Hi ,

Here's some updates and news from FIRST^® Tech Challenge.

In this week's blast: 

💻 Tech Tip of the Week

🏆 Championship Corner

👏 Thank you, Volunteers!

❌ FIRST Tech Challenge Machine Learning Site Closure

💼 FIRST^® Certified Professional Development

Tech Tip of the Week  

This Tech Tip of the Week is Part 2 in a 3-part series surrounding a question that we are asked at events all the time - “What makes battery voltage sag?”. As a battery is heavily used, teams will notice that the voltage of the battery temporarily decreases from its starting voltage during periods of heavy use, and then generally raises back up once the heavy use has subsided. So, what causes this? 

There are LOTS of reasons why battery voltage will sag during use. In last week’s Tech Tip, we talked about battery chemistry to give an idea how a battery works, and we talked about how motor torque is inversely proportional to the power consumption (given a constant load). In this week’s Tech Tip, we will cover two more common reasons - cell health and battery temperature. In subsequent Tech Tips we will cover other reasons, such as the internal resistance of the battery. 

Battery cell health is an important factor in the overall health of a battery. A NiMH battery used in FIRST Tech Challenge is a multi-cell battery, meaning it is composed of individual smaller batteries connected together. Each cell contributes to the overall power output of the battery. As a battery ages, individual cells in the battery may age at different rates - this aging can lead to degradation of cell material, electrolyte breakdown, and creation of dendrites that can eventually puncture the cell wall from inside the cell, among others. Most often this cell breakdown is accelerated due to improper storage, overcharging, deep discharging, excessive temperatures, or physical damage (especially due to dropping). When a cell fails, it can lead to a reduced capacity of the battery pack, and the battery will not last as long on a single charge nor will it be able to provide the peak power output that it previously could. Failed cells can cause other cells to fail prematurely, primarily due to overcharging and imbalanced voltage because NiMH batteries and chargers for NiMH batteries do not contain a load-balancing management system for individual cells. In some cases, failed cells can cause short circuits, overheating, and increased risk of fire/explosion! If you are suspicious of a battery, get it tested before using it again.  

Battery temperature is also an important consideration. When a battery is being charged, it will likely become warm and even slightly hot to the touch - this is expected and natural due to the process of recharging a battery. NiMH batteries deliver their best performance at moderate temperatures. When a battery is hot from charging, its internal resistance increases (we will cover internal resistance in a future segment) which can lead to reduced power output. Allowing the battery to cool down before use helps to ensure optimal performance. This process of allowing the battery to cool down before use can also prolong the life of the battery. This advice should also be tempered with the knowledge that most modern NiMH batteries are generally designed to handle some degree of heat; if you need to use the battery immediately after charging, it’s usually safe to do so as long as the battery is not excessively hot to the touch. However, understand that it may not provide the maximum level of power output as it would have if it had cooled first. 

Championship Corner

Championship Conferences

Attending the 2024 FIRST Championship presented by BAE Systems? Join us for FREE conferences April 17-19 on a wide variety of topics such as program specific resources, workforce development, school, and education implementation, FIRST sponsor content and more! Download the 2024 FIRST Championship App to see the full conference schedule.  

FIRST Championship Information 

If your team is joining us at FIRST Championship make sure to check out the 2024 FIRST Championship website and download our 2024 FIRST Championship App to stay up to date on all the event  information.

You'll want to read through our FIRST Tech Challenge Event Guide Addendum for the latest and greatest information about FIRST Tech Challenge at FIRST Championship! 

Thank you, Volunteers! 

We want to give a BIG thank you to each volunteer who gives their time and energy to FIRST students as mentors, coaches, or event volunteers. In honor of Global Volunteer Month in April, we are celebrating all the important work our volunteers do within our communities, schools, and organizations. 

Enter our Volunteer Month Raffle: All volunteers are eligible to win free FIRST swag. One entry per person, raffle is open now until the end of April. Submit for your chance to win! 

Share why you volunteer: This month we will be sharing stories on our blog and social media about volunteers within the FIRST community. Share with us on your social platforms why you volunteer with FIRST and the impact you have seen on your students with #FIRSTvolunteers. Your post might just get boosted by FIRST! 

FIRST Tech Challenge Machine Learning Site Closure 

The FIRST Tech Challenge Machine Learning Toolchain, https://ftc-ml.firstinspires.org, will be shutting down for the season on Monday, May 6, 2024. Unfortunately, due to site maintenance costs we cannot keep the toolchain available during the off-season.

However, this summer the site will be undergoing necessary maintenance for next season, and once the maintenance is completed those watching the fmltc GitHub repository should be able to migrate their instances to the new infrastructure. As with all end-of-season closures, access to the site will be unavailable during the closure and all uploaded and generated data in team accounts will be deleted before reopening on kickoff next season.

FIRST Certified Professional Development 

FIRST Education is hosting both remote, and in-person regional and academy sessions for FIRST Tech Challenge. Sign up for one of our upcoming professional development sessions and grow your knowledge and skills by practicing student elements of the FIRST program! 

More information can be found on our professional development website and registration is through Eventbrite. If you have questions, email firsteducation@firstinspires.org.

Upcoming In-Person & Remote Sessions:

• April 15, 16 | George R Brown Convention Center | Houston, Texas
• June 10-14 | Forest Lake Academy | Orlando, Florida
• June 27 & 28 | Online
• July 29 - August 2 | Davis Middle School | Compton, California