Coolgate Variable Voltage mod

[CapeCAD]

We were snowed in tody, electricity and internet were out, so I began planning to modify my old Colgate toothbrush into a variable voltage mod using the Murata Power Solutions Okami Buck Converter.

I've assembled and tested everything, but I'm adding a connector inline with the addy, so that has not been inserted yet.

This mod is completely sealed and uses the switch already on the toothbrush to turn the enable of the converter on and off.

This toothbrush already accepted AA batteries, so modifications were minimal. There is even room in there to add other options.

View attachment Coolgate-2.pdf
View attachment Coolgate-3.pdf
View attachment Coolgate-4.pdf
View attachment Coolgate-1.pdf
View attachment CoolgateSch.pdf

 

[CapeCAD]

Some additional pictures

View attachment Coolgate-6.pdf
View attachment Coolgate-7.pdf
View attachment Coolgate-8.pdf
View attachment Coolgate-5.pdf
View attachment Coolgate-9.pdf

 

[rannox]

Hahaha, I gotta admit, that is pretty awesome, does it still function as a tooth bruth?

 

[SurvivorMcGyver]

So with this chip, do you find the caps help to stabilize in a bit? I noticed you used a 240 ohm in series with the pot are you still able to get the full 6V out with that? My calcs show it would be just above 5.5V -- I've tried to come as close to 218 as possible using parralelled 499 and 390 yielding 218.9ohms to try to get the mostest from the bestest {chuckling} has that been overkill?

Sweet how you sinked the Ground pin and are using the NO switch

This is a nice trick folks on open drain collector pins that will accept Max Vin - especially for those thinking you need a NC switch to control this unit.

So does the atties oscillate when you hit the vape switch? -- Fantastic added effect it it does

 

[Java_Az]

Nice work, I bet those 0805's are fun to solder. You use a iron to Solder those ? I messed up on my last order and got some 0201's they look like a spec of dirt threw the magnified glass. I believe a microscope would be needed for me to try solder them.

 

[CapeCAD]

So with this chip, do you find the caps help to stabilize in a bit? I noticed you used a 240 ohm in series with the pot are you still able to get the full 6V out with that? My calcs show it would be just above 5.5V -- I've tried to come as close to 218 as possible using parralelled 499 and 390 yielding 218.9ohms to try to get the mostest from the bestest {chuckling} has that been overkill?

That's what I get for posting late at night, I used a 220 Ohm resistor on this mod and I'm getting 5.9V max output. I've made other mods with the 240 Ohm because I wanted to limit the output since I've burned through several atties by having it set too high.

I've been considering using a higher value (270 Ohm) to limit the output to under 5V.

I used the caps because I have about an inch of wire between the converter and connector. I have not seen a need for external caps with this converter when connections are shorter, but it never hurts to add them.

So does the atties oscillate when you hit the vape switch? -- Fantastic added effect it it does

Unfortunately no oscillation, that would make it sound more like the original electric toothbrush if it did.

Nice work, I bet those 0805's are fun to solder. You use a iron to Solder those ? I messed up on my last order and got some 0201's they look like a spec of dirt threw the magnified glass. I believe a microscope would be needed for me to try solder them.

I use a Weller WESD51 soldering iron. I've been working with 0603's and an occasional 0402 on my SEPIC converter, so 0805's seem much larger now (I use a desk mounted 3X magnifier).

I've found this works best for me:

1. Small dot of flux on the PCB where one side of the component goes.
2. Add small amount of solder to tip of iron.
3. Hold component in place with tweezers.
4. Touch the flux side with the iron.
5. Now that the component is tacked in place, it's easy to solder the other side and go back to touch up the first side if needed.

 

[SurvivorMcGyver]

Have you tried any of the Component epoxies? I need a dang third hand when using tweezers.... I've been reluctant to go the epoxy route due to the cost and that fact that most cartriges are designed for machine application. I'm thinking this may help (me) as I often get the standard "pull" when I solder one side (which raises the other when it cools) - this on 0805's. Any hints?

Chuckling - I even fabricated a sanded down clothspin to help hold the suckers on the first tack - but it still gets in the way and often won't fit when I need it to.

You'll have to start a tread on your SMD Soldering Oven methods some day I've got several grarage sale toaster ovens awaiting modification.

 

[MrByte]

CapeCAD, I noticed that your schematic has the trim pin labled as pin 4, but the data sheet is saying pin 4 is Vout.

In mocking up my chip, I can't seem to get it to regulate at all using the datasheet's info, all I ever get is Vout around .5V less than Vin. Unless I remove ground, then I get about 4.4Vout.

Just wondering if I blew my regulator. I stick a TI PTR08060 in and it doesn't put out until I put in a resistor as per specs...

 

[Java_Az]

CapeCAD, I noticed that your schematic has the trim pin labled as pin 4, but the data sheet is saying pin 4 is Vout.

In mocking up my chip, I can't seem to get it to regulate at all using the datasheet's info, all I ever get is Vout around .5V less than Vin. Unless I remove ground, then I get about 4.4Vout.

Just wondering if I blew my regulator. I stick a TI PTR08060 in and it doesn't put out until I put in a resistor as per specs...

The schematic is for a OKR-T/3-W12 chip not a PTR08060w . There is a difference in the inhibit pins on the two models. What are you removing the ground from?

 

[CapeCAD]

The pin numbers (4 & 5) are reversed, the functions are connected correctly.
This OKR is a positive logic device (Inhibit to Gnd = off), resistor to ground keeps this device off until Vin is applied.

 

[MrByte]

The schematic is for a OKR-T/3-W12 chip not a PTR08060w . There is a difference in the inhibit pins on the two models. What are you removing the ground from?

I know they are different, but they both work with this circuit, just replace the 100k for a 10k resistor. Actually, the 10K seems to do fine with the OKR regulator as well.

I suspect I was having connection issues with the breadboard or something as they now are working. I have 1 TI chip and 2 OKR's, and I'm building 2 units based on the OKR for myself and a buddy to test. I may try the TI chip for fun and games, but the TI's price is a bit high for me. I had 2 TI's as samples, but broke the pins off one.

I was just leaving pin 3 open, with no connection to the ground from the battery.

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Ok, so today wasn't my day after all. Out of 4, 2 TI's and 2 OKR's, I have 1 OKR working...

Too long with the heat from the iron? I didn't think I was there that long, really.

 

[CapeCAD]

I suspect I was having connection issues with the breadboard or something as they now are working.

Glad to hear my typo didn't cause you a problem.

Sorry to hear you are having difficulty soldering both converters. I've been applying a little flux to the pins, adding solder to the tip of my iron, and just touching the connection for a split second. I haven't lost a converter yet.

Good luck