3D Printed Motorized OAG Focuser - Part II - Project Updates & Calibration 

Glad you found the project helpful! If you use a LiPo, you absolutely have to use a charge controller, or you risk catching it on fire (no joke!) I toyed with that idea, but eventually rejected it as it did not provide that much value. That being said, you may be able to source as much as 500mA from the Arduino 5V pin, and with that, you only have 1 cable to deal with. You have to use a 5V stepper for that to work. I will update the project accordingly. Clear skies!

​ @Dark Sky Geek - Astrophotography (sorry in advance, this response got a bit long by the time I finished it 😂) I've had lots of previous experience working with lithium cells and building custom packs - I run my telescope setup from a 400Wh LiFePO4 4s4p set of 38120 cells in an ammo box, with a power meter display in the lid, 3x xt90 panel mount sockets for my main power devices, 3x 5.5mm barrel jacks with individual PWM control to adjust the power going to each dew heater, it's insulated/internally heated with a temp controller to keep the cells warm during the winter, and it'll even jumpstart my car lol The idea of getting rid of one more 12v cable sounded too good, so I ended up throwing the circuit together with parts I had to see how it'd do. I used a 12ohm 2 watt resistor between the boost reg's 12v output and the battery to limit the charge current at the USB port to ~270mA. I'm also testing a 100mA bleed-resistor balancer to pull down any cell >4.15v. It won't have min/max protection, but it shouldn't be able to exceed 12v or fully drain the battery, but I'll have to bench test and see if this config holds up. lol this idea is very quickly becoming less-simple than originally intended, but I could also add a mosfet to switch the 12v power on only while USB 5v is connected so it doesn't self-discharge when it's not being used. 12v is probably not as useful for OAG purposes, but I think it would still be advantageous if you wanted to build a setup capable of really snappy-quick focusing. I'm running the direct drive SCT focuser at a speed of "16" in the arduino variables which gives me a full motor rotation in about 4 seconds - I'd be surprised if the 5v version could match that. I don't have a 5v one to test and compare or I'd throw it on and see, so this is mostly guessing how it should perform, but steppers produce torque as a function of current, usually limited by the motor driver(or possibly the coil winding resistance with these small steppers/drivers), so for an identical motor and current at either 5v or 12v, you should get the same low speed torque, but higher peak rpm on 12v before losing torque/skipping steps. I'd also guess the 5v motors are wound differently to get more usable torque with an appropriate current draw for typical 5v sources as well, so they could be even slower than just the difference in voltage would be responsible for. I ran into this situation while building my CNC - Switching from 24v to 48v resulted in a huge boost in rapid speeds without skipping steps(but those drivers are also pretty advanced). If these tiny drivers aren't that fancy and are just using the coil resistance to limit current, then it'd likely just cook a 5v motor with a 12v input/driver, but it'd certainly be torquey and fast while it lasted lol Anyway, if I do install the 12v step-up circuit into my actual imaging setup, I'll let you know how it goes after a couple nights worth of focusing runs. Thanks again for making this so good for the DIY crowd 😄

It’s compatible as in you will need to swap the helical focuser.

Si vous utilisez seulement le système de mise au point, alors pas la peine de se soucier du filter wheel proxy car il n’est utile que pour un OAG.

@@darkskygeek ok, merci pour votre réponse et vos contributions...!

Hi! I have received several such requests, but unfortunately, the answer is no. I will, however, continue to support this open-source project and those who undertake to build it.