symmetal

Capturing an image of the Imperial Death Star lurking nearby is more impressive. Alan

Hi R3tr0, Your replacement is certainly an improvement. There is still slight coma in the corners but whether that would bother you in real images where stacking would likely make it less noticeable only you can say. Alan

Peter, I would think a WiFi Remote Desktop solution would be a more reliable solution than the remote USB option as in the event of loss of WiFi link the remote computer carries on working. I don't know how the remote USB handles that problem. Even with a strong WiFi signal momentary signal dropouts would likely occur. You could try the compute stick and it may be better but still couldn't guarantee no dropouts. How VirtualHere copes with that situation is the main question. Alan

Peter, Didn't know you were using a USB over WiFi connection. Didn't know they existed, as USB data rates are more than Ethernet can handle let alone WiFi. For USB devices that don't send much data it could be feasible, but don't know how VirtualHere recovers with a momentary WiFi signal loss as USB would still be sending data which isn't being received and USB signal timing is rather critical. Not too well if that's what happening. I assume your problem is just a poor WiFi signal. Are you testing with the PC and Pi close to the router? I personally don't use WiFi for controlling my astro setup anymore as it's just to unreliable. When you say it worked with the computer connection coming direct you mean using an ethernet cable between them, or both wired to the router. It wouldn't be a Pi power port problem as the USB ports are powered all the time the Pi's powered. Hope VirtualHere can help you out. Alan

Craig Stark has a useful article on this The Effect of Stacking on Bit Depth Towards the end of the article he concludes that stacking even a few 8 bit images reduces the quantization noise due to bit depth considerably as long as there is some noise in the 8 bit images. (As all astro images have.) Stacking a number of 8 bit images, he found this is the equivalent bit depth of the stacked image. Stacking 10 gives a bit depth of 10.5 Stacking 50 gives a bit depth of 11.6 Stacking 100 gives a bit depth of 12.1 Stacking 200 gives a bit depth of 12.6 So at a very modest 25 fps, an 8 second video of 8 bit data will yield a stack equivalent to a 12.6 bit image. Stacking more will reduce the overall noise further but it can be seen that the quantization error caused by 8 bits quickly becomes insignificant as soon as a relatively small number of images are stacked (as long as the images contain some noise initially). I've tried taking full frame 3096x2080 pixel lunar and solar images at 8 bit (30fps) and 12 bits (15fps ) for 30 seconds each, giving 900 and 450 frames respectively and no matter how much processing I did I couldn't find any difference between them. For planetary I manage 200fps for a 400x400 pixel image so the 6000 stacked frames of a 30 sec 8 bit video makes 12 bit imaging totally unnecessary, and just uses up double the storage space (as they're saved as 16 bit videos). Alan

Peter, The motor sticking on is relay 4 not releasing. Keep your multimeter measuring DO1 o/p on the VM110 while you tell K8055_Demo to turn DO1 on and off. See if there is a voltage difference in the off state between the motor turning off and when it sticks on. Also ensure the ground connection between the relay board and the VM110 has not worked loose causing intermittent operation. Alan

Thank you for the tiff with the overlays melsky. Yes, I would certainly be happy with that. For APS-C and smaller there is no problem with the stars, at least not to me. Alan

Thanks for the pictures. The wiring thickness and construction looks fine. I see you're using a voltage stabiliser to feed power to the Eagle. This is probably putting out 12.0V irrespective of the battery voltage. If you have a bit of resistance on the connectors it could easily drop by another 0.2 to 0.5V by the time it reaches the Eagle. It doesn't look like the stabiliser is adjustable but if it is I would adjust it to give out at least 12.5V which should cure your problem. On your last photo the battery voltage is going in the bottom of the stabiliser and the stabiliser output comes out the top going via the switch and fuse to the cigar socket feeding the Eagle. Give these connections a little wiggle to check they are all tight and remove and re-seat the fuse whose contacts may have become a little tarnished as Julian said. You can measure the voltage going into and out of the stabiliser on its terminals, the voltage coming out should be no more than about 0.1V higher compared to the Eagle voltage. That's assuming the voltmeters are calibrated to read correctly which isn't always the case. Edit: The stabiliser is adjustable, as looking at this one which looks very similar, the blue potentiometer next to the output terminals, labelled CV, sets the output voltage. This is just visible on your photo. So after checking the connections are tight adjust this potentiometer until the Eagle is happy with the voltage. I would set it to read 12.5V at the Eagle and then as a check, measure the voltage at the stabiliser output terminals. This would probably read 12.6 to 12.7V which would be fine. Alan

If the voltage on the battery itself reads OK but the Primalucelab Eagle says it's too low then the wiring from the battery to the Eagle is not thick enough or one of the connections between the two is giving a poor contact. This would lead to the resistance between the battery and Eagle being too high causing excessive voltage drop. Can you post a picture of it all connected together or describe how it's done. Alan

Glad you're sorted out now John. Yes, KayFast have always given great service when I've used them. Alan

Peter, That's great that the diode on the Hall effect switch now makes it work, and on 5V too, another bonus. So all the hardware's now working. However you now have two spare opto-switches. I'm sure Hugh will be able to help you with the Lesvedome software problem you've got. Alan

Peter, Well done on getting the relays all working now. If you want to try the Hall effect switch again try putting a diode between the switch output and DI2 like I suggested a few posts ago. Also include the 10k pull up to +12V. I've repeated the drawing here. It should isolate the 12V switch from the 5V from the VM110 digital inputs, and allow the switch output to rise to 12V when it's off, similar to the function of the diode you put between DO2 and DI4. This may stop the switch from turning on as soon as you connect it to the VM110. Worth a try while you're waiting for Fedex to redeliver your opto-switch. Use one of the diodes you have, the type number isn't important. Alan

Peter, That's a good point Peter. I forgot about the connection from DO2 to DI4. That would most likely be the cause of the problem. With DO2 turning off, the voltage on DO2 should rise to close to the 12V from the relay board (DO1 does as it rises to 11.7V when off) so no current flows through the opto-led to turn on the relay. However the pull up resistors to 5V on DI4 will prevent this from happening fully, so DO2 output only rises to 8V or so allowing the opto-led to stay on by the current flowing into DI4. Putting the diode back between DO2 and DI4 means when the DO2 output turns off and its output rises towards 12V when it passes 6V or so the diode will be reversed biased and prevent current flowing into DI4. DO2 should then rise to near 12V turning off the relays 1 and 2. I should have spotted this earlier Peter. Sorry about that. Hopefully it should now all work. Alan

Peter, Those readings indicate that although the DO1 and DO2 outputs are turning on and off, the output darlington transistor pair driving DO2 output on the VM110 is sinking some current even when turned off, (much more than DO1) such that the opto-isolators on the relay board for relays 1 and 2 are passing about 0.8mA. This appears to be emitting enough light to turn on the relays. Just to test if it's the VM110 causing the problem disconnect the wire from DO1 and move the wire from DO2 to DO1. Then power it all up and run the tests again. This time when you tell DO1 to turn off and on, relays 1 and 2 should now turn off and on. If they do then the DO2 output on the VM110 is faulty. If RL1 and RL2 still stay on permanently then the VM110 for some bizarre reason can't drive two relay opto-isolators. Put the wire back to DO2 as normal but leave the DO1 wire disconnected. Remove the wire from IN2- and run the test again telling DO2 to turn off and on. If RL1 now turns off and on there is a problem with driving two relays from one output and it requires more thought. Alan

Peter, Touching the disconnected wire from DO2 to relay board DC- operating the relays means the relay board and wiring are working. When you say that applying 12V at the start relays 1 and 2 activate and stay on, that is with DO2 connected? If so it looks like DO2 output is permanently on (output low). When you did the tests filling in Hugh's table you said the Digital outputs were 0.82V or so when off and 0.68V when on. I'm assuming the wires from DO1 and DO2 were not connected to the relay board at this point or the relay board was not powered. When switched off DO1 and DO2 outputs should rise towards the relay board power rail via the opto-isolator led and series resistor. With the VM110 and relay board wired together and powered, measure the voltage on VM110 DO1 while you turn DO1 on and off with the test software. Do the same with DO2. I assume DO1 voltage goes high/low with DO1 off/on but DO2 is low/low with DO2 off/on. Is that correct? If so can you move the DO2 connection to one of the other unused DO terminals and tell the software to use that terminal instead for the motor direction signal instead of DO2. Alan

Peter, The diode protection on the IN+ inputs isn't necessary. If the power got reversed, the leds in the optocouplers would behave as zener diodes of around 5V but the 2k2 series resistor on board would limit the current so no harm would occur. The diode going to NO1, NO4 and NC2 is required as that protects the board from any reverse voltage spikes generated by the motor. Here's the diagram of the relay board. I've just shown 1 relay but the other 3 are just copies of what's inside the dotted line. I used Kicad to draw it so it's a bit neater than my scribbles. Alan

Peter, I've found the resistors going from IN+ on the relay board to +12V aren't actually needed now. I drew out the circuit of the relay board yesterday (I'll post a neater drawing later) and there is a 2k2 resistor on the board in series with the led in the opto-isolator. If you connect all the IN+ terminals you are using to +12V, the opto led will draw 4.5mA which is fine. Leaving off the resistors should make wiring easier. The encoder and UBEC grounds going to the VM110 is fine. The reverse protection diode on the battery +12V to the relay board DC+ isn't actually needed either as I've found the relay board has its own protection diode on the board. The UBEC as you say is also reverse protected so doesn't need external protection. You can leave the diode you've drawn there if you wish, as a belt and braces approach. Alan

That's just the jpeg artifacts causing the stars to have unrealistic hard edges in the image. Having random odd shaped stars with no overall trend is not an optical fault. Only the extreme left shows all the stars as being slightly similarly odd shaped which led me to imply slight coma there but it's not definite due to the jpeg compression. If Mel can post a tiff or png we can give a more accurate assessment. Alan

Peter, Unlucky that you ordered the wrong opto-switch at first. Isn't that always the way. A buck converter is a good option to get your 5V instead of the Pi USB cables. I think that was mentioned at the start of this thread. Your UBEC is a buck converter under a different name. (I had to google what it was, Universal Battery Eliminator Circuit used in RC models). That would be fine to use if you didn't want to spend a few pounds on one from eBay. There's no need for the toroid in the output lead of the UBEC in your case as you don't need to worry about receiver interference, unless you specifically want to use the output connector as it is. You can use it to power the encoder and the opto-switch as you say. Alan

Hi Mel, Your RedCat image is the best I've seen at the moment regarding star shapes particularly as it's full frame. There looks to be a hint of coma down the extreme left but it's very small and you wouldn't notice it unless you were examining pixels. It's hard to tell exactly as the jpg artefacts distort the star edges to some degree. If I had that one I'd be happy. For an APS-C or smaller sensor it would be look to be excellent. Alan

Peter, Regarding the photo-sensors you mentioned the 10V Power supply voltage and 28V output voltage are the maximum values you can use, voltages below this will be fine. The data sheet doesn't specify a minimum power voltage but I'm sure it will work from 5V. The three wires are the same as the Hall effect switch so can be a direct replacement. The difference between the two sensors is the 3009 is 'on' when it's dark while the 4009 is 'off' when it's dark. For your application where the bracket on the dome blocks the light path in the home position the 3009 mimics the effect of the Hall effect switch (if it worked) or reed switch. Hugh can give you a more informed answer. If you wanted to power it from 12V you could put a resistor in the power lead to the photo-sensor, around 330R which should drop the voltage at the power terminal to about 6V. Alan

The encoder readings are fine so no problem there. You can't use the Analog Inputs as a 5V source as they are, as there is a 1k resistor between 5V and the Analog Input terminals. With the encoder drawing 28mA this resistor would drop 2.8V so only 2.2V would be left for the encoder. If you didn't want to solder a wire directly to SK2 or SK3 to obtain 5V you could short out the 1k resistors (R12 and R13) with a link of wire on the rear of the board and plug jumpers into SK2 and SK3. Then you would have a proper 5V on the two Analog input terminals. I would go with the optical switch suggested by Hugh in place of your Hall effect switch as you know that would work. I did receive the relay board like yours so I can test it with or without resistors to find optimum values. Have you used 1k resistors connected to the IN+ terminals as my recommendation several posts ago. You did say at the time you had forgotton to change the drawing from 5k to 1k on your last drawing post but were going to use 1k. Alan

As James says ebay is useful for small numbers of screws. KaysFasteners are very good, giving quick free delivery. Scroll down the left column to see the UNC and UNF fixings (and any other type ) Alan

Peter, Reading the data on The Digital Inputs of the VM110 they are are not simple 5V hi/lo inputs, but darlington transistors. This explains why the voltage you measured from the Bourns Encoder was only 2.79V and not 5V. The Encoder output is effectively open circuit for a high and switches to ground for a low so the measured VM110 Digital input voltage is determined by the current supplied by the input pull-ups to turn on the darlingtons. About 2.7V is the minimum voltage to turn on the darlingtons which is what you measured for an encoder high o/p. The VM110 input darlingtons are on (high) normally, sitting around 2.7V, so all you can do to change the inputs is by shorting them to ground or by a resistor to ground up to around 10k. The Hall effect switch output (by the information sheet) is the same as the encoder, open circuit for a high and 'shorted' to ground for a low. However it doesn't seem to be that way (open collector) by the way it behaves. The fact that you measured 9V on Digital input 2 with the 10k pull up to 12V dropping to 8.72V when you pressed SW2 (which connects the input to ground via 10k) means the Hall effect switch output wasn't on (low) even though the led indicated it was. Your test with the second Hall effect switch had the output at 2.84V (close to open circuit input voltage) when connected to the VM110 so the switch again wasn't on I'm at a loss at the moment as to what to suggest next with this Hall effect switch as it doesn't behave as it should. I didn't imply you could run the switch off 5V in my previous post as it's rated at 6V minimum though it may work from 5V. It can't be any worse than using 12V at the moment. 5V isn't available on the VM110 terminals but you can get 5V from one of the pins of the jumpers SK2 and SK3 next to RV1 and RV2, which you aren't using. See diagram below. You can use this to power the encoder instead of the usb lead. Also try the Hall switch off the other 5V too if you wish. Alan

Peter, If the Hall effect works with the 10k external pull up it's preferable to include a diode as shown below. This prevents the 12V power supply from trying to feed 0.2mA into the 5V power supply which isn't good practice. I've just used a commonly used general purpose signal diode but any similar diode will do. Alan