino Mega or the Chipkit Uno equivalents, I beleive they have more memory to play with.

Finally, some pictures for the TFT, I've modified my Chronograph code to run with the TFT screen, the only issue is the lack of a decimal point in the seven segment font but I should be able to modify the font source to add one.

 

 

I've also started work on a shield for the UNO so that it can be plugged directly on top and also included five switches along the bottom, using a resistor ladder network so they only use up one analogue input.

 

If anyone interested in a shield then just let me know in the comments.

 

New Arduino Leonardo

Another board from Arduino.cc

Arduino have announced another micro-controller board based on a new ATmega32u4, this processor also takes care of the serial communications with the host PC negating the need for a separate serial to USB chip.

There are a few other differences between this board and the trusty UNO: -

• A micro USB connector. At last!
• The SPI bus on the ISP connector no-longer uses any IO pins.
• The device will act as a USB keyboard or mouse to the host PC.
• The board is available with or without the headers, without being slightly cheaper.

I looked at some UK suppliers but they were not showing availability until the 11th of June so it might be worth getting your pre-orders in now.

Also there is an update to the Arduino IDE available, this adds support for the Leonardo as well as multiple language support as well as other changes.

Download link here

Release notes here