Idea for automatic jumper placement - Page 1
Forum section: electronics / general

author: pisoiu
author_rank: Regular Contributor
timestamp: March 22, 2019, 10:22:38 am
content: Hi,I have in one of my designs several 3x2 dual pin headers, 1.27mm, to connect and route various signals across the board. The headers are SMT, come in reel, are assembled automatically at smt line. But the jumpers used to make the actual connection as desired, come in bag, they cannot be processed by pnp machine. And they must be installed later, after reflow, anyway. For now I have no other way than to install them manually, one by one. Major PITA, they are many and they are small.Can anyone give me an advice to speed up this process? I cannot use other form of connectors due to space and cost constraints. Manufacturer does not have a solution for this, I asked.Thanks.https://katalog.we-online.de/en/em/PHD_1_27_SMT_DUAL_PIN_HEADER_REEL_6213XX21021/S/62130621021?m=n&sq=62130621021&sp=https%3A%2F%2Fwww.we-online.de%2Fweb%2Fen%2Felectronic_components%2Fsearchpage_PBS.php%3Fsearch%3D62130621021&_ga=2.90228058.1723596626.1553204965-623606181.1545381407https://katalog.we-online.de/en/em/PHD_1_27_JUMPER_1X2_62200213421/S/62200213421?m=n&sq=62200213421&sp=https%3A%2F%2Fwww.we-online.de%2Fweb%2Fen%2Fwuerth_elektronik%2Fsearchpage.php%3Fsearch%3D62200213421&_ga=2.87188696.1723596626.1553204965-623606181.1545381407

author: SWR
author_rank: Regular Contributor
timestamp: March 22, 2019, 11:04:25 am
content: Maybe this one is too obvious to be useful?: replace jumpers with SMD DIP switch.

author: ar__systems
author_rank: Frequent Contributor
timestamp: March 22, 2019, 11:20:38 am
content: Replace them with 0 Ohm resistors.

author: pisoiu
author_rank: Regular Contributor
timestamp: March 22, 2019, 11:54:41 am
content: I thought at smd dip, but they are too big and too expensive. And I do not have the flexibility of jumpers. DIP switch is 1p1t per 2 pin, I can use them just on/off. Jumpers are 1p2t per 3 pin, I can use them as a selector. To obtain functionality of one 3 pin header I must use 2 separate dip switches.0 ohm not good, jumper settings must be available to be modified by user.

author: nisma
author_rank: Regular Contributor
timestamp: March 22, 2019, 02:01:36 pm
content: If you use the jumpers on break away headers you could place 10 at same time on PCB. From this the PNP with gripper nozzle can feed it and place it to needed pos. Each assembly must have two local fiducials, the pin header itself and for this you need a PNP that is able to use pins as fiducial, many can do it, not all. PNP with coaxial lightning don't work.

author: Gribo
author_rank: Frequent Contributor
timestamp: March 22, 2019, 02:02:34 pm
content: 74HC245? Analog switches? What sort of signals are you routing? Consider the cost of a 1.27mm header + jumpers + your time vs the cost of a dip switch.Also,https://www.digikey.com/products/en/switches/dip-switches/194?k=&pkeyword=&sv=0&pv7=2&pv7=243&pv7=1&sf=0&FV=1f140000%2Cffe000c2%2C2080002&quantity=&ColumnSort=0&page=1&pageSize=500

author: pisoiu
author_rank: Regular Contributor
timestamp: March 22, 2019, 02:16:45 pm
content: Yes, I considered the time. Unfortunately, analog switches don't work.One jumper for example is used to connect CAN terminator across canh and canl, if desired. I cannot use analog switch on that, it will create problems with protection on CAN bus.Other is a selector for a connector signal, it can route it to a power supply (must source 1A of current), or route it to a pull-down transistor to activate various loads (relays, etc), etc.Others are connector signal switches between rs232 signals and generic ios which can have anywhere between 0-40V.

author: nisma
author_rank: Regular Contributor
timestamp: March 22, 2019, 04:15:51 pm
content: do you have you'r own pnp or not ?

author: pisoiu
author_rank: Regular Contributor
timestamp: March 22, 2019, 05:42:42 pm
content: I don't have it yet. Maybe later this year, but it is not sure, there are a lot of bureaucracy issues, mostly about the environment, to be solved.But this issue is not really related to who assembles the design.Wurth offers headers in reel to be used by pnp machine but jumpers are loose, they cannot be manipulated automatically. They also do not offer tools for that.I thought maybe somebody is aware of other manufacturers who offers 1.27mm jumpers in some form which allows pnp machine to use it. I searched as far as I could but found nothing.

author: nisma
author_rank: Regular Contributor
timestamp: March 22, 2019, 06:27:37 pm
content: I know headers that are flat and close on top to be manipulated and this are available as breakaway header. If the assembler don't have a gripper nozzle you must print the tray for this. You place 10 at the same time for filling the feeder. Hovewer the used PNP must be able to use pin header as part fiducial.

author: pisoiu
author_rank: Regular Contributor
timestamp: March 22, 2019, 06:33:35 pm
content: That's a great idea, thanks.

author: gamalot
author_rank: Super Contributor
timestamp: March 22, 2019, 06:33:55 pm
content: There are SMD headers with pick cap.

author: SWR
author_rank: Regular Contributor
timestamp: March 22, 2019, 07:51:32 pm
content: Quote from: pisoiu on March 22, 2019, 11:54:41 amWhich currency are you using here?I have attached an AliExpress switch with 12 poles for $0,23.Maybe there are better offers out there?CAN terminator requires a single switch.Connector signal to a power supply requires a single switch.Pull-down transistor to activate loads requires a single switch.Switching between rs232 and generic I/O might be done with a single switch?- Place switch in series with RS232 driver output to disconnect it.- Place large resistor from RS232 driver input to switch output.- If switch is closed the RS232 driver will override the resistor.- If the switch is open the resistor will override the RS232 driver.- The resistor must be large enough to limit the over voltage current into the input at maximum input voltage.- Otherwise you need additional schottky diode protection on the input.