My New Favorite Tool

Phil Pilgrim (PhiPi)

When I receive TSL1401-DB circuit boards from the assembly house, there's still a little work to do. They do all the soldering, but I still do the mechanical assembly, testing, and packaging. The mechanical assembly seemed like it was taking way too long, and I suspected it was because of screwing the lens holder to the PCB, which I did with a manual screwdriver. On a recent trip to the hardware store, I asked about electric screwdrivers and ended up buying a petite Black and Decker cordless model that uses a lithium ion battery. (Yeah, I know: It'll be charged in the house. If that burns down, too bad. But if the shop ever burnt down, loop abort; program end.) What a difference! Assembly goes so much faster now. And, as the TSL1401-DB seems to be gaining in popularity (it was even used in that amazing Turing machine) and demand for it increases, that's important.

Anyway, here's a photo of my assembly workstation:



The test fixture is a MoBoStamp-pe with a custom daughterboard having some indicator and illuminator LEDs, along with a test button and a target for the sensor to look at. I plug in the board, press the button, the illuminator LEDs come on, a test is run, and the indicators light up green or red to indicate success or failure. If success (so far, so good), it goes into the bag, which gets sealed with a bag sealer that's just out of view. BTW, PBASIC makes coding a test fixture like this a piece of cake. The TSL1401-DB test program probably took all of an hour to write and debug.

Back to the screwdriver: for $39 it does not have a torque-limiting clutch. They had another model that had one, but it was bigger and more expensive. My experience with a Makita drill/driver that has a clutch pretty much soured me on clutches designed for home workshop use. I stripped way too many screws when relying on it. So I decided my own wrist was probably more accurate than some cheap mechanical gizmo. So far, I think I've been right. Someday, maybe, I'll have adequate justification to get one of these:

www.amazon.com/Sumake-Screwdriver-ED-6001PS-Automatic-precision/dp/B000G96EM8

Mmmmmm! Precision!

-Phil

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Post Edited (Phil Pilgrim (PhiPi)) : 3/31/2010 5:26:14 AM GMT

Erik Friesen

That looks like a handy tool.

It seems like my favorite tool moves from thing to thing.

A have two or three new favorite tools.

A hakko 936 www.kimcodistributing.com/store/item.asp?DEPARTMENT_ID=461&ITEM_ID=7&gclid=CJT89LSV46ACFSQ5gwodI1f9Ag partly because it gets hot in about 30 seconds.

These Wiha tweezers www.mouser.com/ProductDetail/Wiha/44501/?qs=IKkN%2f947nfAaFOtdLStPMA%3d%3d and www.mouser.com/ProductDetail/Wiha/44510/?qs=IKkN%2f947nfDZqNP2OZCPRw%3d%3d I had always been skeptical about these $25 tweezers until I bought one.

Another tool I have is a hand assembly board sort of like the jpg that I really like for smt work. It keeps my hands out of the paste.

John R.

I purchased the Milwaukee Electric Tool version of the "mini-driver" and have been happy with it, and had good success with the clutch.

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John R.
Click here to see my Nomad Build Log

Tracy Allen

I meant to post this earlier on the topic of handy screwdrivers. This one is homemade, for working with the small screws on the green Phoenix terminals shown in the photo. In the course of making and testing breakout boards, we have to tighten or loosen hundreds of these contacts. Hand screwdrivers are out of contention, and most electric screwdrivers I have seen are too big, too powerful. This small DC motor runs from an adjustable LM317 in the box, set to give just the right torque. Usually we run it at about 2.5 volts and it draws about 10 mA, and much more when starting or stalled. The box has a DPDT reverse switch, and the push button hacked onto the outside of the motor is the trigger. We can run down a row of terminals really fast now. The hardened blade is cut off from one of those nice Wiha screwdrivers, and joined to the motor shaft with an epoxy filled tube, and outside that a length of adhesive line heat shrink tubing.


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Tracy Allen
www.emesystems.com

Chris Savage

It's always inspiring to see people who make their own tools and test equipment.

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Chris Savage

Parallax Engineering
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sam_sam_sam

I purchased the Milwaukee Electric Tool version of the "mini-driver" and have been happy with it, and had good success with the clutch.

I have one my self

Make sure that you do not loose the sale slip

It was just about a year and the battery would not take a full charge so I had to get them replaced

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·Now wanting to learn Spin· Thanks for any··that you may have and all of your time finding them

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Sam

Peter Jakacki

Tracy Allen said...
I meant to post this earlier on the topic of handy screwdrivers. This one is homemade, for working with the small screws on the green Phoenix terminals shown in the photo. In the course of making and testing breakout boards, we have to tighten or loosen hundreds of these contacts. Hand screwdrivers are out of contention, and most electric screwdrivers I have seen are too big, too powerful. This small DC motor runs from an adjustable LM317 in the box, set to give just the right torque. Usually we run it at about 2.5 volts and it draws about 10 mA, and much more when starting or stalled. The box has a DPDT reverse switch, and the push button hacked onto the outside of the motor is the trigger. We can run down a row of terminals really fast now. The hardened blade is cut off from one of those nice Wiha screwdrivers, and joined to the motor shaft with an epoxy filled tube, and outside that a length of adhesive line heat shrink tubing.

Now that's engineering! As we say here in oz "Good on ya!"

I did modify a pcb drill once to idle slowly and then sense the load and speed up as you pushed into pcb after which it would go back to slowly idling, saves having to turn it on and off. Could you do something similar to the screwdriver? Maybe even just a switch on the back of the motor so as you pressed it would run or the harder you pressed the more torque it would provide?

I have an assortment of motors, some geared, lying around the place that I could adapt into a terminal screwdriver too, good idea. With a controller the slowly idling blade would automatically lock into the screw head and then speed up (with current limits) until it stalled so it could just idle back again and wait for release to reset it. No need for a switch then.

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*Peter*

mikediv

Tracy very cool,,, Phil I never had any luck with Black and Decker the batteries always crapped out after 5 minutes ,,That one you posted could be very useful to me but can I ask what kind of battery life do you get out of it are you happy with how long the run time is?

Phil Pilgrim (PhiPi)

I'm getting much better life out of the B&D Li-ion batteries than I ever got with my Makita NiMHs. Of course, the Makita came with a pair of battery packs that could be swapped out, so one could be used while the other was recharging. The major difference for me has been better shelf life with the Li-ions without the self-discharging that plagues NiMH batteries. The B&D can go for weeks without use and without losing charge. I've only recharged the B&D unit once since I got it; but, even then, it wasn't flagging by any means.

-Phil

Tracy Allen

I thought too about adding features to the micro-screwdriver, but when it came right down to it, the KISS version met 99% of expectations. When running down a row of terminals, the screwdriver comes in spinning fast, but with a little technique it instantly finds the slot in the screw and starts turning. The torque at stall is nowhere near enough to over-tighten or much less strip the threads. If anything I would add a boost switch that would hammer with a repeating pulse when it detects a stall.

With regard to Black & Decker, I have a couple of dead ones here too, due to misplacing or mixing up the power adapters. I should remember to label both the adapters (which device does it belong with?), and on the screwdriver (what are the ratings of its charger?).

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Tracy Allen
www.emesystems.com