Gina

I also seem to be having a problem with the remote focussing, which was working fine yesterday. I think the top cone which is attached to the lens and rotates with it may be catching on the main casing. I might make a new one with more clearance.

Rain has stopped and the clouds are clearing but the only things visible are a bright moon, reflections from it in the lens and terrestrial objects! No chance of seeing any stars! At least, not unless a dark cloud covers the moon.

The datasheet for the IRLZ44N shows the transfer graph as Vgs being well under +3v for turning on with a few amps drain current but I have two samples and both show turning on fully at around +3.2v Vgs. If you know of any that switch at a lower Vgs Neil, I'd like to know. Obviously I would like to keep things as simple as possible.

I've tested some logic level power MOSFETs (IRLZ44N) and they needed +3.2v to turn on. The RPi produces about this or slightly less - rejected on reliability grounds.

Raining again!!!

BBC Weather forecasts clear for most of the night tonight but Clear Outside is not so promising. Also strange with Clear Outside is that it shows 100% moon yet show tomorrow as Full Moon with 99%. But in any case the moon is up for the whole night so I don't expect to see many stars even if the cloud stays away.

Actually, the rain stopped and the sky cleared a bit just before midnight and I was able to capture an image a couple of seconds before midnight and another 3m into 2018. There are a few raindrops on the lens. HAPPY NEW YEAR everyone

This is probably the last image of 2017 as it's raining now.

GPIO assignments. // Lens Cover Motor Hall Switches #define IN1 RPI_BPLUS_GPIO_J8_29 // GPIOO5 Open #define IN2 RPI_BPLUS_GPIO_J8_31 // GPIO06 Closed // Lens Cover Motor #define IN1 RPI_BPLUS_GPIO_J8_16 // GPIO23 DIR #define IN1 RPI_BPLUS_GPIO_J8_18 // GPIO24 STEP #define SLEEP RPI_BPLUS_GPIO_J8_22 // GPIO25 SLEEP This code steps the motor once and will be included in a loop together with the step count and Hall sensor test. // step on bcm2835_gpio_write(STEP, HIGH); // wait bcm2835_delay(STEP_DELAY/2); // step off bcm2835_gpio_write(STEP, LOW); // wait bcm2835_delay(STEP_DELAY/2); Testing the Hall sensors is simply if (bcm2835_gpio_lev(Hopen) == LOW ) Where Hopen specifies the GPIO pin for the OPEN sensor, and similarly for the CLOSED sensor. Status Lights :- Grey IPS_IDLE Yellow IPS_BUSY Green IPS_OK Red IPS_ALERT

Printed and added the top dome to the lens cover and cleaned it up. Printed in opaque ASA this seems to let a negligible amount of light through so I think it will be suitable for taking darks, at least at night, as well as keeping rain out when closed. The next job is to write the code that controls the stepper motor that opens and closes it.

Raining again so had to bring the ASC in. If it clears up later I'll pop it back out an see if I can capture some stars. I need to get the lens cover motor working and all the code set up appropriately.

Now have the casing on and ASC on the pole and hooked on the guttering.

Now have the buck converter in use and single 13.8v supply from bench PSU.

Focussing on a terrestrial view is made difficult because of the narrow depth of field with this very wide lens. I have attempted best focus on the trees in the middle distance as the far hills are too misty. It should be easier at night with nice pinpoint stars (or even the moon). A variation of 50 ticks in the focuser is noticeable so the scale seems quite reasonable. This corresponds to a few degrees of rotation of the lens. Power is now from a single bench PSU using the buck converter. I havn't fixed the Wi-Fi yet - this is working with wired LAN. Here are a couple of images - screenshots from the KStars FITS Viewer.

Took the HAT and inserted a new A4988 stepper motor driver then plugged the HAT onto the RPi and connected separate power supplies for the RPi and motor driver (13.8v) and commoned the Gnd connections. Powered up and waited for everything to load then connected over LAN and re-compiled the Astroberry DIY driver for focuser. Ran the indiserver command on the RPi followed by KStars/Ekos INDI startup on the client machine and everything worked That includes the remote focussing I do not yet have anything installed for the dew heater or camera cooler controls.

Added HAT to RPi and stepper motor driver for remote focussing, started up RPi and re-compiled the Astroberry DIY driver for focus only. Then ran gina@asc:~$ indiserver -m 100 -vv indi_asi_ccd indi_rpifocus In KStars/Ekos started INDI and got everything running. Remote focussing is working Currently using separate power supplies for the RPi and motor driver but I'll connect to the buck converter and run everything from one PSU shortly - I'm taking one step at a time due to the problems I've been having.

Maybe tomorrow evening might be clear according to the forecast. I'm not quite sure about the remote focussing, might have to increase the downwards pressure to hold the lens straight. Won't really know until I get it up on a mast outdoors. Not that I've got remote focussing working yet! Pouring with rain ATM

Screenshot of image as seen in KStars FITS Viewer. Just started to rain again so had to close window. Two raindrops on lens. ASC on window sill just inside.

I'm not using PWM, just ON/OFF control but when I used PWM with other imaging rigs I made up my own filters with a ferrite ring and several turns of wire plus a ceramic capacitor.

Dew heater control with optocoupler.

I think the HAT is usable, I've moved the connections on the second driver to good positions and cleared the area where the circuitry for the dew heater and camera cooler controls were located.

Been reading the book I have on interfacing the RPi and it seems advisable to use optocouplers so I've ordered 10 off EL817 Optocoupler from Amazon with Prime delivery Wednesday. Best I can do with the dreaded bank holidays! Further very close examination of the HAT has shown broken connections on the second stepper driver module so I've moved the connections onto good ones GPIO23, GPIO24 and GPIO25. // Lens Cover Motor #define IN1 RPI_BPLUS_GPIO_J8_16 // GPIO23 DIR #define IN1 RPI_BPLUS_GPIO_J8_18 // GPIO24 STEP #define SLEEP RPI_BPLUS_GPIO_J8_22 // GPIO25 SLEEP

Further closeup examination of the HAT has shown that several of the connections to the GPIO pins are broken. The no.2 stepper driver will not work anyway. The tops of the feed-through holes have come away. It would seem that these HATs are unsuitable for modifications - if you don't get it right first time, throw it away!! I think I have one or two multi-way cables that fit the GPIO pins so maybe I can separate the wires and solder them to a stripboard for I/O.

Not going to do that - I'm not going to input current into a GPIO pin even from the GPIO +5v line. Been reading the book I have on interfacing the RPi and it seems advisable to use optocouplers so I've ordered 10 off EL817 Optocoupler from Amazon with Prime delivery Wednesday. Best I can do with the dreaded bank holidays! These can drive the MOSFETs.

For a start the Peltier TEC is not 20W at 5V it draws about 0.5A at 5v = 2.5W. With this and the dew heater one of the IRLZ44Ns switched on at about 3.2v and it was totally off at 2v. So a range of 1.2v goes from off to on. 3.2v is too close to RPi logic 1 to be reliable but a voltage divider to +5v or a resistor and diode to 5v would make a reliable circuit I reckon.