I first had a interview with the hiring manager. After that the second round was a test where in you'll be given problems and you have to submit them in 3 days.
I applied online. The process took 7 weeks. I interviewed at Mainspring Energy (Menlo Park, CA) in May 2024
Interview
The interview process consisted of four stages, starting with an informational interview with HR to assess role fit and discuss key skills like Python and C++. The second stage involved behavioral and technical questions with the hiring manager, focusing on past projects and interpersonal challenges. The third stage was a take-home assessment requiring analysis of PID controllers, programming optimization, and test plan creation. The final stage included an in-depth technical discussion and a programming assessment in C++, covering topics like state variables, state machines, and PID controllers, along with behavioral questions about project challenges and team dynamics.
Interview questions [1]
Question 1
Interview 1: Informational interview
Talking with HR
Fit for the role they are looking for
The job description was important (Python and C++) were the main talking points.
Interview 2: Behavioral Questions + Small technical
Talking with hiring manager
Behavioral questions
Past projects I worked on
Tell me about a time you did not align well with your manager?
Interview 3: Take home assessment
PID controller and how it worked
PID Vs. Bang Bang controller
Pros and Cons
Which will you choose for an autonomous system
Programming
Update the code and make it more optimizable
Create a test plan
Intro, objectives, test scenarios and test cases
Interview 4: In-depth technical + programming **
30 mins (Behavioral)
Explanation of my past controller projects
PD Exoskeleton
Challenges
LQR Min Seg project
Sensors (gyroscope and accelerometer) why do they work well with each other?
Behavioral questions
Tell me about a time you did not align well with your manager?
PID controllers
Testing my knowledge on their function
Which will lead the state error to be 0
30 mins (Programming Q’s)
C++
State variables and state references *
What are they and how could you change them?
How do you edit a variable across the code?
Public, etc.
State machines and optimization using X ***
Controls Engineer applicants have rated the interview process at Mainspring Energy with 4.5 out of 5 (where 5 is the highest level of difficulty) and assessed their interview experience as 100% positive. To compare, the company-average is 38.3% positive. This is according to Glassdoor user ratings.
Candidates applying for Controls Engineer roles take an average of 49 days to get hired, when considering 2 user submitted interviews for this role. To compare, the hiring process at Mainspring Energy overall takes an average of 31 days.
Common stages of the interview process at Mainspring Energy as a Controls Engineer according to 2 Glassdoor interviews include:
Skills test: 33%
Personality test: 17%
One on one interview: 17%
Group panel interview: 17%
Phone interview: 17%
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