dwell reducer circuit for toyota COPs
#62
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Ok, here is my contribution to the thread.
I've taken JasonC's original design and, while keeping all the same reference designators and the basic layout, added space for two multi-turn potentiometers. The idea is that those who have access to a scope should build the board with the two pots R20 and R21, but without R2, R10, R15 and R16. I'd suggest anywhere from a 20k to a 100k pot, depending on the magnitude of dwell reduction required.
Those who do not have a scope should omit the two pots, and install the four fixed resistors using known-good values. Apparently different year Miatae had different factory dwell, so over time I assume we'll be able to put together a table of appropriate resistor values. Additionally, I provided four mounting holes for 4-40 screws, so you can install this in an enclosure if you wish.
I've drawn the schematic and board layout in the ExpressPCB software. The advantage to doing this is that any of you can download my design, download and install the ExpressPCB application for free, and order your own board(s) directly.
The design is optimized to be ordered via their 2-layer "Standard" service. This will get you boards with a high-quality silkscreen and soldermask, just like a "Real" PCB. Basically, the same quality as you'd expect from a commercial circuit board.
There is obviously a huge savings to ordering multiple boards in one run, but I'm going to let someone who cares handle that. I'm not going to do the actual buying because I don't need one. Assuming that service is selected, here's how the cost will break down:
Qty 2 = $76 ($38 each)
Qty 4 = $83 ($20.75 each)
Qty 6 = $90 ($15 each)
Qty 8 = $96 ($12 each)
Qty 10 = $103 ($10.30 each)
Qty 12 = $110 ($9.17 each)
Qty 14 = $117 ($8.36 each)
Qty 16 = $124 ($7.75 each)
...and so on...
I strongly advise that someone should double-check my work before ordering anything, as quite frankly I'm tired and starting to see double.
Here are the schematic and layout in graphical form. The actual design files are attached as a ZIP.
I've taken JasonC's original design and, while keeping all the same reference designators and the basic layout, added space for two multi-turn potentiometers. The idea is that those who have access to a scope should build the board with the two pots R20 and R21, but without R2, R10, R15 and R16. I'd suggest anywhere from a 20k to a 100k pot, depending on the magnitude of dwell reduction required.
Those who do not have a scope should omit the two pots, and install the four fixed resistors using known-good values. Apparently different year Miatae had different factory dwell, so over time I assume we'll be able to put together a table of appropriate resistor values. Additionally, I provided four mounting holes for 4-40 screws, so you can install this in an enclosure if you wish.
I've drawn the schematic and board layout in the ExpressPCB software. The advantage to doing this is that any of you can download my design, download and install the ExpressPCB application for free, and order your own board(s) directly.
The design is optimized to be ordered via their 2-layer "Standard" service. This will get you boards with a high-quality silkscreen and soldermask, just like a "Real" PCB. Basically, the same quality as you'd expect from a commercial circuit board.
There is obviously a huge savings to ordering multiple boards in one run, but I'm going to let someone who cares handle that. I'm not going to do the actual buying because I don't need one. Assuming that service is selected, here's how the cost will break down:
Qty 2 = $76 ($38 each)
Qty 4 = $83 ($20.75 each)
Qty 6 = $90 ($15 each)
Qty 8 = $96 ($12 each)
Qty 10 = $103 ($10.30 each)
Qty 12 = $110 ($9.17 each)
Qty 14 = $117 ($8.36 each)
Qty 16 = $124 ($7.75 each)
...and so on...
I strongly advise that someone should double-check my work before ordering anything, as quite frankly I'm tired and starting to see double.
Here are the schematic and layout in graphical form. The actual design files are attached as a ZIP.
#63
Joe, add an NPN emitter follower to each output using a 2N3904 or 2N2222 NPN transistor. This way you can use a much more commonly available rail to rail CMOS opamp (MC30xxx, can't remember the p/n). Place it between the opamp output and the 100Ω resistor.
The delay is roughly inversely proportional to the value of the resistance across the diode. If you have a pot there, just place a small resistor in series to set the minimum R and don't bother with parallel resistors. The trouble with pots is their reliability - you have to use something like one of those Bournes blue and white plastic lay down types to get decent reliability.
Does your PCB software not check connectivity?
The delay is roughly inversely proportional to the value of the resistance across the diode. If you have a pot there, just place a small resistor in series to set the minimum R and don't bother with parallel resistors. The trouble with pots is their reliability - you have to use something like one of those Bournes blue and white plastic lay down types to get decent reliability.
Does your PCB software not check connectivity?
#71
If anyone wants these complete plug and play I need 10 people interested, and unfortunately I'm a newb on the forums so you can't PM. Just post here, and letme know. I have a guy whose going to make the first couple for free so we can test out the boards. I don't have the equipment to test them and we would need someone to do the test part as well to make sure the larger run is going to go ok. I only have one person interested so far, and we could have the test boards by next wed if there is enough interest.
Last edited by TravisR; 06-19-2008 at 06:42 PM.
#72
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If anyone wants these complete plug and play I need 10 people interested, and unfortunately I'm a newb on the forums so you can't PM. Just post here, and letme know. I have a guy whose going to make the first couple for free so we can test out the boards. I don't have the equipment to test them and we would need someone to do the test part as well to make sure the larger run is going to go ok. I only have one person interested so far, and we could have the test boards by next wed if their is enough interest.
#76
POPSTOY4WBJT_Gerber.ZIP (43.3 KB, 14 views)
Jason,
Yea I used this Gerber, I didn't see mounting holes on the boards. Which gerber file are the holes located in? Also, do you have any idea on where I can find some adapter that would fit or I could rig to fit the stock connector so people could simply plug and play. I have been searching digi key for a while now and have come up blank.
Travis
Jason,
Yea I used this Gerber, I didn't see mounting holes on the boards. Which gerber file are the holes located in? Also, do you have any idea on where I can find some adapter that would fit or I could rig to fit the stock connector so people could simply plug and play. I have been searching digi key for a while now and have come up blank.
Travis
#79
Alright guys somehow the signals got crossed on how many I wanted on the first batch, and I think I'm getting about 40 of these PCB's. I'll have to see about cost. If you don't want them assembled i can pass them on for pretty cheap. If you want them assembled... Well they'll still be pretty cheap. If you want them in a pretty box, with connectors and plug & play you'll have to wait a bit longer & pay a bit more. I still haven't found an easy way to hack the adapter. Visit my website and pop me an email in the contact section if you want in on this. I'm out of town right now and can't respond to email, or setup the webpage to have an official order spot or anything. www.boundaryengineering.com
Also no serious obligations here until we find it does work perfectly I just want a number interested so I can get a quote on the first batch assembled. I can't test this part and I don't even need a convertor as I have an adjustable dwell standalone. These are just for you guys! Can someone with the know how and the time to test Jason's work plz plz send me an email so we can get these boards certified as a working part. I really don't want to ship these until we know for sure.
T
Also no serious obligations here until we find it does work perfectly I just want a number interested so I can get a quote on the first batch assembled. I can't test this part and I don't even need a convertor as I have an adjustable dwell standalone. These are just for you guys! Can someone with the know how and the time to test Jason's work plz plz send me an email so we can get these boards certified as a working part. I really don't want to ship these until we know for sure.
T
#80
Quote:If you want them assembled... Well they'll still be pretty cheap. If you want them in a pretty box, with connectors and plug & play you'll have to wait a bit longer & pay a bit more. I still haven't found an easy way to hack the adapter.
TravisR this site has a lot that may help. I got my pretty box here.
http://www.bgmicro.com/index.asp?Pag...S&Category=316
I bought all my stuff here and at digi-key.
Hope this helps. I trying to build the first edition PCB and dwell device.
Lee
TravisR this site has a lot that may help. I got my pretty box here.
http://www.bgmicro.com/index.asp?Pag...S&Category=316
I bought all my stuff here and at digi-key.
Hope this helps. I trying to build the first edition PCB and dwell device.
Lee