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About jbrazio

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  1. And have less backlash.. that's why I used them in this project. But you're right the best possible solution would be to print hubs and use a belt avoiding printed gears altogether. BTW, in our plastic world.. they work nice even in PLA, here is a good channel about the topic:
  2. So here you have, the PCB and schematic files for Ardufocus ! Please note this revision is untested but it passes ERC and DRC. PCB size: 50x55mm
  3. So here you have, the PCB and schematic files for Arduheater !
  4. No worries, I tend sometimes to take a while to respond because I receive no notifications from this forum (?), I'm also available @jbrazio. I never really shown my custom take on dew strips.. so here it go, the BOM for it is: 3D printed template Kanthal Resistance Wire 24AWG Kapton tape GX12-4 male & female connectors Wire & heat shrink tubing
  5. You're right, I was not thinking about the specs of the sensor but rather some "calibration value".. which in fact are the same thing. The values I use by default are pretty generic ones for the 10k NTC. The NTC resistance (THERMISTOR_NOMINAL_VAL) is 10000 Ohms (10k) at 25.0 ºC ambient temperature (THERMISTOR_NOMINAL_TEMP). #define THERMISTOR_NOMINAL_TEMP 25.0F #define THERMISTOR_BCOEFFICIENT 3950.0F #define THERMISTOR_NOMINAL_VAL 10000.0F I'm not familiar with the BME but the DHT sensor sends out a 40 bits stream of data with encodes directly the temperature and humidity values [plus a checksum], you just have to convert them into floats, there is no "tuning parameter(s)". But usually the error on these sensors are rather linear for a deterministic temperature range, if you need increased accuracy you may build a lookup table of offsets vs temp range. I believe for the application we are using it here one overall offset is more than sufficient. @adyj1 The NTC you provided is more than suitable. If you have a look at the datasheet you'll find the B coefficient value of 3470 or 3380 depending on the part number. http://www.eaa.net.au/PDF/Hitech/MF52type.pdf
  6. There is no "factory" tune for the temp probes (either the DHT or the NTC) instead I allow the user on the GUI to define offsets for them, so if you find that a particular sensor is out by 1ºC you just set it's offset and you're good to go. What is currently missing on the system is EEPROM support so all the parameters are kept.
  7. Not a silly question. The Moonline protocol allows the activation of a temperature compensation feature but this is not implemented on Ardufocus, the reason why ? I find it useless.. the auto focus program should be the one handling the temperature compensation, just like SGP does. The thermistor still has an important role because you need to provide to the AF program the environmental temperature so it can temperature compensate (not that useful IMO) or automatically run the AF routine on each degree change.
  8. Arduheater 0.3e released. See changelog since last release. Please report back any issues you may have found.
  9. Sorry for the late reply but for some reason I'm not getting e-mail notification of the subscribed topics. @NickK In one hand powering down a stepper driver will make you lose accuracy exactly has you described, on the other hand leaving the driver in holding torque will make the motor heat. My main concern is not the driver itself but the motor, the 28BYJ-48 running at 12V gets pretty toasty. Has this is not a one size fits all situation I leave up to the user to choose by toggling MOTOR1_SLEEP_WHEN_IDLE. However there is a catch, you need to have full accuracy during an auto focus run, i.e. when you're moving on the focal axis and taking measurements and then moving back to the best position; you don't really need that much accuracy between runs, i.e. you auto focus now and then auto focus in one hour. For this reason even if you have MOTOR1_SLEEP_WHEN_IDLE enabled there is an undocumented flag that defines a timeout after the last move before the motor's power is cut, by default this is set to 5 seconds. This should be set to accommodate the time it takes for your setup to take a frame and analyse it before moving into the next position, this way your motor will be powered off during most of the session but still keep accuracy when it is really required to. If the changes required to make the DRV8825 work are as trivial as increasing the delay after a sleep instruction then I suggest the following: https://github.com/jbrazio/ardufocus/compare/patch/drv8825 @NickK could you please comment ? Thanks. @swaxolez in fact there are two versions of the 28BYJ-48, the ULN2003 driver board is the same for both models. You must power the driver board either with 5V or 12V according with the motor type you have, however you should not power a 5V motor with 12V.
  10. Fresh update, yesterday I've released Ardufocus 0.1e, the main changes are: - Improvement on the stepping procedure - Both A4988 and ULN2003 driver boards now provide exactly the same functionality - Implementation of acceleration profiles: No-acceleration, Linear, Trapezoid and S-Curve See changelog since last release. Please report back any issues you may have found.
  11. Hi @stash_old, thanks for the feedback. If you look closely to the PCB, on the top right corner (which I've highlighted in red below) you'll see the footprint of an ESP01 and it's glue-logic circuitry. There are two main reasons why I'm focusing first on wired connection, 1) Field usage - People may prefer the simplicity of not carry around wireless routers or save theirs phones battery 2) Standards compliance - Every piece of equipment currently used by amateur astronomers relies in old school serial connection, people may gravitate towards it specially in mission-critical situation such as remote observatories. Some slight confusion about how temperatures are being measured. The environmental probe is a DHT22, this device is located on the main box, then each heatstrip has its own thermistors for temperature measurement. I really like your idea of cutting cables down to a bare minimum, but on the heatstrips I don't think it will work because we always have to feed in the 12V power to the heating element. Adapting existing heating elements is indeed a good idea which didn't occur to me before , maybe even having a different box type using RCA connectors instead of the GX12 ones so people have minimal effort to adapt their setup to a better controller. Something to go into my TODO list for sure. Could you please rephrase your suggestion ? I'm not understanding exactly what you meant.
  12. Let me give you an update on this project, I know last post has been long ago but it has come a long way since. All code was refactored from scratch and is now much more stable, the new development branch was not yet merged into master because there a couple of features still missing but everyone is encouraged to update the firmware to the latest release. We now have a nice GUI, as of today Windows only. The source code can be downloaded from the dedicated Github repository, pre-built binaries will be available upon the first tagged release. Until then you may compile it from source using the Visual Studio Express C#. The GUI shows you one big graph with the environmental data such as temperature, humidity and dew point. Each output has its own dedicated graph showing heatstrip temperature and setpoint. The power transistors are gone, we are now rocking FETS which makes the overall thermal footprint lower and higher energy efficiency. As you can also see I've ordered commercial grade PCB which makes the build process a breeze. On the picture is missing the Arduino Nano but it is still a key component on the system. A nice 3D printed box prototype is also under development, the following pictures are from the latest iteration. As of today there aren't yet stl files available but stay tuned, I just want to field-trip validate some small adjustments I've made before releasing them. As usual I'm open to any (good or bad) feedback. Cheers.
  13. Hi @acarrier, the problem is that the ASCOM standard (AFAIK) does not foreseen a standalone heating controller as a device type. I'm currently developing a cross-platform standalone application which will allow you to control all the parameters of the device.
  14. Actually NTC are accurate enough for the task here, what maybe happening is that the value lookup table used by Marlin to correlate the temperature with the ADC reading is not the optimal one for the type of Thermistor in use, this will make temperatures to be off (in some cases by 20, 30C) from the actual running temperature. If you have a DMM with a temperature probe is easy to validate if Marlin is setup correctly (within the error margin of the DMM, probe error, etc).
  15. It depends on brand of material but usually PLA is 190C with bed between 45-60C (depends on the size of the piece and external drafts, more temp the more mm^2 the object occupies). If you have a lot of stringing lower the nozzle temp before trying to increase retraction over 1mm.
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