Self-Scanning Units

3D Printed scanning units for delegate session tracking

For the second year running, we were tasked with tracking session attendance at Cisco UK & Ireland’s Mid-Year Event.

At the event the previous year, we used iPads to scan delegates into the sessions. However, for this year’s event, we were asked to deliver a quicker and less staff intensive method of recording delegate’s attendance at individual sessions. The reason for this was because the 2019 event was going to have a higher number of delegate’s in attendance, there would be fewer staff on hand to scan at session entrances and it all taking place in a much more demanding and complex venue.

The event was for 700+ attendees in an old warehouse with a very tight timetable for the day. So, it was imperative that there weren’t any bottlenecks getting the delegates into sessions.

We decided that building small scanning units that delegates could use to scan themselves into each session would be the best solution for this problem.

This project was a first for Purple Realtime, which would see us designing and building our own physical devices. Previously we developed software that could be used on ready-made products, so this presented an exciting challenge. Alex on the team had experience of 3D printing as a hobby and we all agreed that to create the volume of units we would need and to the standard that we wanted that 3D printing was the way to go.

We built a quick prototype for a proof of concept, using a Raspberry Pi with a camera attachment and good old cardboard and Sellotape.

Once we were 100% certain that the technology could do what we wanted it to do, we set about defining all the requirements of the units and any problems we could encounter in the venue.

We identified 3 main requirements for the self-scanning units;

  • Units need to be simple enough for attendees to use with almost no instruction.
  • Be able to connect to our serversto check attendees as they scan in real-time.
  • Require its own power supply.

We opted to use a Raspberry Pi Zero W as the basis for the scanning units for its small size, built-in wi-fi, and its flexibility. After refining the original cardboard model, we began to test 3D printed versions of the units giving ourselves a crash course in 3D modelling at the same time.

We added LEDs to give users feedback when they scanned their badges and put a bold “SCAN HERE” on the top of the units to make it clear what people needed to do.

Once happy with the designs we began production of the units. For this event, we determined that a total of 15 units would be needed to cover all of the session spaces, however, we chose to build 17 units to give ourselves some spares. To make the 3D printing easier, each unit was designed to be constructed out of four separate pieces. The 3D printer took about 20 hours to produce all four components for one just unit, and with the event date fast approaching we were printing pieces round the clock to get them all done in time.

A Python script running on the Raspberry Pi and some modifications to our cloud-based delegate tracking software meant that the units could then communicate with our servers. We even controlled which session each scanning unit was recording from the cloud.

Using the Raspberry Pi Zero meant the scanning units had a low power requirement. After some testing, we discovered we could power a unit for 12+ hours on a single small battery pack, even with continuous use. More than enough time to last through the whole day of the event.

Setting up all the completed units in our conference room for testing was very rewarding.

On the day of the event, all the scanning units were positioned at the entrances to the session locations. When powered on every scanning unit automatically connected to the venue’s wi-fi and paired with our cloud management system.

Brief instructions were given to attendees during the morning welcome keynote and it was satisfying to see people entering the first sessions and scanning themselves in without an issue and without really slowing the procession of people down as they entered.

We kept a close eye on the scanning units during the day, we did have a couple of issues with the venue’s wi-fi as the network got crowded. Thankfully we installed warning LEDs on the units, this enabled us to quickly identify units with a problem and a simple ‘turn off and on again’ sorted the issues. Overall, we felt that the scanning units performed really well and coped with the large volume of users without any significant issues.

After the event, we were able to give the client all the data the scanning units collected about the attendance for each of the sessions during the day. The client was pleased with the data as they were able to perform analysis on which were the most popular sessions, discrepancies between the numbers booked and numbers in attendance, and the time people actually arrived at the sessions. With the scanning unit data, our client was also able to update training records for attendees as a few of the sessions counted as part of their internal training and development.

Designing and manufacturing the scanning units in the limited time we had was a big challenge for the team at Purple Realtime, but we couldn’t be happier with how they performed in the end.

We are always excited to take on projects that push us and we always strive to provide the best solution to a problem, even if that solution takes us out of our comfort zone. 3D printing objects was relatively new to Purple Realtime when we started this project, but we now feel confident doing it and we look forward to finding a use for it in future projects.


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