- Electronic Parts
- Heat Sink
- USB --> TTL adapter board (optional)
- USB Male – Female extension cable for above
- ICSP programmer w/6-pin adapter
- 4x TO-220 Insulated mounting hardware
- Thermal grease
- Mounting hardware
- 4x #6 x 3/4" pan-head machine screw
- 4x #6 x 1/4” insulating nylon standoffs
Total cost for all of the above should be will under $100, and much lower depending on if you implement Bluetooth or not.
PCBI often have a supply of PCBs available, see the right to check that status. Alternatively you can use the resource tabs above and download the latest GBR files to be used with the PCB fabricator of your choice. (or the CAD files, make mods as you wish and go from there!) When making up the PCBs I use standard thickness and 1oz copper, you can consider upgrading to 2oz copper if you expect to drive high field current (or perhaps two alternators in parallel). Alternatively, there are open places in the solder mask which can be used to 'reinforce' the field drive traces - just solder on some short wires in those spots to help carry any field current.
ELECTRONIC PARTSFor convenience I use Mouser.com for sourcing my parts - to be honest, mostly because they seem to not mind too much (or at least do not complain too much) selling small quantities of parts, and their web page is a bit better then other supply houses when it comes to locating and comparing components. Under the resource tab 'Parts List' above you will find a .xls sheet with the BOM, I also have places a 'scrubbed BOM' at Mouser.com (as of December 2014) that can be access using this link:
Do note this mouser BOM is for v0.1.4 of the PCB and includes the Bluetooth module. If you wish to not use the Bluetooth, make sure to check the schematic for part changes - specifically:
- Do not order the RN-41 Bluetooth module
- Replace D18 with a 10K resistor
- Change C19 to a 0.1uF capacitor
And of course there are other sources than Mouser.com - nothing magic about anything in the board - do take note the 8Mhz crystal picked uses 33pf loading caps (it was what was available when I 1st selected parts for this project), if you select a different crystal - make sure to match up the loading caps C13 / C14 to the specs of the crystal.
HEAT SINKPerhaps the hardest part to source. The Arduino Alternator Regulator really does not produce that much heat, but a small amount of thermal capability is needed - mostly on Q1 and U1. When designing this I selected a heat sink largely for its physical protection. The part I designed to is a: Hongfa HF92B-120 (http://octopart.com/hf92b-120-hongfa-19677676). It is designed to support a couple of SSRs (Solid State Relays) and was selected due to its large flat space in the middle. In fact, the PCB is designed to fit this space with an overall size of 105mm x 55mm. The problem is this part is a PITA to source - and my experience with the one supplier out of Australia is a little less then positive - esp with regards to shipping costs. So, here is some additional data for you and some ideas for alternatives:
Heat Displacement of the regulator is documented here:
In most cases, it will be rather modest. Some ideas for alternatives heat sinks might include:
- Modify more commonly available heat-sink, removing a fin to get a bit more width if needed.
- For example: Orman - Y92B-A150N
- Wakefield 423K
- Any Fine Type heat-sink.. Look on Ebay, local supply house, scrap bin
- Utilize some extruded 'L' shape aluminum stock?
- A die-cast metal box?
COMPUTER ADAPTERSThere is one adapter you will need, and one more you likely will want. Because a custom boot-loader is needed (a 3.3v opti-boot), you will need to gain access to an ICSP tool. And ideally a 3.3v capable one. I use a widely available open-source tool based on the USBasp. It should be available off of EBay for under $5 or so, make sure you have some way to get to the 6-pin ICSP connector used by the Arduino Alternator Regulator (Either via an adapter board, or just some jumper wires as I use). There are a few more details involved which I have documented here:
Make sure to note the need to have a good solid 3.3v power source while burning the bootloader - (a USBasp by its self will not be sufficient) Either hook up the regulator's Enable pin to an external power supply, or you can get sufficient current if you also use the Serial Service Port adapter described next.
The other board which you might find helpful is a USB <--> Serial adapter board. Once the Bootloader is flashed in you can use this board via the Service Port to load sketches. It also provided a way to gain access to Serial ASCII string status outputs as well as a way to send ASCII commands to the regulate - if you do not wish to use the Bluetooth module (or wish to 'override' it temperately). I have designed the regulator to directly connect with certain 6-pin adapters - and I selected those adapters as they are able to supply 3.3v as well as 5v without any switches or jumpers needed. In this way, all my projects use the same adapter board and you do not need to worry about setting switches. Take note this is NOT the same pin-outs as used on the small Arduino boards...
I purchase mine from Ebay for around $2 each using the search string: “CP2102 USB 2.0 to TTL UART Module 6Pin Serial Converter STC Replace FT232” . If you take care to get one with the pinout of this spec you can directly plug it into the Service Port:
|Example of 6-pin adapter with correct pin-outs|
(Click on picture for larger view)
Of course other serial adapters can be used (you can even pull the ATmega328 out of an Arduino UNO and use that) - you will just need to match up the pins. You do need to make sure you can get access to the DTR signal, as that is used by the Arduino IDE to reset the uC and allow sketches to be loaded. Do not confuse this with adapters which have a pin labeled 'reset' or 'rst' - often those pins are used to reset the USB adapter, and will not work with the Arduino IDE without modification.
MOUNTING HARDWAREFinally you will need some mounting hardware. TO-220 insulating hardware and screw sets. Mouser has them (e.g.: 534-4724 for a couple buck each), or you can order in bulk - myself I again look to Ebay! Make sure to get some thermal grease as well.
To mount the regulator to the case / heatsink of your choosing you can use nylon standoff spacers that match the off-set you used when soldering in Q1, Q2 and Q4 (the TO-220 parts mounted on the bottom of the PCB). Used 1/4" - because in the USA 1/4" nylon spacers are easily found. But of course you can use what you wish. The 4 mounting holes in the corners of the PCB are 0.120" in diameter (approx 3mm). I found they are just right to allow taping for a #6 machine screw - a 3.5mm machine screw should work just as well. I then just ran a machine screw up through the underside of the heatsink, put on a spacer and gently screwed it into the PCB - letting the PCB act as the 'nut'. If you want you can add threaded nylon spacers to the top of the PCB, screwing onto the protruding stud and perhaps that can hold some type of overall cover. To see a bit more details on how I mounted my regulator, click here: