Ralf Ackermann sent in this suggestion for soldering an alternate connector straight to an SD card for a cheaper way to use SD/MMC cards in an embedded project. Pictured is his ATMega based MIDI recorder/player that uses this design.
This reminded me of another hack by Rob Wentworth. He noticed that the pin spacing on old floppy disk connectors are roughly the same as SD pins.
With just a couple of shims to hold the card in the correct position, you can use this connector almost without modification–to the connector, or the card.
I must admit, I’m a bit out of the loop on this one. Are SD connectors that expensive or hard to come by? If so, what’s the best way to use them in your projects without using the legit connector?
Cheaper MMC/SD Adapter
SD/MMC card fits in floppy edge-connector
10 thoughts on “Alternative MMC/SD connector hacks”
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Sparkfun sells an “SD/MMC Socket for Secure Digital Disk or Multi Media Cards” (sku: PRT-00136) for $3.95, which isn’t too bad. It does appear to have pretty small connections, though.
Sparkfun does sell a “Breakout Board for SD-MMC Cards “(sku: BOB-00204), with the SD/MMC socket, for $17.95. Fourteen dollars is a bit pricey for a 1.3×1.5” PCB that has been, etched, silk-screened, and the SD/MMC socket soldered on board. Such is the price of convenience.
For those that are sufficiently skilled, they could make the carrier board and solder the SD/MMC socket to it. Otherwise, either of the solutions covered by Jason are cheap and do work. The solution presented by Ralf Ackerman is very compact, though a bit permanent, as far as the MMC device is concerned. Also, if one went to the effort to hack the SD to micro SD adapter for this solution, then one may as well make a breakout board carrier for an SD/MMC socket. Then, and SD/MMC device could be plugged in.
I like this cheapo version pretty well but it is a dead end if you want to swap out the memory chip.
If you solder in a mini SD to SD adapter instead, you can either slip in a miniSD card or a microSD in a microSD to miniSD adapter.
The adapters frequently come free with microSD cards.
I had the same idea, I wrote about it here
http://frank.circleofcurrent.com/sdcard_tinyfatfs.php
I’ve made a MP3 player and I’m still writing about it
Why not use SD connector from an old card reader? You can buy a bunch of these for a price of one new SD connector. Or better, ask someone ho sells them to send you some with broken electronics.
Me and my friend built a few SD readers from scratch using a Floppy drive’s metal slider, some aluminum strips, alot of glue and a few wires… Too bad I don’t know where they are anymore.