Have you ever had a faulty and/or broken device and found yourself thinking "what can i recover from this (s)crap"? It happened to me several times, and while i was able to reclaim most part of the hardware i wasn't able to reclaim most part of the electronics components. The issue wasn't about desoldering them, but to identify them instead. Not to mention the even more important check of their working status.
There are numbers of different projects that are supposed to convert an arduino into a component tester and i'm sure that they can do what they are promising, but i guessed why should i spend time (and basically the same amount of money) to build the PCB and flash some software instead of buying a really cheap but reliable pcb, already populated and with the right software flashed. I can actually have more fun hacking a standard naked module into a fully functional device.
The main upgrade is to replace the 9V battery with a 18650 Li-Ion cell with its charge/discharge protection module. I want my tester to be rechargable and to be potentially powered by either usb port or whatever power supply that can provide 5V. There's more! Evenf if you compare the 18650 with a rechargable 9V battery the mod will be more flexibile because you don't have to open the case to charge it and, even more useful, you don't have to wait if the battery is depleted. Just plug in an usb cable or a 5V power supply and use the tester immediately. (a depleted 9V rechargable battery have to be put it under charge for a while)
Last mod is to have an additional testing port to allow some phisically big components to be tested. To do that i'll add a 3 pin dupont female connector on the side. You can attach everything you want to these pins, i simply use another dupont connector (male) with three test clips/probes.
Step 1: Components and Tools
I suggest to purchase the module on Bangood since i can't guarantee that the Amazon seller will deliver the very same module, the picture and the description are ok but who knows...
Since you would follow this instructable only if you want to reclaim electronic components i won't spend time to tell you that you'll need a soldering iron, wires, etc...
You should be able to reclaim 18650 cell from whatever laptop battery you have at hand but, in case you don't have any or don't want to bother with li ion reclaiming, you can purchase one cell from Bangood or Amazon. You "shouldn't" purchase these too-cheap-to-be-good cells for other projects because they won't match their specs for sure, but on the other hand this project's power requirement is so tiny that it doesn't really matter.
Hint: the three pin dupont could be a spare servo (RC servo) cable.
Step 2: Print the Case
Now follow this link and download the files. The printing instructions are on the Thingiverse page but it actually is a really easy-to-print case, you shouldn't need any instructions.
Pla, abs, whatever filament will do the trick.
Step 3: Electrical Wiring
As you can see the eletrical drawing is quite simple, you have to perform these few connections:
- connect the TP4056 output pads with the step-up input pads with a couple of wires
- connect the TP4056 input pads with the 2 pin recharge connector
- connect the TP4056 battery pads to the 18650 cell
- remove the 9V original connector
- connect the step-up output to the module input
- connect the 3 pin dupont connector with the first 3 pin of the blue spring socket.
By "connect" i obviously mean "solder" a cable. Be really careful with the soldering on the li-ion cell, it's dangerous! There are plenty of suggestions and tutorial about this step online, just search "18650 soldering". Be sure to have understood how to do that in a safe way (basically: be as quick as possibile because the heat of the soldering iron will damage the cell).
The battery cables have their paths/holes in the bottom part of the case, please use them.
The step-up module have to be set to output 9V as soon as possible and you can do that turning its trimmer with a simple screwdriver. You have to do that mandatory before the 5th step and you can easily do that once you've performed the 3rd step, just don't forget it!
Once soldered everything you should check with a multimeter the effectiveness of every connection and check id every pad isn't shorted with another one.
If everything is ok press the tester only button to see if it powers up and it works properly.
Step 4: Finalize the Case
Now all the components (also the 18650 cell!) can be attached to the case with few drops of hot glue. I suggest to use few drops of glue also on the soldered connections, to prevent mechanical stress. You can/should also use some glue to attach the 3 pin dupont connector on the frame. I've added a zip tie on the 2 pin recharge connector, as usual to avoid every chance of mechanical stress when i plug and uplug it.
You can/should add a small sponge cube or whatever soft material to be sure the 18650 will remain in place in case the hot glue will fail over time (it's the only heavy components, therefore the most exposed to mechanical stress).
Once the glue is cold you can carefully close the case with 4x M3x25 screw. The nuts have their slot in the bottom of the case but they aren't mandatory (the screws can tap the holes).
It's done, now you have your li-ion powered component tester, happy days!
Step 5: Usage
I've learned from the comments that i should add more info about how to use this tester. The testing operation is actually quite easy, you only have to connect the component that you want to identify and then press the only button. If the tester can identify the component it will show the component's device class and its main specs, otherwise it will say that it can't identify the component or that the component is damaged. This could happen, for instance, if you connect a 7805 linear regulator, it's not damaged but it can't be identified. In other words you can't determine if an unkown TO-220 item is a faulty mosfet or a functioning linear regulator.
You can connect the item to be tested in three way:
- by the cyan spring connector (ZIF socket): put the item's legs in the holes and push the small lever down
- by the smd pads: place the item on the exposed pads in the central funnel
- by the external probes connector (if you added the 3 pin dupont connector)
The external probes connector can work with whichever probes you want, as long as they can be wired to a dupont male connector. I've used three small hook probes and another servo cable but you could use alligators clip and any three wire cable., it doesn't matter
ps: the zif socket is a 7x2 socket and as i mention before the three "logical" input have multiple phisical connections. The pin numbers are:
123 - 1111
222 - 3333
That's all, happy component tester, folks!
ps: if you find this -ible interesting or it helped you please consider a little paypal donation, it will be appreciated.