MyRegister

MyRegister began as a simple Internet of Things (IoT) demo for students. I've developed it into what I hope might be a genuinely useful piece of kit.

MyRegister is a small, hand held device which uses RFID to capture (eg) attendance data. It stores data internally & uses WiFi to facilitate access to the stored data.
Physically, MyRegister is around 100x70x20 mm and weighs around 70g.

On the outside it's a small white box with a single button:




On the inside:

• WiFi enabled microcontroller
• RFID reader
• LiPo & charger

Mischief Avoidance

Operation

At power up, MyRegister searches for known WiFi networks & connects automatically to the last used network if it’s available, much like a laptop or mobile phone might.
If it fails, it starts its own network & becomes an access point (AP). It broadcasts its presence & unique identity (no two devices are the same). Users can connect to this network & then access the device via a web browser. A QR code on the reverse of the case can be used to ‘enter’ the URL.

At this point, MyRegister is fully functional but insecure as the AP is open & anyone in range can access it. This might be acceptable in some cases but it’s likely that users need to connect to a ‘private’ network.

On connection the home page is displayed:




On first use we would probably go to the network page by clicking on the NETWORK link at the top of the page.





This page displays the WiFi networks within earshot – hopefully the one we want is listed!

Entering appropriate network parameters in the boxes should connect the device to the network & close the access point.

It will acquire an IP address through DHCP & we need to know this to gain access, or we can use mDNS (aka Bonjour).

A QR code on the reverse of the case indicates the mDNS address(es).

A nice feature of mDNS is that if we have an AirPrint device locally we can capture & print a register with only a few taps on an iPhone or iPad.



Once a network connection is established it will be remembered. The access point won’t start again if it can connect as a client to a familiar network.

Home again

On the home page we’re invited to set the time. The device doesn’t have a Real Time Clock (RTC) & doesn’t remember the time. The time can be synchronised with a laptop/phone/whatever from a browser using JavaScript. This is quite useful as it means that we can’t be out of sync. I'll probably add a RTC, the jury is out on this. I've tried using NTP servers for setting the time but found this to be a little hit & miss.

When the time has been set it's indicated on the home page. There's other stuff here too, primarily for my debugging:



By default, the register closes automatically after 15 minutes but the time out is programmable from the TIMER page:



The home page is where the current register ‘exists’. As cards are presented a table grows on this page, this is more for reassurance (& debugging) than anything else. This is what it looks like:

Names & Numbers

1542003658,Purple Peter

186850250,Green Sarah

2581507054,Ehuoyan Ed

709254167,Stronglink Sam

2075269578,Jones Janet

2078743498,Smith Jimmy

1078358149,Bloggs Fred

1522158517,Smith Joe

2521235173,Brown Billy

320094120,White Jack

3943439050,Bluehat Billy

This file must be created/provided by the user and uploaded to the device from the UPLOAD page:




MyRegister detects the existence of the file & if it's found, offers us the opportunity to replace numbers with names. If the file isn't found the option isn't offered.

The sorting & filtering is actually achieved using JavaScript in the user’s browser rather than on the MyRegister device. This is of no particular significance but it obviously requires the browser to have JavaScript enabled.

The names.csv file is converted to a JavaScript ‘table’ by MyRegister and embedded in the register web page, as a consequence the page loads more slowly if the file is very large. The same list of names is used for every register, in other words it contains the names of every student we might encounter across all classes.

Clicking the 'Look up Names' button reveals:

Excel

Any serious 'local' use of the data collected by MyRegister is best off loaded to something like Excel. We can import data from 'the web' directly into an Excel spreadsheet:



Clicking the 'From Web' button opens a browser window in Excel which highlights those parts of the page which can be imported. Here I've selected (the green tick) the table showing RFIDs and times:



Excel asks where we'd like to put the data:



And Bob's yer uncle:



From here it's fairly simple to convert the numbers to names using a lookup table in the spreadsheet.

There are several advantages in using Excel:

• The spreadsheet can be formatted exactly how the user wants
• Data is easily collated & analysed
• Filesize on the device is reduced
• Provides an archive
• etc.

Storage

Whether or not we use Excel, registers are stored on the device using its file system:



There are a few 'helper' files here too, the actual registers are tagged with their creation date which makes them easier to find.
The strange numerical filenames are unix timestamps denoting the creation date/time of the register. This is to help with remote/automated collection of data.

All of the files on this page are 'clickable'. Clicking a register page opens the register which looks exactly like an open register on the home page.

A facility is provided for deleting single files here and it's possible to delete ALL registers (perhaps at the end of term?) from a URL.
Deleting ALL registers is quite drastic so I've deliberately avoided a 'single click'

It's possible for the user to upload their own 'helper' files too - note in the picture above there is an example Excel spreadsheet.

Despite the limited storage capacity there is scope for retaining several hundred registers. The html files are terse and correspondingly small.

Conclusion

/etc