New hot end board: pre-order yours now!
Posted by dc42
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Re: New hot end board: pre-order yours now! May 30, 2014 02:59PM |
Quote
dc42
The printed parts needed are:
1. Modified heatsink duct, or modified version of Matt's one-piece heatsink/fan duct....
..or johneato's Control air to the nozzles version, have used it with your kit 5 since started ABS printing, I think its great!
[forums.reprap.org]
Erik
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Re: New hot end board: pre-order yours now! June 10, 2014 08:03AM |
A few updates:
1. Thanks for all the provisional orders. As there are nearly 30 of them, I haven't acknowledged them all individually. I will send payment requests via PayPal when the boards are nearing completion, which should be near the end of this month.
2. We finally had a sunny day here, so I tested the effect of sunlight shining on the bed. The only way I could get the sensor to saturate was by removing the sensor board from the hot end, holding it a few mm above the bed, and rotating it so that the area of the bed directly under the sensor was not in the shadow of the board or anything else. This is in contrast to the TCRT1000 sensor used in my previous board and RRPs board, which saturates much more easily. I also tested it with a 60W incandescent light, and I had to move the bulb to within 5cm of the bed and sensor head to get it to saturate.
So the differential IR sensor is even more resistant to sunlight and other ambient IR than my previous board, which was already nearly 100 times less sensitive to it than RRP's unmodulated board. About the only way I think you could get it to saturate in real use is with strong sunlight falling on the bed at a shallow angle. If the sensor does saturate, it signals this by giving a z-probe reading of 1023 to alert you.
3. The bare PCBs have been manufactured and are on their way to me. I have ordered 100 PCBs, and I will get 50 of them assembled initially.
4. Here are some scope traces of the signal from the phototransistor, showing how the 3-way modulation works. First, with the sensor above the target height and returning a G31 reading of zero:
:
The base level is with both LEDs off, so it is the response to ambient IR. The shoulder is the response to reflected light from the LED closest to the phototransistor. The peak is from the LED farthest from the phototransistor, showing a strong reflection from the surface of the bed.
Next, when the sensor has detected that it is approaching target height and set the G31 reading to 441 (so that the Duet knows to slow down the z motor):
The reflection from the far LED has reduced a little, and the reflection from the near LED has almost caught up with it.
Now the Goldilocks moment, the reading has just jumped to 576:
Both reflections are of equal intensity.
Finally, with the sensor too low, still reading 576:
Now the far LED is reflecting much less strongly, and the near one strongly.
Edited 1 time(s). Last edit at 06/10/2014 08:04AM by dc42.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
1. Thanks for all the provisional orders. As there are nearly 30 of them, I haven't acknowledged them all individually. I will send payment requests via PayPal when the boards are nearing completion, which should be near the end of this month.
2. We finally had a sunny day here, so I tested the effect of sunlight shining on the bed. The only way I could get the sensor to saturate was by removing the sensor board from the hot end, holding it a few mm above the bed, and rotating it so that the area of the bed directly under the sensor was not in the shadow of the board or anything else. This is in contrast to the TCRT1000 sensor used in my previous board and RRPs board, which saturates much more easily. I also tested it with a 60W incandescent light, and I had to move the bulb to within 5cm of the bed and sensor head to get it to saturate.
So the differential IR sensor is even more resistant to sunlight and other ambient IR than my previous board, which was already nearly 100 times less sensitive to it than RRP's unmodulated board. About the only way I think you could get it to saturate in real use is with strong sunlight falling on the bed at a shallow angle. If the sensor does saturate, it signals this by giving a z-probe reading of 1023 to alert you.
3. The bare PCBs have been manufactured and are on their way to me. I have ordered 100 PCBs, and I will get 50 of them assembled initially.
4. Here are some scope traces of the signal from the phototransistor, showing how the 3-way modulation works. First, with the sensor above the target height and returning a G31 reading of zero:
The base level is with both LEDs off, so it is the response to ambient IR. The shoulder is the response to reflected light from the LED closest to the phototransistor. The peak is from the LED farthest from the phototransistor, showing a strong reflection from the surface of the bed.
Next, when the sensor has detected that it is approaching target height and set the G31 reading to 441 (so that the Duet knows to slow down the z motor):
The reflection from the far LED has reduced a little, and the reflection from the near LED has almost caught up with it.
Now the Goldilocks moment, the reading has just jumped to 576:
Both reflections are of equal intensity.
Finally, with the sensor too low, still reading 576:
Now the far LED is reflecting much less strongly, and the near one strongly.
Edited 1 time(s). Last edit at 06/10/2014 08:04AM by dc42.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Re: New hot end board: pre-order yours now! June 19, 2014 09:30AM |
Here is a quick update. I have just assembled two pre-production boards:
I'll test them this afternoon, then if all goes well I shall place the order for 50 to be assembled.
I already have provisional orders for 31 boards, so there are 19 more available from the first batch.
The draft installation instructions are at [miscsolutions.wordpress.com] although some of the photos need to be updated.
Edited 2 time(s). Last edit at 06/19/2014 09:32AM by dc42.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
I'll test them this afternoon, then if all goes well I shall place the order for 50 to be assembled.
I already have provisional orders for 31 boards, so there are 19 more available from the first batch.
The draft installation instructions are at [miscsolutions.wordpress.com] although some of the photos need to be updated.
Edited 2 time(s). Last edit at 06/19/2014 09:32AM by dc42.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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Re: New hot end board: pre-order yours now! June 20, 2014 03:22AM |
The pre-production boards are working well and I have placed the order for manufacture. I should have the boards ready to test and ship about 2 weeks from now.
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod
Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].
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