Here’s my recent presentation about GradeCam at Launch EDU. I was nervous as hell.
Process
Hoop Diagrams and other process related posts.
Palmer – new motor
Palmer Trike rebuild and Maker’s Faire
Visiting the Maker’s Faire and chatting with electric vehicle builders taught me a quite a bit about my Palmer build and confirmed some of what I have been reading.
First, the transmission on the trike should go. The maximum torque of an electric motor is reached instantly and stays at that level for the majority of its operating speed range. A transmission is needed for gas motors since the torque varies at different RPM. In order to run an engine efficiently, you need to keep it running in certain RPM range. So when your starting movement, it needs to be geared down so that the engine can rev more for the low speed. Most electric vehicles don’t have a transmission because you get just as much power at a low speed as you do at top speed. With the old drive train on the palmer, I was always a bit surprised that when I tried to downshift going up a hill, it didn’t seem to change our speed at all. That makes sense given this information. So the transmission is getting dropped. That leaves more room for batteries.
Palmer Twosome powertrain considerations
So this Palmer Twosome is a bit of a conundrum for me now. It’s built like a beast. It’s 27 years old! It wouldn’t have made it this long had it not been built rock solid.
The problem I’m encountering now is that this rock solid 27 yr. old electric technology is a bit hard to come by today. I can find an electrical controllers from China for $79 that seem to do the same job as 50 pieces in this trike. Since the Palmer is a 12v system, it’s largely incompatible with parts from golf carts or scooters, which all seem to run on 24v, 26v, 48v, or 60v.
While disassembling, the motor busted a plate on the inside and I had to pull it open. the brushings are nearly gone and I need to find a replacement piece that I broke. So far I can’t find any info on this motor online. It seems that it’s no longer on the market.
Why are modern electric vehicle systems running on higher voltage? Time for me to investigate.
The first and most comprehensible info I’ve found is at Pedego Electric bikes.
What is VOLTAGE and which Voltage is best?
Voltage can be thought of as the pressure or strength of electric power. All things being equal (see AMPS below), the higher the voltage the better, because high voltages pass more efficiently through wires and motors. Very high voltages (100+ volts) can give you a nasty shock because they also travel through people rather well, but the sort of voltages found on electric bicycles (12 – 36 volts) are quite safe. As a rule, a 12 volt system is fine for low-powered motors, but more powerful machines work better with 36 volts.
The article goes on to discuss AMPS and Watts in a very comprehensible way. All of the info is useful for me.
With our existing 12V system, the Palmer Twosome is slow. On a slight incline with 2 people on board, it moves at a walking pace. On flat ground it might hit running speed, maybe. It’s sounding like the 12v motor is potentially part of the speed constraint. I’d think that with it’s beefy transmission and huge battery bank, it would still be able to hustle but that just doesn’t seem to be the case. This might encourage me to switch.
Batteries
The same Pedego article also talked about battery capacity. Battery capacity is rated in Amp/hours. There’s some weird factor about a 20h piece of that equation that I’m not bothering to understand right now. The important thing for me to note is that I should double the capacity theoretically needed due to system inefficiency. Once I get down to the nuts and bolts, I’ll revisit this part of the equation and really determine what I need.
The batteries that came with the Palmer are two Sea Volt Deep Cycle 215s. They’re 6 volts and have a capacity of 215 Amp/hours. To compare apples to apples, I’m gonna look at Watt/hours on all batteries and figure out how many watt/hours my system needs. After a quick refresher on my math skills,
Watt = Volts X Amps
Amps = Watts/Volts
215 X (Watts/Volts) / Hours X 6V
215 X (Watts/Volts) ÷ (Hours/1) X 6V
1290 W/hr in each battery
These batteries are over $240 a piece and after testing them at O’Reilly Autoparts, they seem to be in good condition. I’m not anxious to drop a $480 component of the system. Two 6V batteries only gives me a 12v system and I’m fairly confident these batteries aren’t gonna play well in series with any other type of battery to up my voltage.
Rebuilding our Palmer Twosome
Beth and I have taken on rebuilding a Palmer Twosome scooter. We found it on craigslist accidentally while searching for a tricycle for Burning Man.
I’m just gonna launch right into parts, pieces and what we’re doing.
We disassembled everything, sandblasted every part, and have been powder coating everything, piece-by-piece. I just tried pulling the power cables off the motor and the rusted nut broke something on the inside. Now I’ve pulled the motor apart and discovered a broken piece on the inside. There is a small square washer that snapped into pieces. It ripped the wires loose too.
The big question now is whether I try and fix this motor or replace it. Our Palmer scooter is 27 years old. Part of me would like to restore it to original, just fixed up, like an old car. Unfortunately the electronics are antiquated now. I would have a much easier time replacing the electronics with a modern controller, batteries, and throttle. That’s a heavy investment though. The batteries are the most expensive part of the puzzle. This is getting expensive. The old motor and electronics are much more complicated than a modern controller system. The pieces are expensive and the result is a slow scooter. For a $500 upgrade, our scooter could probably double in speed.
the Official Dudes of Hooping Calendar
Help build the SpinCycle by purchasing The Official Dudes of Hooping Calendar.
Two ways to contribute:
Presale has now started! Calendars will be shipping in early June.
Thank you to all the contributors helping make the first DOH calendar happen! All procedes go to funding the SpinCycle.
Resellers
We would love for you to resell the calendar. Purchase a dozen or more and get a $10/calendar discount. For resale purchases go here.
About the fundraiser
Every year Spin Cycle builds the one of the largest shaded spaces on the playa and dedicates that space to hooping and music. It’s a massive undertaking for the hooping community and we spend about $10,000 to make it happen. That’s been funded primarily through camp dues and by camp organizers. In addition to the expenses we incur each year, we bring nearly $30,000 of equipment to the playa, most is volunteered personal property of our team. For the first time we’re asking the community for support in order to provide a more sustainable energy supply for the music that fuels this hooping space.
Our greatest need is power; we’ve exceded our generator capacity. Sound systems draw a lot of energy and the amount or power used fluctuates quickly, presenting a unique challenge for a generator. Large sound camps run multi kilowatt diesel trailers to power them. Day and night we play music for the hoopers and running a generator is loud, expensive, and creates pollution. Rather than increase our investment in gasoline powered electricity, we’re shifting to a solar power system.
Solar systems are expensive. We’re currently working with a solar expert to design a mobile solar system that is modular. Our hope is to purchase part of the system this year to supplement our existing generator, and complete the system next year. The total system cost is looking to run somewhere between $8000 & $10,0000 and about $6000 of that needs purchased this year. (We’ll have detailed specifications being completed right now and will have that info soon.)
We’re planning on raising this in two ways: soliciting donations and “The Official Dudes of Hooping Calendar.”
More Info on the Calendar coming Soon!
We’ve already signed up an amazing line up of male hoopers to get this thing rolling! More info coming soon!
When not on the playa, we’re expecting this solar system to be powering other festivals throughout California. Any procedes generated will be reinvested in the Spin Cycle and our events for hoopers at Burning Man.
results so far..
Burning Man Ticket Survey
This is a quick independent survey about tickets for Burning Man in 2012. There are only four multiple choice questions in the survey total.
After years of organizing The Spin Cycle Camp, I did not receive a ticket in the 2012 lottery system. Grant and the others who build our camp didn’t receive one of the first 40,000 tickets either. In fact, so far I’ve only heard of a handful of people who received tickets out of the 100 people who camped with us last year. This survey is really just for my own curiosity. I’ll post results here and on Facebook.
Detailed Real-Time Survey Results
(Go to Form>Show Summary of Responses for graphs)
Here is a formatted PDF of results, as of 1:00 on Tuesday February 2nd, 2012.
I’ll be updating the PDF in the next day.
HOOP HIGH – Choreography Demo SET 1 AND 2 – Basement Jaxx Music Video
My story with GradeCam
Many know I’ve left architecture for the time being and work full time at a education start-up. My role ranges from strategic partnerships to marketing material to user interface design. I just finished this animation about out new free product for teachers. With a bit of sweat, I think we’ll replace Scantron forever.
I’m proud to be working on a product that can actually improve the quality of education. When teachers get instant feedback in the classroom, they can adjust teaching based on what the students do and do not know. This makes a huge difference.
The two main types of tests are “formative assessment” and “summative assessment”. A summative assessment (assessment = test in this context ) is a test you receive at the end of a learning period. This is the tests we’re all familiar with. You get a grade and your grade in the class reflects the score.
There’s a big push in education now for formative assessment, although the term is often misused. Formative assessments are given on a regular basis and are used so that the teacher knows what the students know. The point of a formative assessment is not to give the student a grade, it’s for the teacher to keep their finger on the pulse of the learning process. If everyone already knows ‘x’ but doesn’t know ‘y’, then the teacher should focus on teaching ‘y’. Without formative assessments, a teacher has a hard time keeping track of where students are at.
But here’s the tricky part.. testing means taking the time to grade and means data entry into gradebooks. If a middle school teacher has 6 classes with 30 students each, grading one assignment per day would mean 900 pieces of paper to grade in a week. And to make that worse, if you want to add that info to a gradebook, that’s 900 pieces of data entry to put in a spreadsheet. This creates an untenable situation for the teacher.
That’s why my mom came up with the idea for GradeCam. She was teaching 7th grade at the time and overwhelmed with data entry. She went back to college as a non traditional student to leave secretarial work and become a teacher… only to spend her weekends doing tedious data entry. Luckily my brother is a programming genius and wrote the software.
Now I’m working on making GradeCam available to all teachers everywhere.
We’re releasing a free teacher edition next week and a new website will be launching in just a few days.