iSpindel 25° Calibration in Pure Water
Who says we need to do this?
I’m not exactly sure the exact inner workings of the iSpindel code that make this necessary, but universam1 who runs the iSpindel GitHub page says it’s not an option, it’s a requirement. I’ve included a few quotes from him below as well as an excerpt from the official iSpindel FAQ page.
Do I have to tare the iSpindle with weights?
It is indispensable to enable the iSpindle functionality! Add weights such as nuts, lead balls etc. to the bottom until the inclination is 25° from the vertical. See also example pictures in the documentation. Normally about 20g are sufficient. +/- 5° deviations are often still acceptable.iSpindel FAQ Page
Why do we need to do this in the first place? Can’t you just design the iSpindel to float correctly without adjustments?
I think the main reason is that this is needed is that everyone is buying individual components from different manufacturers around the world. As consumers, we don’t have the ability to check the exact weights of products before we buy them. For example, 18650 batteries vary in capacity and weight from manufacturer to manufacturer. Since the functionality of electric components isn’t dependent on their weight, we need some sort of mechanism for changing the angle after iSpindel assembly is completed to adjust for differences in the manufacturing process for the “same” components.
How the Jeffrey PCB handles angle adjustments in pure water.
The Jeffrey has two mechanisms for adjusting to 25° in pure water. By using one or both of these methods you will be able to get to 25° in pure water.
- The battery and battery holder are movable and can be installed in multiple positions due to the surface mounted battery holder and the over-sized solder pads on the PCB. I’ve included a ruler on the PCB to better quantify battery position. The battery is the heaviest part of the iSpindel and being able to move it has a drastic impact on how the iSpindel floats and allows for an increase adjustment of about 50° angle from the lowest battery position.
- A place to add weights. The Jeffrey has a perforated area to afix weights at the bottom of the PCB. Weights can be glued, sewn with needle and thread, double-sided taped, pull tied, the possibilities are as vast as your imagination. When I added about 2.9 grams of weight it decreased angle by about 14°.
Adjusting the angle.
I will be balancing two different styles of iSpindels. I have The Jeffrey which was designed by yours truly. I also have some of the first iSpindels I made from the very popular PCB 4.0 by CherryPhilip. The iSpindel FAQ states that getting within +/- 5° of 25° is often acceptable when in pure water (somewhere between 20° to 30°). I will consider +/- 2° the sweet spot (somewhere between 23° to 27°).
I do an offset calibration on a perfectly level surface then measure the angle in water. If I add weights or move the battery, I once again do an offset calibration then measure the angle in water. I’m currently getting the angle value directly from the iSpindel Info page that is accessible from the iSpindel when it is in configuration mode.
The Jeffrey – iSpindel #1
- 24.17° – No weight, battery at 10 mm position.
- 75.43° – No weight, battery at 0 mm position.
- 26.30° – Moved battery back to 10 mm position. Note: Not sure why the angle was different from the original angle but it is still within the +/- 2° so I will leave it. Maybe it is due to additional solder on the PCB.
The Jeffrey – iSpindel #2
- 23.73° – No weight, battery at 10 mm position.
The Jeffrey -iSpindel #3
- 28.63° – No weight, battery at 10 mm position.
- 14.85° – After adding two nuts (2.9 grams) as weights with double-sided Gorilla tape
- 42.22° – 2.9 grams of weight, battery at 0 mm position (testing highest possible battery position with weights).
- 19.93° – 2.9 grams of weight, battery at 7 mm position.
- 22.23° – 2.9 grams of weight, battery at 6 mm position.
- 23.95° – 2.9 grams of weight, battery at 5 mm position.
The Jeffrey – iSpindel #4
- 26.78° – No weight, battery at 10 mm position.
The Jeffrey – iSpindel #5
- 25.04° – No weight, battery at 10 mm position.
PCB 4.0 by CherryPhilip
Please note that my PCB 4.0 boards were installed with the wrong battery holder. I ordered surface mounted battery holders instead of the PCB mounted ones, so I bent the surface mounts to solder them into place. Possibly as a result, I also had to file the PCB down to get it to fit in the petling. This could have something to do with the angle being too low on my 4.0 PCB builds but I’m not sure. I did email back and forth with CherryPhilip but we were not able to figure out why the angle was too low. The battery I have is the correct weight. Others have reached out to me and I have seen other posts online who have the same issue as me. I have also messaged with people that don’t have this issue with the 4.0 PCB and their iSpindels float totally fine without any modifications. Why some people have this issue while others do not is still a mystery to me.
On the forum HomebrewTalk.com user Wild7s posted pictures of how he added lead weights in tape to the top of his PCB 4.0 to get his to balance. If you are aware of other methods please ensure you let me know about them so they can be shared here with others.
PCB 4.0 – iSpindel #2
- 16.42°- Baseline with no changes.
- 17.45°- After putting foam in the bottom of the petling and filing the top of the PCB down.
- 20.43°- After putting foam in the bottom of the petling and filing the top of the PCB down as far as I could without damaging the USB port. Had to melt plastic switch with soldering iron to shorten it.
PCB 4.0 – iSpindel #4
- 15.85° – Baseline with no changes.
- 18.50°- After putting foam in the bottom of the petling and filing the top of the PCB down.
- 20.48°- After putting foam in the bottom of the petling and filing the top of the PCB down as far as I could without damaging the USB port. Had to melt plastic switch with soldering iron to shorten it.
Were we able to get all seven iSpindels to within +/- 5 degrees. We were able to get all of The Jeffreys to +/- 2 degrees which is fantastic! We saw how adding weights to The Jeffrey can decrease the angle in pure water and how moving the battery up can increase the angle in pure water. Once balanced to 25 degrees in pure water we can move onto fermentation or sugar water calibration that ties in the readings from the iSpindel to a classic hydrometer, once this is complete the iSpindel is ready for service.
Joey Joe Joe Jr.