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The sub £30 mintypi?!?

Posted: Sun Aug 27, 2017 3:52 pm
by Holydohnut
I'm expecting to get laughed at here. But I was just adding up the cost of my 2nd mintypi, and I think I may be on track to building it for less than £30! Now before you have me strung up for telling porky pies, I will offer the following caveats.

1. I own a 3D printer. So thanks to wermy's generosity, I can amend and print the plastics myself.
2. By blind luck, I won an eBay auction for 5 broken ds lites for £8. Meaning the buttons and screws for one minty, equate to just £1.60. (The speaker is also a bulk buy, 99p for 2 = 50p each)
3. After building a minty based on Helders PCB already, I set myself the challenge of building one from scratch. So this one is a 2.2" screen and a custom (bodged) pcb.

So where are the numbers I hear you cry! Here goes...

Altoids tin - £1.00 Morrisons
Speaker - eBay - 50p (99p\2)
Sound card - ebay - £2.77
Battery - eBay - £6.95
Charging board - eBay - £1.69 (Do NOT use this unless you are comfortable desoldering and resoldering the surface mount resistor)
Screen - eBay - £5.25
Dslite to chop up and harvest buttons, pcb, and screws from - eBay - £1.60
Pi zero (not w) - Pimoroni - £4.32 (10% off code) + £2.50 shipping (the only item I paid shipping on!)
Switch - eBay - 99p

Total cost £27.57

So £2.43 towards wiring and 4 tack switches. (these were bought in bulk many years ago!)

Am I missing anything? Genuine question Coz I still can't quite believe it myself! It could be even cheaper too! If I had more patience, I could probably get the most expensive item, (The battery) cheaper from China. The one I listed is UK based. And the charging boards could be bought in bulk for a little over 50p a piece! (cost above is just for one.)

Who says this is an expensive hobby? :-D

Re: The sub £30 mintypi?!?

Posted: Sun Aug 27, 2017 4:03 pm
by Holydohnut
Ah, dang it. Just remembered the micro Sd card! Nuts! Still pretty cheap though!

Re: The sub £30 mintypi?!?

Posted: Sun Aug 27, 2017 4:32 pm
by Helder
Do it! I want to see how it comes out it would inspire people to do more DIY on these things.

Re: The sub £30 mintypi?!?

Posted: Sun Aug 27, 2017 4:36 pm
by moosepr
Why do you need to be able to surface mount for the battery board?

The crazy thing about these projects is that the pi is normally one of the cheapest parts!

Re: The sub £30 mintypi?!?

Posted: Sun Aug 27, 2017 4:49 pm
by Holydohnut
Sorry. That was badly worded. You have to remove the surface mount resistor, but I guess you don't have to replace it with one. A through whole one would be fine. It's a TP4056 with the battery protection.

Re: The sub £30 mintypi?!?

Posted: Sun Aug 27, 2017 5:16 pm
by HoolyHoo
Sub 30 pounds, pffft! I made this one for only a couple bucks, lol.
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Re: The sub £30 mintypi?!?

Posted: Sun Aug 27, 2017 6:16 pm
by moosepr
I have used the tp4056 boards in all my projects, and never had to alter them

Re: The sub £30 mintypi?!?

Posted: Sun Aug 27, 2017 6:17 pm
by 144TECH
Oh great man, those carrot buttons :mrgreen: but still you can't play butter cheese and eggs lol :D

Re: The sub £30 mintypi?!?

Posted: Mon Aug 28, 2017 1:29 am
by Holydohnut
The instructions on the eBay site say to change out the resistor if you're using a sub 2000mah battery. They provide a general guide on which one to use and say the charge current should be 37% of the battery. So to use a 1200mah a 2k resistor would knock the charge down to around 500mah.

But if you reckon you've used one for batteries of this size with no issue moosepr, that's good enough for me! Your tiny screen guides set me on this path and what's more, I've recently bought a 1.4" screen for my first self build, after seeing you use one in your pocket pi! You're kinda my hero at the moment!

Re: The sub £30 mintypi?!?

Posted: Mon Aug 28, 2017 3:11 am
by moosepr
Yeah, I have even been charging a 240mah battery in my tinyPi with one! It might be worth checking data sheets and such, but I think the general rule is that you can give up to 1c when charging. So a 3000mah battery can safely take 3 amps on a charge.

So the 1 amp from your board will be fine for your 1200mah battery